From c8cfdadc8850f0415e7ba868b494ff7fd2d23830 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Thu, 28 May 2020 15:53:00 -0400
Subject: [PATCH 01/32] Add relevant exceptions for enabling/disabling

---
 .../DependentExtensionsException.php          | 35 +++++++++++++++++++
 .../MissingDependenciesException.php          | 35 +++++++++++++++++++
 2 files changed, 70 insertions(+)
 create mode 100644 src/Extension/Exception/DependentExtensionsException.php
 create mode 100644 src/Extension/Exception/MissingDependenciesException.php

diff --git a/src/Extension/Exception/DependentExtensionsException.php b/src/Extension/Exception/DependentExtensionsException.php
new file mode 100644
index 0000000000..a906add1c3
--- /dev/null
+++ b/src/Extension/Exception/DependentExtensionsException.php
@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Exception;
+use Flarum\Extension\Extension;
+use Flarum\Foundation\KnownError;
+
+class DependentExtensionsException extends Exception implements KnownError
+{
+    public $extension;
+    public $dependent_extensions;
+
+    /**
+     * @param $extension: The extension we are attempting to activate.
+     * @param $dependent_extensions: Extension IDs of the Flarum extensions that depend on this extension
+     */
+    public function __construct(Extension $extension, array $dependent_extensions = [])
+    {
+        $this->extension = $extension;
+        $this->$dependent_extensions = $dependent_extensions;
+    }
+
+    public function getType(): string
+    {
+        return 'dependent_extensions';
+    }
+}
diff --git a/src/Extension/Exception/MissingDependenciesException.php b/src/Extension/Exception/MissingDependenciesException.php
new file mode 100644
index 0000000000..f3216df8a1
--- /dev/null
+++ b/src/Extension/Exception/MissingDependenciesException.php
@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Exception;
+use Flarum\Extension\Extension;
+use Flarum\Foundation\KnownError;
+
+class MissingDependenciesException extends Exception implements KnownError
+{
+    public $extension;
+    public $flarum_dependencies;
+
+    /**
+     * @param $extension: The extension we are attempting to activate.
+     * @param $flarum_dependencies: Extension IDs of the missing flarum extension dependencies for this extension
+     */
+    public function __construct(Extension $extension, array $flarum_dependencies = [])
+    {
+        $this->extension = $extension;
+        $this->$flarum_dependencies = $flarum_dependencies;
+    }
+
+    public function getType(): string
+    {
+        return 'missing_dependencies';
+    }
+}

From e50f22ba1750da0da86fa6aa5a0ccc26a245e450 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Thu, 28 May 2020 15:53:29 -0400
Subject: [PATCH 02/32] Add helper method for getting flarum extension
 dependencies

---
 src/Extension/Extension.php | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index 3707bfae08..648aef78df 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -221,6 +221,13 @@ public function getIcon()
         return $icon;
     }
 
+    /**
+     * Get the list of flarum extensions that this extension depends on
+     */
+    public function getFlarumExtensionDependencies() {
+        return $this->composerJsonAttribute('extra.flarum-extension.dependencies.extensions');
+    }
+
     public function enable(Container $container)
     {
         foreach ($this->getLifecycleExtenders() as $extender) {
@@ -363,12 +370,13 @@ public function migrate(Migrator $migrator, $direction = 'up')
     public function toArray()
     {
         return (array) array_merge([
-            'id'            => $this->getId(),
-            'version'       => $this->getVersion(),
-            'path'          => $this->path,
-            'icon'          => $this->getIcon(),
-            'hasAssets'     => $this->hasAssets(),
-            'hasMigrations' => $this->hasMigrations(),
+            'id'                    => $this->getId(),
+            'version'               => $this->getVersion(),
+            'path'                  => $this->path,
+            'icon'                  => $this->getIcon(),
+            'hasAssets'             => $this->hasAssets(),
+            'hasMigrations'         => $this->hasMigrations(),
+            'extensionDependencies' => $this->getFlarumExtensionDependencies(),
         ], $this->composerJson);
     }
 }

From 7937f82f3146ae442a010d30d534133f44c38cfa Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Thu, 28 May 2020 15:54:22 -0400
Subject: [PATCH 03/32] Add extension dependency resolver (Kahn's algorithm),
 plus unit tests

---
 src/Extension/ExtensionManager.php            | 112 ++++++++++++++++++
 .../ExtensionDependencyResolutionTest.php     | 107 +++++++++++++++++
 2 files changed, 219 insertions(+)
 create mode 100644 tests/unit/Foundation/ExtensionDependencyResolutionTest.php

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 40136e3484..db0c945d0a 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -15,6 +15,7 @@
 use Flarum\Extension\Event\Enabled;
 use Flarum\Extension\Event\Enabling;
 use Flarum\Extension\Event\Uninstalled;
+use Flarum\Extension\Exception\DependentExtensionsException;
 use Flarum\Foundation\Paths;
 use Flarum\Settings\SettingsRepositoryInterface;
 use Illuminate\Contracts\Container\Container;
@@ -133,6 +134,18 @@ public function enable($name)
 
         $extension = $this->getExtension($name);
 
+        $missingDependencies = [];
+        $enabled = $this->getEnabled();
+        foreach ($extension->getFlarumExtensionDependencies() as $dependency) {
+            if (!in_array($dependency, $enabled)) {
+                $missingDependencies[] = $dependency;
+            }
+        }
+
+        if (!empty($missingDependencies)) {
+            throw new Exception\MissingDependenciesException($extension, $missingDependencies);
+        }
+
         $this->dispatcher->dispatch(new Enabling($extension));
 
         $enabled = $this->getEnabled();
@@ -165,6 +178,22 @@ public function disable($name)
 
         $extension = $this->getExtension($name);
 
+        $dependentExtensions = [];
+
+        foreach ($this->getEnabledExtensions() as $possibleDependent) {
+            foreach ($possibleDependent->getFlarumExtensionDependencies() as $dependency) {
+                if ($dependency === $extension->getId()) {
+                    $dependentExtensions[] = $dependency;
+                    // No need to cycle through the rest of this extension's dependencies.
+                    break;
+                }
+            }
+        }
+
+        if (!empty($dependentExtensions)) {
+            throw new DependentExtensionsException($extension, $dependentExtensions);
+        }
+
         $this->dispatcher->dispatch(new Disabling($extension));
 
         unset($enabled[$k]);
@@ -335,4 +364,87 @@ public function isEnabled($extension)
 
         return isset($enabled[$extension]);
     }
+
+    /**
+     * Sort a list of extensions so that they are properly resolved in respect to order.
+     * Effectively just topological sorting.
+     *
+     * @param $extensionList: an array of \Flarum\Extension\Extension objects
+     *
+     * @return array with 2 keys: 'extensions' points to an ordered array of \Flarum\Extension\Extension
+     *                            'missingDependencies' points to an associative array of extensions that could not be resolved due
+     *                                to missing dependencies, in the format extension id => array of missing dependency IDs.
+     *                            'circularDependencies' points to an array of extensions ids of extensions
+     *                                that cannot be processed due to circular dependencies
+     */
+    public static function resolveExtensionOrder($extensionList)
+    {
+        $extensionIdMapping = []; // Used for caching so we don't rerun ->getExtensions every time.
+
+        // This is an implementation of Kahn's Algorithm (https://dl.acm.org/doi/10.1145/368996.369025)
+        $extensionGraph = [];
+        $output = [];
+        $missingDependencies = []; // Extensions are invalid if they are missing dependencies, or have circular dependencies.
+        $circularDependencies = [];
+        $pendingQueue = [];
+        $inDegreeCount = []; // How many extensions are dependent on a given extension?
+
+
+        foreach ($extensionList as $extension) {
+            $extensionIdMapping[$extension->getId()] = $extension;
+            $extensionGraph[$extension->getId()] = $extension->getFlarumExtensionDependencies();
+
+            foreach ($extension->getFlarumExtensionDependencies() as $dependency) {
+                $inDegreeCount[$dependency] = array_key_exists($dependency, $inDegreeCount) ? $inDegreeCount[$dependency] + 1 : 1;
+            }
+        }
+
+        foreach ($extensionList as $extension) {
+            if (!array_key_exists($extension->getId(), $inDegreeCount)) {
+                $inDegreeCount[$extension->getId()] = 0;
+                $pendingQueue[] = $extension->getId();
+            }
+        }
+
+        while (! empty($pendingQueue)) {
+            $activeNode = array_shift($pendingQueue);
+            $output[] = $activeNode;
+
+            foreach ($extensionGraph[$activeNode] as $dependency) {
+                $inDegreeCount[$dependency] -= 1;
+
+                if ($inDegreeCount[$dependency] === 0) {
+                    if (!array_key_exists($dependency, $extensionGraph)) {
+                        // Missing Dependency
+                        $missingDependencies[$activeNode] = array_merge(
+                            Arr::get($missingDependencies, $activeNode, []),
+                            [$dependency]
+                        );
+                    } else {
+                        $pendingQueue[] = $dependency;
+                    }
+                }
+            }
+        }
+
+        $validOutput = array_filter($output, function ($extension) use ($missingDependencies) {
+            return !array_key_exists($extension, $missingDependencies);
+        });
+
+        $validExtensions = array_reverse(array_map(function($extensionId) use ($extensionIdMapping) {
+            return $extensionIdMapping[$extensionId];
+        }, $validOutput)); // Reversed as required by Kahn's algorithm.
+
+        foreach ($inDegreeCount as $id => $count) {
+            if ($count != 0) {
+                $circularDependencies[] = $id;
+            }
+        }
+
+        return [
+            'valid' => $validExtensions,
+            'missingDependencies' => $missingDependencies,
+            'circularDependencies' => $circularDependencies
+        ];
+    }
 }
diff --git a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
new file mode 100644
index 0000000000..6cbae7fe39
--- /dev/null
+++ b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
@@ -0,0 +1,107 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Tests\unit\Foundation;
+
+use Flarum\Extension\ExtensionManager;
+use Flarum\Tests\unit\TestCase;
+
+class ExtensionDependencyResolutionTest extends TestCase
+{
+    public function setUp()
+    {
+        parent::setUp();
+
+        $this->tags = new FakeExtension('flarum-tags', []);
+        $this->categories = new FakeExtension('flarum-categories', ['flarum-tags', 'flarum-tag-backgrounds']);
+        $this->tagBackgrounds = new FakeExtension('flarum-tag-backgrounds', ['flarum-tags']);
+        $this->something = new FakeExtension('flarum-something', ['flarum-categories', 'flarum-help']);
+        $this->help = new FakeExtension('flarum-help', []);
+        $this->missing = new FakeExtension('flarum-missing', ['this-does-not-exist', 'flarum-tags', 'also-not-exists']);
+        $this->circular1 = new FakeExtension('circular1', ['circular2']);
+        $this->circular2 = new FakeExtension('circular2', ['circular1']);
+    }
+
+
+    /** @test */
+    public function works_with_empty_set()
+    {
+        $expected = [
+            'valid' => [],
+            'missingDependencies' => [],
+            'circularDependencies' => [],
+        ];
+
+        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder([]));
+    }
+
+    /** @test */
+    public function works_with_proper_data()
+    {
+        $exts = [$this->tags, $this->categories, $this->tagBackgrounds, $this->something, $this->help];
+
+        $expected = [
+            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
+            'missingDependencies' => [],
+            'circularDependencies' => [],
+        ];
+
+        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
+    }
+
+    /** @test */
+    public function works_with_missing_dependencies()
+    {
+        $exts = [$this->tags, $this->categories, $this->tagBackgrounds, $this->something, $this->help, $this->missing];
+
+        $expected = [
+            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
+            'missingDependencies' => ['flarum-missing' => ['this-does-not-exist', 'also-not-exists']],
+            'circularDependencies' => [],
+        ];
+
+        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
+    }
+
+    /** @test */
+    public function works_with_circular_dependencies()
+    {
+        $exts = [$this->tags, $this->categories, $this->tagBackgrounds, $this->something, $this->help, $this->circular1, $this->circular2];
+
+        $expected = [
+            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
+            'missingDependencies' => [],
+            'circularDependencies' => ['circular2', 'circular1'],
+        ];
+
+        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
+    }
+}
+
+class FakeExtension
+{
+    protected $id;
+    protected $dependencies;
+
+    public function __construct($id, $dependencies)
+    {
+        $this->id = $id;
+        $this->dependencies = $dependencies;
+    }
+
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    public function getFlarumExtensionDependencies()
+    {
+        return $this->dependencies;
+    }
+}

From acc4f65ba8a9886647253189eddfb2a9d5bbcaa2 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Thu, 28 May 2020 16:01:36 -0400
Subject: [PATCH 04/32] Enable extensions in proper order

---
 src/Extension/ExtensionManager.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index db0c945d0a..22df21866c 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -325,7 +325,9 @@ public function getEnabledExtensions()
      */
     public function extend(Container $app)
     {
-        foreach ($this->getEnabledExtensions() as $extension) {
+        $enabled = static::resolveExtensionOrder($this->getEnabledExtensions());
+
+        foreach ($enabled['valid'] as $extension) {
             $extension->extend($app);
         }
     }

From ec3cd0cf3a01ae83b6bbfc62c7877d35c329a642 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Thu, 28 May 2020 16:29:39 -0400
Subject: [PATCH 05/32] Fix no default when getting extension dependencies

---
 src/Extension/Extension.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index 648aef78df..ce84a187b8 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -225,7 +225,7 @@ public function getIcon()
      * Get the list of flarum extensions that this extension depends on
      */
     public function getFlarumExtensionDependencies() {
-        return $this->composerJsonAttribute('extra.flarum-extension.dependencies.extensions');
+        return Arr::get($this->composerJson, 'extra.flarum-extension.dependencies.extensions', []);
     }
 
     public function enable(Container $container)

From 0722382978c1624dca71564d42920da04b005b87 Mon Sep 17 00:00:00 2001
From: luceos <daniel+github@klabbers.email>
Date: Thu, 28 May 2020 20:30:15 +0000
Subject: [PATCH 06/32] Apply fixes from StyleCI

[ci skip] [skip ci]
---
 src/Extension/Extension.php                       |  5 +++--
 src/Extension/ExtensionManager.php                | 15 +++++++--------
 .../ExtensionDependencyResolutionTest.php         |  1 -
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index ce84a187b8..881d6a2472 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -222,9 +222,10 @@ public function getIcon()
     }
 
     /**
-     * Get the list of flarum extensions that this extension depends on
+     * Get the list of flarum extensions that this extension depends on.
      */
-    public function getFlarumExtensionDependencies() {
+    public function getFlarumExtensionDependencies()
+    {
         return Arr::get($this->composerJson, 'extra.flarum-extension.dependencies.extensions', []);
     }
 
diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 22df21866c..e6fdd96639 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -137,12 +137,12 @@ public function enable($name)
         $missingDependencies = [];
         $enabled = $this->getEnabled();
         foreach ($extension->getFlarumExtensionDependencies() as $dependency) {
-            if (!in_array($dependency, $enabled)) {
+            if (! in_array($dependency, $enabled)) {
                 $missingDependencies[] = $dependency;
             }
         }
 
-        if (!empty($missingDependencies)) {
+        if (! empty($missingDependencies)) {
             throw new Exception\MissingDependenciesException($extension, $missingDependencies);
         }
 
@@ -190,7 +190,7 @@ public function disable($name)
             }
         }
 
-        if (!empty($dependentExtensions)) {
+        if (! empty($dependentExtensions)) {
             throw new DependentExtensionsException($extension, $dependentExtensions);
         }
 
@@ -391,7 +391,6 @@ public static function resolveExtensionOrder($extensionList)
         $pendingQueue = [];
         $inDegreeCount = []; // How many extensions are dependent on a given extension?
 
-
         foreach ($extensionList as $extension) {
             $extensionIdMapping[$extension->getId()] = $extension;
             $extensionGraph[$extension->getId()] = $extension->getFlarumExtensionDependencies();
@@ -402,7 +401,7 @@ public static function resolveExtensionOrder($extensionList)
         }
 
         foreach ($extensionList as $extension) {
-            if (!array_key_exists($extension->getId(), $inDegreeCount)) {
+            if (! array_key_exists($extension->getId(), $inDegreeCount)) {
                 $inDegreeCount[$extension->getId()] = 0;
                 $pendingQueue[] = $extension->getId();
             }
@@ -416,7 +415,7 @@ public static function resolveExtensionOrder($extensionList)
                 $inDegreeCount[$dependency] -= 1;
 
                 if ($inDegreeCount[$dependency] === 0) {
-                    if (!array_key_exists($dependency, $extensionGraph)) {
+                    if (! array_key_exists($dependency, $extensionGraph)) {
                         // Missing Dependency
                         $missingDependencies[$activeNode] = array_merge(
                             Arr::get($missingDependencies, $activeNode, []),
@@ -430,10 +429,10 @@ public static function resolveExtensionOrder($extensionList)
         }
 
         $validOutput = array_filter($output, function ($extension) use ($missingDependencies) {
-            return !array_key_exists($extension, $missingDependencies);
+            return ! array_key_exists($extension, $missingDependencies);
         });
 
-        $validExtensions = array_reverse(array_map(function($extensionId) use ($extensionIdMapping) {
+        $validExtensions = array_reverse(array_map(function ($extensionId) use ($extensionIdMapping) {
             return $extensionIdMapping[$extensionId];
         }, $validOutput)); // Reversed as required by Kahn's algorithm.
 
diff --git a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
index 6cbae7fe39..e0ec68d991 100644
--- a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
+++ b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
@@ -28,7 +28,6 @@ public function setUp()
         $this->circular2 = new FakeExtension('circular2', ['circular1']);
     }
 
-
     /** @test */
     public function works_with_empty_set()
     {

From 6c686bb7eb0b0fc393dd513c99361a7796e98858 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 24 Jul 2020 15:09:09 -0400
Subject: [PATCH 07/32] Use require instead of dedicated field to get extension
 dependencies

---
 src/Extension/Extension.php        | 67 ++++++++++++++++++++----------
 src/Extension/ExtensionManager.php | 22 ++++++++--
 2 files changed, 62 insertions(+), 27 deletions(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index 881d6a2472..f3cc440bf6 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -15,6 +15,7 @@
 use Illuminate\Contracts\Container\Container;
 use Illuminate\Contracts\Support\Arrayable;
 use Illuminate\Support\Arr;
+use Illuminate\Support\Collection;
 use Illuminate\Support\Str;
 use League\Flysystem\Adapter\Local;
 use League\Flysystem\Filesystem;
@@ -51,6 +52,13 @@ class Extension implements Arrayable
         'jpg' => 'image/jpeg',
     ];
 
+    protected static function nameToId($name)
+    {
+        list($vendor, $package) = explode('/', $name);
+        $package = str_replace(['flarum-ext-', 'flarum-'], '', $package);
+        return "$vendor-$package";
+    }
+
     /**
      * Unique Id of the extension.
      *
@@ -74,6 +82,13 @@ class Extension implements Arrayable
      */
     protected $composerJson;
 
+    /**
+     * An array of extension ids for extension dependencies
+     *
+     * @var string[]
+     */
+    protected $dependencies;
+
     /**
      * Whether the extension is installed.
      *
@@ -104,9 +119,7 @@ public function __construct($path, $composerJson)
      */
     protected function assignId()
     {
-        list($vendor, $package) = explode('/', $this->name);
-        $package = str_replace(['flarum-ext-', 'flarum-'], '', $package);
-        $this->id = "$vendor-$package";
+        $this->id = static::nameToId($this->name);
     }
 
     public function extend(Container $app)
@@ -182,6 +195,22 @@ public function setVersion($version)
         return $this;
     }
 
+    /**
+     * Get the list of flarum extensions that this extension depends on
+     *
+     * @param array $lockJson: The json manifest of all installed php extensions
+     */
+    public function calculateDependencies($lockJson)
+    {
+        $this->extensionDependencies = (new Collection(Arr::get($this->composerJson, 'require', [])))
+            ->keys()
+            ->filter(function ($key) use ($lockJson) {
+                return array_key_exists($key, $lockJson);
+            })->map(function ($key) {
+                return static::nameToId($key);
+            })->toArray();
+    }
+
     /**
      * @return string
      */
@@ -204,11 +233,11 @@ public function getIcon()
             return $icon;
         }
 
-        $file = $this->path.'/'.$file;
+        $file = $this->path . '/' . $file;
 
         if (file_exists($file)) {
             $extension = pathinfo($file, PATHINFO_EXTENSION);
-            if (! array_key_exists($extension, self::LOGO_MIMETYPES)) {
+            if (!array_key_exists($extension, self::LOGO_MIMETYPES)) {
                 throw new \RuntimeException('Invalid image type');
             }
 
@@ -221,14 +250,6 @@ public function getIcon()
         return $icon;
     }
 
-    /**
-     * Get the list of flarum extensions that this extension depends on.
-     */
-    public function getFlarumExtensionDependencies()
-    {
-        return Arr::get($this->composerJson, 'extra.flarum-extension.dependencies.extensions', []);
-    }
-
     public function enable(Container $container)
     {
         foreach ($this->getLifecycleExtenders() as $extender) {
@@ -265,13 +286,13 @@ private function getExtenders(): array
     {
         $extenderFile = $this->getExtenderFile();
 
-        if (! $extenderFile) {
+        if (!$extenderFile) {
             return [];
         }
 
         $extenders = require $extenderFile;
 
-        if (! is_array($extenders)) {
+        if (!is_array($extenders)) {
             $extenders = [$extenders];
         }
 
@@ -318,17 +339,17 @@ private function getExtenderFile(): ?string
      */
     public function hasAssets()
     {
-        return realpath($this->path.'/assets/') !== false;
+        return realpath($this->path . '/assets/') !== false;
     }
 
     public function copyAssetsTo(FilesystemInterface $target)
     {
-        if (! $this->hasAssets()) {
+        if (!$this->hasAssets()) {
             return;
         }
 
         $mount = new MountManager([
-            'source' => $source = new Filesystem(new Local($this->getPath().'/assets')),
+            'source' => $source = new Filesystem(new Local($this->getPath() . '/assets')),
             'target' => $target,
         ]);
 
@@ -347,19 +368,19 @@ public function copyAssetsTo(FilesystemInterface $target)
      */
     public function hasMigrations()
     {
-        return realpath($this->path.'/migrations/') !== false;
+        return realpath($this->path . '/migrations/') !== false;
     }
 
     public function migrate(Migrator $migrator, $direction = 'up')
     {
-        if (! $this->hasMigrations()) {
+        if (!$this->hasMigrations()) {
             return;
         }
 
         if ($direction == 'up') {
-            return $migrator->run($this->getPath().'/migrations', $this);
+            return $migrator->run($this->getPath() . '/migrations', $this);
         } else {
-            return $migrator->reset($this->getPath().'/migrations', $this);
+            return $migrator->reset($this->getPath() . '/migrations', $this);
         }
     }
 
@@ -377,7 +398,7 @@ public function toArray()
             'icon'                  => $this->getIcon(),
             'hasAssets'             => $this->hasAssets(),
             'hasMigrations'         => $this->hasMigrations(),
-            'extensionDependencies' => $this->getFlarumExtensionDependencies(),
+            'extensionDependencies' => $this->extensionDependencies,
         ], $this->composerJson);
     }
 }
diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index e6fdd96639..8baa7b9c79 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -84,11 +84,20 @@ public function getExtensions()
             // Composer 2.0 changes the structure of the installed.json manifest
             $installed = $installed['packages'] ?? $installed;
 
+            // We calculate and store an associative copy of the json manifest
+            // to avoid an O(n * m) complexity when finding extension dependencies.
+            // Additionally, by only including flarum extensions, we know that
+            // anything present in this associative copy is a flarum extension, removing
+            // the need to check for it's type.
+            $associativeInstalled = [];
+
             foreach ($installed as $package) {
                 if (Arr::get($package, 'type') != 'flarum-extension' || empty(Arr::get($package, 'name'))) {
                     continue;
                 }
 
+                $associativeInstalled[Arr::get($package, 'name')] = $package;
+
                 $path = isset($package['install-path'])
                     ? $this->paths->vendor.'/composer/'.$package['install-path']
                     : $this->paths->vendor.'/'.Arr::get($package, 'name');
@@ -102,6 +111,11 @@ public function getExtensions()
 
                 $extensions->put($extension->getId(), $extension);
             }
+
+            foreach ($extensions as $extension) {
+                $extension->calculateDependencies($associativeInstalled);
+            }
+
             $this->extensions = $extensions->sortBy(function ($extension, $name) {
                 return $extension->composerJsonAttribute('extra.flarum-extension.title');
             });
@@ -136,7 +150,7 @@ public function enable($name)
 
         $missingDependencies = [];
         $enabled = $this->getEnabled();
-        foreach ($extension->getFlarumExtensionDependencies() as $dependency) {
+        foreach ($extension->extensionDependencies as $dependency) {
             if (! in_array($dependency, $enabled)) {
                 $missingDependencies[] = $dependency;
             }
@@ -181,7 +195,7 @@ public function disable($name)
         $dependentExtensions = [];
 
         foreach ($this->getEnabledExtensions() as $possibleDependent) {
-            foreach ($possibleDependent->getFlarumExtensionDependencies() as $dependency) {
+            foreach ($possibleDependent->extensionDependencies as $dependency) {
                 if ($dependency === $extension->getId()) {
                     $dependentExtensions[] = $dependency;
                     // No need to cycle through the rest of this extension's dependencies.
@@ -393,9 +407,9 @@ public static function resolveExtensionOrder($extensionList)
 
         foreach ($extensionList as $extension) {
             $extensionIdMapping[$extension->getId()] = $extension;
-            $extensionGraph[$extension->getId()] = $extension->getFlarumExtensionDependencies();
+            $extensionGraph[$extension->getId()] = $extension->extensionDependencies;
 
-            foreach ($extension->getFlarumExtensionDependencies() as $dependency) {
+            foreach ($extension->extensionDependencies as $dependency) {
                 $inDegreeCount[$dependency] = array_key_exists($dependency, $inDegreeCount) ? $inDegreeCount[$dependency] + 1 : 1;
             }
         }

From 787515d515124a482996ef2a06e07816881ded49 Mon Sep 17 00:00:00 2001
From: luceos <daniel+github@klabbers.email>
Date: Fri, 24 Jul 2020 19:10:02 +0000
Subject: [PATCH 08/32] Apply fixes from StyleCI

[ci skip] [skip ci]
---
 src/Extension/Extension.php | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index f3cc440bf6..57bac972f0 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -56,6 +56,7 @@ protected static function nameToId($name)
     {
         list($vendor, $package) = explode('/', $name);
         $package = str_replace(['flarum-ext-', 'flarum-'], '', $package);
+
         return "$vendor-$package";
     }
 
@@ -83,7 +84,7 @@ protected static function nameToId($name)
     protected $composerJson;
 
     /**
-     * An array of extension ids for extension dependencies
+     * An array of extension ids for extension dependencies.
      *
      * @var string[]
      */
@@ -196,7 +197,7 @@ public function setVersion($version)
     }
 
     /**
-     * Get the list of flarum extensions that this extension depends on
+     * Get the list of flarum extensions that this extension depends on.
      *
      * @param array $lockJson: The json manifest of all installed php extensions
      */
@@ -233,11 +234,11 @@ public function getIcon()
             return $icon;
         }
 
-        $file = $this->path . '/' . $file;
+        $file = $this->path.'/'.$file;
 
         if (file_exists($file)) {
             $extension = pathinfo($file, PATHINFO_EXTENSION);
-            if (!array_key_exists($extension, self::LOGO_MIMETYPES)) {
+            if (! array_key_exists($extension, self::LOGO_MIMETYPES)) {
                 throw new \RuntimeException('Invalid image type');
             }
 
@@ -286,13 +287,13 @@ private function getExtenders(): array
     {
         $extenderFile = $this->getExtenderFile();
 
-        if (!$extenderFile) {
+        if (! $extenderFile) {
             return [];
         }
 
         $extenders = require $extenderFile;
 
-        if (!is_array($extenders)) {
+        if (! is_array($extenders)) {
             $extenders = [$extenders];
         }
 
@@ -339,17 +340,17 @@ private function getExtenderFile(): ?string
      */
     public function hasAssets()
     {
-        return realpath($this->path . '/assets/') !== false;
+        return realpath($this->path.'/assets/') !== false;
     }
 
     public function copyAssetsTo(FilesystemInterface $target)
     {
-        if (!$this->hasAssets()) {
+        if (! $this->hasAssets()) {
             return;
         }
 
         $mount = new MountManager([
-            'source' => $source = new Filesystem(new Local($this->getPath() . '/assets')),
+            'source' => $source = new Filesystem(new Local($this->getPath().'/assets')),
             'target' => $target,
         ]);
 
@@ -368,19 +369,19 @@ public function copyAssetsTo(FilesystemInterface $target)
      */
     public function hasMigrations()
     {
-        return realpath($this->path . '/migrations/') !== false;
+        return realpath($this->path.'/migrations/') !== false;
     }
 
     public function migrate(Migrator $migrator, $direction = 'up')
     {
-        if (!$this->hasMigrations()) {
+        if (! $this->hasMigrations()) {
             return;
         }
 
         if ($direction == 'up') {
-            return $migrator->run($this->getPath() . '/migrations', $this);
+            return $migrator->run($this->getPath().'/migrations', $this);
         } else {
-            return $migrator->reset($this->getPath() . '/migrations', $this);
+            return $migrator->reset($this->getPath().'/migrations', $this);
         }
     }
 

From c374bafbfc513bc64f7533b693e4292483acd046 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 24 Jul 2020 15:22:15 -0400
Subject: [PATCH 09/32] Fix fake extension to not fail tests and be compliant

---
 .../Foundation/ExtensionDependencyResolutionTest.php  | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
index e0ec68d991..ef1d84a2b6 100644
--- a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
+++ b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
@@ -86,21 +86,16 @@ public function works_with_circular_dependencies()
 class FakeExtension
 {
     protected $id;
-    protected $dependencies;
+    public $extensionDependencies;
 
-    public function __construct($id, $dependencies)
+    public function __construct($id, $extensionDependencies)
     {
         $this->id = $id;
-        $this->dependencies = $dependencies;
+        $this->extensionDependencies = $extensionDependencies;
     }
 
     public function getId()
     {
         return $this->id;
     }
-
-    public function getFlarumExtensionDependencies()
-    {
-        return $this->dependencies;
-    }
 }

From 30ee917db673f477619208fb486e4671ea94fe39 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sun, 6 Sep 2020 17:26:15 -0400
Subject: [PATCH 10/32] Remove unnecessary import

---
 src/Extension/ExtensionManager.php | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 8baa7b9c79..9416bff583 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -15,7 +15,6 @@
 use Flarum\Extension\Event\Enabled;
 use Flarum\Extension\Event\Enabling;
 use Flarum\Extension\Event\Uninstalled;
-use Flarum\Extension\Exception\DependentExtensionsException;
 use Flarum\Foundation\Paths;
 use Flarum\Settings\SettingsRepositoryInterface;
 use Illuminate\Contracts\Container\Container;
@@ -205,7 +204,7 @@ public function disable($name)
         }
 
         if (! empty($dependentExtensions)) {
-            throw new DependentExtensionsException($extension, $dependentExtensions);
+            throw new Exception\DependentExtensionsException($extension, $dependentExtensions);
         }
 
         $this->dispatcher->dispatch(new Disabling($extension));

From fec6ff357bb4df2c85c9779b1b79ff2fa252b820 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sun, 6 Sep 2020 17:26:38 -0400
Subject: [PATCH 11/32] Fix constructor, remove KnownError since we'll need a
 custom handler

---
 .../Exception/DependentExtensionsException.php   | 10 +++-------
 .../Exception/MissingDependenciesException.php   | 16 ++++++----------
 2 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/src/Extension/Exception/DependentExtensionsException.php b/src/Extension/Exception/DependentExtensionsException.php
index a906add1c3..7ac8add3ce 100644
--- a/src/Extension/Exception/DependentExtensionsException.php
+++ b/src/Extension/Exception/DependentExtensionsException.php
@@ -11,9 +11,8 @@
 
 use Exception;
 use Flarum\Extension\Extension;
-use Flarum\Foundation\KnownError;
 
-class DependentExtensionsException extends Exception implements KnownError
+class DependentExtensionsException extends Exception
 {
     public $extension;
     public $dependent_extensions;
@@ -25,11 +24,8 @@ class DependentExtensionsException extends Exception implements KnownError
     public function __construct(Extension $extension, array $dependent_extensions = [])
     {
         $this->extension = $extension;
-        $this->$dependent_extensions = $dependent_extensions;
-    }
+        $this->dependent_extensions = $dependent_extensions;
 
-    public function getType(): string
-    {
-        return 'dependent_extensions';
+        parent::__construct(implode("\n", $dependent_extensions));
     }
 }
diff --git a/src/Extension/Exception/MissingDependenciesException.php b/src/Extension/Exception/MissingDependenciesException.php
index f3216df8a1..836775ad1a 100644
--- a/src/Extension/Exception/MissingDependenciesException.php
+++ b/src/Extension/Exception/MissingDependenciesException.php
@@ -11,25 +11,21 @@
 
 use Exception;
 use Flarum\Extension\Extension;
-use Flarum\Foundation\KnownError;
 
-class MissingDependenciesException extends Exception implements KnownError
+class MissingDependenciesException extends Exception
 {
     public $extension;
-    public $flarum_dependencies;
+    public $missing_dependencies;
 
     /**
      * @param $extension: The extension we are attempting to activate.
-     * @param $flarum_dependencies: Extension IDs of the missing flarum extension dependencies for this extension
+     * @param $missing_dependencies: Extension IDs of the missing flarum extension dependencies for this extension
      */
-    public function __construct(Extension $extension, array $flarum_dependencies = [])
+    public function __construct(Extension $extension, array $missing_dependencies = null)
     {
         $this->extension = $extension;
-        $this->$flarum_dependencies = $flarum_dependencies;
-    }
+        $this->missing_dependencies = $missing_dependencies;
 
-    public function getType(): string
-    {
-        return 'missing_dependencies';
+        parent::__construct(implode("\n", $missing_dependencies));
     }
 }

From 54a35b4173b726bb12f8a790e281dc789a410362 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sun, 6 Sep 2020 17:26:58 -0400
Subject: [PATCH 12/32] Add custom handlers for dependency exceptions

---
 .../DependentExtensionsExceptionHandler.php   | 34 +++++++++++++++++++
 .../MissingDependenciesExceptionHandler.php   | 34 +++++++++++++++++++
 src/Foundation/ErrorServiceProvider.php       |  6 ++++
 3 files changed, 74 insertions(+)
 create mode 100644 src/Extension/Exception/DependentExtensionsExceptionHandler.php
 create mode 100644 src/Extension/Exception/MissingDependenciesExceptionHandler.php

diff --git a/src/Extension/Exception/DependentExtensionsExceptionHandler.php b/src/Extension/Exception/DependentExtensionsExceptionHandler.php
new file mode 100644
index 0000000000..4dd3e0e583
--- /dev/null
+++ b/src/Extension/Exception/DependentExtensionsExceptionHandler.php
@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Flarum\Foundation\ErrorHandling\HandledError;
+
+class DependentExtensionsExceptionHandler
+{
+    public function handle(DependentExtensionsException $e): HandledError
+    {
+        return (new HandledError(
+            $e,
+            'dependent_extensions',
+            409
+        ))->withDetails($this->errorDetails($e));
+    }
+
+    protected function errorDetails(DependentExtensionsException $e): array
+    {
+        return [
+            [
+                'extension' => $e->extension->getId(),
+                'dependent_dependencies' => $e->dependent_dependencies
+            ]
+        ];
+    }
+}
diff --git a/src/Extension/Exception/MissingDependenciesExceptionHandler.php b/src/Extension/Exception/MissingDependenciesExceptionHandler.php
new file mode 100644
index 0000000000..e0c28a78e3
--- /dev/null
+++ b/src/Extension/Exception/MissingDependenciesExceptionHandler.php
@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Flarum\Foundation\ErrorHandling\HandledError;
+
+class MissingDependenciesExceptionHandler
+{
+    public function handle(MissingDependenciesException $e): HandledError
+    {
+        return (new HandledError(
+            $e,
+            'missing_dependencies',
+            409
+        ))->withDetails($this->errorDetails($e));
+    }
+
+    protected function errorDetails(MissingDependenciesException $e): array
+    {
+        return [
+            [
+                'extension' => $e->extension->getId(),
+                'missing_dependencies' => $e->missing_dependencies
+            ]
+        ];
+    }
+}
diff --git a/src/Foundation/ErrorServiceProvider.php b/src/Foundation/ErrorServiceProvider.php
index 58c827f7fe..02483841de 100644
--- a/src/Foundation/ErrorServiceProvider.php
+++ b/src/Foundation/ErrorServiceProvider.php
@@ -9,6 +9,10 @@
 
 namespace Flarum\Foundation;
 
+use Flarum\Extension\Exception\DependentExtensionsException;
+use Flarum\Extension\Exception\DependentExtensionsExceptionHandler;
+use Flarum\Extension\Exception\MissingDependenciesException;
+use Flarum\Extension\Exception\MissingDependenciesExceptionHandler;
 use Flarum\Foundation\ErrorHandling\ExceptionHandler;
 use Flarum\Foundation\ErrorHandling\LogReporter;
 use Flarum\Foundation\ErrorHandling\Registry;
@@ -57,6 +61,8 @@ public function register()
             return [
                 IlluminateValidationException::class => ExceptionHandler\IlluminateValidationExceptionHandler::class,
                 ValidationException::class => ExceptionHandler\ValidationExceptionHandler::class,
+                DependentExtensionsException::class => DependentExtensionsExceptionHandler::class,
+                MissingDependenciesException::class => MissingDependenciesExceptionHandler::class,
             ];
         });
 

From 2e4ebefd2a089e1e2140f8615a73412c394ac743 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sun, 6 Sep 2020 17:49:16 -0400
Subject: [PATCH 13/32] Standardize return format

---
 src/Extension/Exception/DependentExtensionsExceptionHandler.php | 2 +-
 src/Extension/Exception/MissingDependenciesExceptionHandler.php | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Extension/Exception/DependentExtensionsExceptionHandler.php b/src/Extension/Exception/DependentExtensionsExceptionHandler.php
index 4dd3e0e583..55241ccc71 100644
--- a/src/Extension/Exception/DependentExtensionsExceptionHandler.php
+++ b/src/Extension/Exception/DependentExtensionsExceptionHandler.php
@@ -27,7 +27,7 @@ protected function errorDetails(DependentExtensionsException $e): array
         return [
             [
                 'extension' => $e->extension->getId(),
-                'dependent_dependencies' => $e->dependent_dependencies
+                'extensions' => $e->dependent_extensions
             ]
         ];
     }
diff --git a/src/Extension/Exception/MissingDependenciesExceptionHandler.php b/src/Extension/Exception/MissingDependenciesExceptionHandler.php
index e0c28a78e3..995e3de683 100644
--- a/src/Extension/Exception/MissingDependenciesExceptionHandler.php
+++ b/src/Extension/Exception/MissingDependenciesExceptionHandler.php
@@ -27,7 +27,7 @@ protected function errorDetails(MissingDependenciesException $e): array
         return [
             [
                 'extension' => $e->extension->getId(),
-                'missing_dependencies' => $e->missing_dependencies
+                'extensions' => $e->missing_dependencies
             ]
         ];
     }

From d12fe5bd2b07ef5a40f11df0c2aebcaa9c8c66fc Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sun, 6 Sep 2020 17:49:31 -0400
Subject: [PATCH 14/32] Add frontend error handler for admin dashboard

---
 js/src/admin/components/ExtensionsPage.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/js/src/admin/components/ExtensionsPage.js b/js/src/admin/components/ExtensionsPage.js
index 5a50fea6ea..d4523f4378 100644
--- a/js/src/admin/components/ExtensionsPage.js
+++ b/js/src/admin/components/ExtensionsPage.js
@@ -123,6 +123,7 @@ export default class ExtensionsPage extends Page {
         url: app.forum.attribute('apiUrl') + '/extensions/' + id,
         method: 'PATCH',
         body: { enabled: !enabled },
+        errorHandler: this.onerror.bind(this),
       })
       .then(() => {
         if (!enabled) localStorage.setItem('enabledExtension', id);
@@ -131,4 +132,18 @@ export default class ExtensionsPage extends Page {
 
     app.modal.show(LoadingModal);
   }
+
+  onerror(e) {
+    app.modal.close();
+
+    const error = JSON.parse(e.responseText).errors[0];
+
+    app.alerts.show(
+      app.translator.trans(`core.lib.error.${error.code}_message`, {
+        extension: error.extension,
+        extensions: error.extensions.join(', '),
+      }),
+      { type: 'error' }
+    );
+  }
 }

From 6e4b8674c4b8c14d5da7003a4c7f28824d380b70 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sun, 6 Sep 2020 17:58:38 -0400
Subject: [PATCH 15/32] Fix dependentExtensions saving the wrong thing

---
 src/Extension/ExtensionManager.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 9416bff583..155c598bf9 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -196,7 +196,7 @@ public function disable($name)
         foreach ($this->getEnabledExtensions() as $possibleDependent) {
             foreach ($possibleDependent->extensionDependencies as $dependency) {
                 if ($dependency === $extension->getId()) {
-                    $dependentExtensions[] = $dependency;
+                    $dependentExtensions[] = $possibleDependent->getId();
                     // No need to cycle through the rest of this extension's dependencies.
                     break;
                 }

From 7b405f0708a54140341d1cecac40d16c9cc614a5 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <38059171+askvortsov1@users.noreply.github.com>
Date: Sun, 6 Sep 2020 18:37:15 -0400
Subject: [PATCH 16/32] Update
 src/Extension/Exception/DependentExtensionsException.php
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Daniël Klabbers <luceos@users.noreply.github.com>
---
 src/Extension/Exception/DependentExtensionsException.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Extension/Exception/DependentExtensionsException.php b/src/Extension/Exception/DependentExtensionsException.php
index 7ac8add3ce..471a8000ed 100644
--- a/src/Extension/Exception/DependentExtensionsException.php
+++ b/src/Extension/Exception/DependentExtensionsException.php
@@ -21,7 +21,7 @@ class DependentExtensionsException extends Exception
      * @param $extension: The extension we are attempting to activate.
      * @param $dependent_extensions: Extension IDs of the Flarum extensions that depend on this extension
      */
-    public function __construct(Extension $extension, array $dependent_extensions = [])
+    public function __construct(Extension $extension, array $dependent_extensions)
     {
         $this->extension = $extension;
         $this->dependent_extensions = $dependent_extensions;

From 39ca931632a055ec7d8c0c823251d13d84dca01b Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Thu, 24 Sep 2020 17:54:49 -0400
Subject: [PATCH 17/32] Update for new alerts signature

---
 js/src/admin/components/ExtensionsPage.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/js/src/admin/components/ExtensionsPage.js b/js/src/admin/components/ExtensionsPage.js
index d4523f4378..6f92f385b8 100644
--- a/js/src/admin/components/ExtensionsPage.js
+++ b/js/src/admin/components/ExtensionsPage.js
@@ -139,11 +139,11 @@ export default class ExtensionsPage extends Page {
     const error = JSON.parse(e.responseText).errors[0];
 
     app.alerts.show(
+      { type: 'error' },
       app.translator.trans(`core.lib.error.${error.code}_message`, {
         extension: error.extension,
         extensions: error.extensions.join(', '),
-      }),
-      { type: 'error' }
+      })
     );
   }
 }

From 7be3c1f593cf5d8641f1aa232543701aae6a1080 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Thu, 24 Sep 2020 17:55:08 -0400
Subject: [PATCH 18/32] Add more tests for dependency resolution

---
 .../ExtensionDependencyResolutionTest.php     | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
index ef1d84a2b6..3f89b2162b 100644
--- a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
+++ b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
@@ -54,6 +54,34 @@ public function works_with_proper_data()
         $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
     }
 
+    /** @test */
+    public function works_with_proper_data_in_different_order()
+    {
+        $exts = [$this->help, $this->categories, $this->tagBackgrounds, $this->tags, $this->something];
+
+        $expected = [
+            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
+            'missingDependencies' => [],
+            'circularDependencies' => [],
+        ];
+
+        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
+    }
+
+    /** @test */
+    public function works_with_proper_data_in_yet_another_order()
+    {
+        $exts = [$this->something, $this->tagBackgrounds, $this->help, $this->categories, $this->tags];
+
+        $expected = [
+            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
+            'missingDependencies' => [],
+            'circularDependencies' => [],
+        ];
+
+        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
+    }
+
     /** @test */
     public function works_with_missing_dependencies()
     {

From d32bafcdc5179b24c7a5f504f066ab989ced7f27 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sat, 26 Sep 2020 12:59:49 -0400
Subject: [PATCH 19/32] Remove dependency resolution portion

---
 src/Extension/ExtensionManager.php            |  86 +-----------
 .../ExtensionDependencyResolutionTest.php     | 129 ------------------
 2 files changed, 1 insertion(+), 214 deletions(-)
 delete mode 100644 tests/unit/Foundation/ExtensionDependencyResolutionTest.php

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 155c598bf9..6308e3f74b 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -338,9 +338,7 @@ public function getEnabledExtensions()
      */
     public function extend(Container $app)
     {
-        $enabled = static::resolveExtensionOrder($this->getEnabledExtensions());
-
-        foreach ($enabled['valid'] as $extension) {
+        foreach ($this->getEnabledExtensions() as $extension) {
             $extension->extend($app);
         }
     }
@@ -379,86 +377,4 @@ public function isEnabled($extension)
 
         return isset($enabled[$extension]);
     }
-
-    /**
-     * Sort a list of extensions so that they are properly resolved in respect to order.
-     * Effectively just topological sorting.
-     *
-     * @param $extensionList: an array of \Flarum\Extension\Extension objects
-     *
-     * @return array with 2 keys: 'extensions' points to an ordered array of \Flarum\Extension\Extension
-     *                            'missingDependencies' points to an associative array of extensions that could not be resolved due
-     *                                to missing dependencies, in the format extension id => array of missing dependency IDs.
-     *                            'circularDependencies' points to an array of extensions ids of extensions
-     *                                that cannot be processed due to circular dependencies
-     */
-    public static function resolveExtensionOrder($extensionList)
-    {
-        $extensionIdMapping = []; // Used for caching so we don't rerun ->getExtensions every time.
-
-        // This is an implementation of Kahn's Algorithm (https://dl.acm.org/doi/10.1145/368996.369025)
-        $extensionGraph = [];
-        $output = [];
-        $missingDependencies = []; // Extensions are invalid if they are missing dependencies, or have circular dependencies.
-        $circularDependencies = [];
-        $pendingQueue = [];
-        $inDegreeCount = []; // How many extensions are dependent on a given extension?
-
-        foreach ($extensionList as $extension) {
-            $extensionIdMapping[$extension->getId()] = $extension;
-            $extensionGraph[$extension->getId()] = $extension->extensionDependencies;
-
-            foreach ($extension->extensionDependencies as $dependency) {
-                $inDegreeCount[$dependency] = array_key_exists($dependency, $inDegreeCount) ? $inDegreeCount[$dependency] + 1 : 1;
-            }
-        }
-
-        foreach ($extensionList as $extension) {
-            if (! array_key_exists($extension->getId(), $inDegreeCount)) {
-                $inDegreeCount[$extension->getId()] = 0;
-                $pendingQueue[] = $extension->getId();
-            }
-        }
-
-        while (! empty($pendingQueue)) {
-            $activeNode = array_shift($pendingQueue);
-            $output[] = $activeNode;
-
-            foreach ($extensionGraph[$activeNode] as $dependency) {
-                $inDegreeCount[$dependency] -= 1;
-
-                if ($inDegreeCount[$dependency] === 0) {
-                    if (! array_key_exists($dependency, $extensionGraph)) {
-                        // Missing Dependency
-                        $missingDependencies[$activeNode] = array_merge(
-                            Arr::get($missingDependencies, $activeNode, []),
-                            [$dependency]
-                        );
-                    } else {
-                        $pendingQueue[] = $dependency;
-                    }
-                }
-            }
-        }
-
-        $validOutput = array_filter($output, function ($extension) use ($missingDependencies) {
-            return ! array_key_exists($extension, $missingDependencies);
-        });
-
-        $validExtensions = array_reverse(array_map(function ($extensionId) use ($extensionIdMapping) {
-            return $extensionIdMapping[$extensionId];
-        }, $validOutput)); // Reversed as required by Kahn's algorithm.
-
-        foreach ($inDegreeCount as $id => $count) {
-            if ($count != 0) {
-                $circularDependencies[] = $id;
-            }
-        }
-
-        return [
-            'valid' => $validExtensions,
-            'missingDependencies' => $missingDependencies,
-            'circularDependencies' => $circularDependencies
-        ];
-    }
 }
diff --git a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php b/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
deleted file mode 100644
index 3f89b2162b..0000000000
--- a/tests/unit/Foundation/ExtensionDependencyResolutionTest.php
+++ /dev/null
@@ -1,129 +0,0 @@
-<?php
-
-/*
- * This file is part of Flarum.
- *
- * For detailed copyright and license information, please view the
- * LICENSE file that was distributed with this source code.
- */
-
-namespace Flarum\Tests\unit\Foundation;
-
-use Flarum\Extension\ExtensionManager;
-use Flarum\Tests\unit\TestCase;
-
-class ExtensionDependencyResolutionTest extends TestCase
-{
-    public function setUp()
-    {
-        parent::setUp();
-
-        $this->tags = new FakeExtension('flarum-tags', []);
-        $this->categories = new FakeExtension('flarum-categories', ['flarum-tags', 'flarum-tag-backgrounds']);
-        $this->tagBackgrounds = new FakeExtension('flarum-tag-backgrounds', ['flarum-tags']);
-        $this->something = new FakeExtension('flarum-something', ['flarum-categories', 'flarum-help']);
-        $this->help = new FakeExtension('flarum-help', []);
-        $this->missing = new FakeExtension('flarum-missing', ['this-does-not-exist', 'flarum-tags', 'also-not-exists']);
-        $this->circular1 = new FakeExtension('circular1', ['circular2']);
-        $this->circular2 = new FakeExtension('circular2', ['circular1']);
-    }
-
-    /** @test */
-    public function works_with_empty_set()
-    {
-        $expected = [
-            'valid' => [],
-            'missingDependencies' => [],
-            'circularDependencies' => [],
-        ];
-
-        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder([]));
-    }
-
-    /** @test */
-    public function works_with_proper_data()
-    {
-        $exts = [$this->tags, $this->categories, $this->tagBackgrounds, $this->something, $this->help];
-
-        $expected = [
-            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
-            'missingDependencies' => [],
-            'circularDependencies' => [],
-        ];
-
-        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
-    }
-
-    /** @test */
-    public function works_with_proper_data_in_different_order()
-    {
-        $exts = [$this->help, $this->categories, $this->tagBackgrounds, $this->tags, $this->something];
-
-        $expected = [
-            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
-            'missingDependencies' => [],
-            'circularDependencies' => [],
-        ];
-
-        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
-    }
-
-    /** @test */
-    public function works_with_proper_data_in_yet_another_order()
-    {
-        $exts = [$this->something, $this->tagBackgrounds, $this->help, $this->categories, $this->tags];
-
-        $expected = [
-            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
-            'missingDependencies' => [],
-            'circularDependencies' => [],
-        ];
-
-        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
-    }
-
-    /** @test */
-    public function works_with_missing_dependencies()
-    {
-        $exts = [$this->tags, $this->categories, $this->tagBackgrounds, $this->something, $this->help, $this->missing];
-
-        $expected = [
-            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
-            'missingDependencies' => ['flarum-missing' => ['this-does-not-exist', 'also-not-exists']],
-            'circularDependencies' => [],
-        ];
-
-        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
-    }
-
-    /** @test */
-    public function works_with_circular_dependencies()
-    {
-        $exts = [$this->tags, $this->categories, $this->tagBackgrounds, $this->something, $this->help, $this->circular1, $this->circular2];
-
-        $expected = [
-            'valid' => [$this->tags, $this->tagBackgrounds, $this->help, $this->categories, $this->something],
-            'missingDependencies' => [],
-            'circularDependencies' => ['circular2', 'circular1'],
-        ];
-
-        $this->assertEquals($expected, ExtensionManager::resolveExtensionOrder($exts));
-    }
-}
-
-class FakeExtension
-{
-    protected $id;
-    public $extensionDependencies;
-
-    public function __construct($id, $extensionDependencies)
-    {
-        $this->id = $id;
-        $this->extensionDependencies = $extensionDependencies;
-    }
-
-    public function getId()
-    {
-        return $this->id;
-    }
-}

From 8becd7ce66db4c025fb0906f5b41efe1f986d036 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Sat, 26 Sep 2020 13:54:10 -0400
Subject: [PATCH 20/32] Store a set of installed extension composer names
 instead of an associative array to their package.jsons to save memory

---
 src/Extension/ExtensionManager.php | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 6308e3f74b..be9099d344 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -83,19 +83,18 @@ public function getExtensions()
             // Composer 2.0 changes the structure of the installed.json manifest
             $installed = $installed['packages'] ?? $installed;
 
-            // We calculate and store an associative copy of the json manifest
+            // We calculate and store a set of installed extension IDs (associative array with null keys)
             // to avoid an O(n * m) complexity when finding extension dependencies.
-            // Additionally, by only including flarum extensions, we know that
-            // anything present in this associative copy is a flarum extension, removing
-            // the need to check for it's type.
-            $associativeInstalled = [];
+            // By only including flarum extensions, we know that anything present in this associative copy
+            // is a flarum extension, removing the need to check for it's type.
+            $installedSet = [];
 
             foreach ($installed as $package) {
                 if (Arr::get($package, 'type') != 'flarum-extension' || empty(Arr::get($package, 'name'))) {
                     continue;
                 }
 
-                $associativeInstalled[Arr::get($package, 'name')] = $package;
+                $installedSet[Arr::get($package, 'name')] = null;
 
                 $path = isset($package['install-path'])
                     ? $this->paths->vendor.'/composer/'.$package['install-path']
@@ -112,7 +111,7 @@ public function getExtensions()
             }
 
             foreach ($extensions as $extension) {
-                $extension->calculateDependencies($associativeInstalled);
+                $extension->calculateDependencies($installedSet);
             }
 
             $this->extensions = $extensions->sortBy(function ($extension, $name) {

From ebe0107b20bf3bf7c7b78546fd3020368c4be12b Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Wed, 30 Sep 2020 15:45:12 -0400
Subject: [PATCH 21/32] Improve explanation for installedSet, put its values as
 true, not null

---
 src/Extension/ExtensionManager.php | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index be9099d344..3a71415d51 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -84,9 +84,11 @@ public function getExtensions()
             $installed = $installed['packages'] ?? $installed;
 
             // We calculate and store a set of installed extension IDs (associative array with null keys)
-            // to avoid an O(n * m) complexity when finding extension dependencies.
+            // to avoid O(n * m) complexity when finding extension dependencies.
             // By only including flarum extensions, we know that anything present in this associative copy
             // is a flarum extension, removing the need to check for it's type.
+            // We store the installed flarum extensions as keys, not values, of this array
+            // so that we have constant lookup time.
             $installedSet = [];
 
             foreach ($installed as $package) {
@@ -94,7 +96,7 @@ public function getExtensions()
                     continue;
                 }
 
-                $installedSet[Arr::get($package, 'name')] = null;
+                $installedSet[Arr::get($package, 'name')] = true;
 
                 $path = isset($package['install-path'])
                     ? $this->paths->vendor.'/composer/'.$package['install-path']
@@ -110,6 +112,8 @@ public function getExtensions()
                 $extensions->put($extension->getId(), $extension);
             }
 
+            $installedSet = $extensions->pluck('name')->toArray();
+
             foreach ($extensions as $extension) {
                 $extension->calculateDependencies($installedSet);
             }

From 3fa2cddd28ba08bfedd4f0e308d6aaa53e0283e0 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 15:05:12 -0400
Subject: [PATCH 22/32] Fix comments

---
 src/Extension/ExtensionManager.php | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 3a71415d51..3016a32068 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -83,8 +83,8 @@ public function getExtensions()
             // Composer 2.0 changes the structure of the installed.json manifest
             $installed = $installed['packages'] ?? $installed;
 
-            // We calculate and store a set of installed extension IDs (associative array with null keys)
-            // to avoid O(n * m) complexity when finding extension dependencies.
+            // We calculate and store a set of installed extension IDs (associative array with true keys)
+            // to speed up figuring what is and isn't a flarum extension later on.
             // By only including flarum extensions, we know that anything present in this associative copy
             // is a flarum extension, removing the need to check for it's type.
             // We store the installed flarum extensions as keys, not values, of this array
@@ -198,9 +198,10 @@ public function disable($name)
 
         foreach ($this->getEnabledExtensions() as $possibleDependent) {
             foreach ($possibleDependent->extensionDependencies as $dependency) {
+                // We check all enabled extensions. For each of them, if any depend on the extension
+                // we're disabling, we add it to the list and move onto the next one.
                 if ($dependency === $extension->getId()) {
                     $dependentExtensions[] = $possibleDependent->getId();
-                    // No need to cycle through the rest of this extension's dependencies.
                     break;
                 }
             }

From e1d63784b2f26ab9c4ba48b6bc6ecb050d51b94e Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 15:42:41 -0400
Subject: [PATCH 23/32] Get rid of the $installedSet mess, use $extensions to
 check what is/isn't a flarum extension instead.

---
 src/Extension/Extension.php        | 10 ++++++----
 src/Extension/ExtensionManager.php | 21 ++++++---------------
 2 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index 57bac972f0..8329c5fb15 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -199,14 +199,16 @@ public function setVersion($version)
     /**
      * Get the list of flarum extensions that this extension depends on.
      *
-     * @param array $lockJson: The json manifest of all installed php extensions
+     * @param array $extensionSet: An associative array where keys are the composer package names
+     *                             of installed extensions. Used to figure out which dependencies
+     *                             are flarum extensions.
      */
-    public function calculateDependencies($lockJson)
+    public function calculateDependencies($extensionSet)
     {
         $this->extensionDependencies = (new Collection(Arr::get($this->composerJson, 'require', [])))
             ->keys()
-            ->filter(function ($key) use ($lockJson) {
-                return array_key_exists($key, $lockJson);
+            ->filter(function ($key) use ($extensionSet) {
+                return array_key_exists($key, $extensionSet);
             })->map(function ($key) {
                 return static::nameToId($key);
             })->toArray();
diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 3016a32068..988e7a46b6 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -83,21 +83,11 @@ public function getExtensions()
             // Composer 2.0 changes the structure of the installed.json manifest
             $installed = $installed['packages'] ?? $installed;
 
-            // We calculate and store a set of installed extension IDs (associative array with true keys)
-            // to speed up figuring what is and isn't a flarum extension later on.
-            // By only including flarum extensions, we know that anything present in this associative copy
-            // is a flarum extension, removing the need to check for it's type.
-            // We store the installed flarum extensions as keys, not values, of this array
-            // so that we have constant lookup time.
-            $installedSet = [];
-
             foreach ($installed as $package) {
                 if (Arr::get($package, 'type') != 'flarum-extension' || empty(Arr::get($package, 'name'))) {
                     continue;
                 }
 
-                $installedSet[Arr::get($package, 'name')] = true;
-
                 $path = isset($package['install-path'])
                     ? $this->paths->vendor.'/composer/'.$package['install-path']
                     : $this->paths->vendor.'/'.Arr::get($package, 'name');
@@ -109,16 +99,17 @@ public function getExtensions()
                 $extension->setInstalled(true);
                 $extension->setVersion(Arr::get($package, 'version'));
 
-                $extensions->put($extension->getId(), $extension);
+                // We use the composer package name as the key so that:
+                //   1. We don't have naming collisions
+                //   2. We can use it for constant time lookups in `calculateDependencies`
+                $extensions->put(Arr::get($package, 'name'), $extension);
             }
 
-            $installedSet = $extensions->pluck('name')->toArray();
-
             foreach ($extensions as $extension) {
-                $extension->calculateDependencies($installedSet);
+                $extension->calculateDependencies($extensions);
             }
 
-            $this->extensions = $extensions->sortBy(function ($extension, $name) {
+            $this->extensions = $extensions->sortBy(function ($extension) {
                 return $extension->composerJsonAttribute('extra.flarum-extension.title');
             });
         }

From 7acf52b55c0ed3b6073a8028a40cb1db4f6c176b Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 15:55:13 -0400
Subject: [PATCH 24/32] Go back to using $installedSet to store composer
 package names for installed extensions

---
 src/Extension/ExtensionManager.php | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 988e7a46b6..5e0b3e5644 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -83,11 +83,18 @@ public function getExtensions()
             // Composer 2.0 changes the structure of the installed.json manifest
             $installed = $installed['packages'] ?? $installed;
 
+            // We calculate and store a set of composer package names for all installed Flarum extensions,
+            // so we know what is and isn't a flarum extension in `calculateDependencies`.
+            // Using keys of an associative array allows us to do these checks in constant time.
+            $installedSet = [];
+
             foreach ($installed as $package) {
                 if (Arr::get($package, 'type') != 'flarum-extension' || empty(Arr::get($package, 'name'))) {
                     continue;
                 }
 
+                $installedSet[Arr::get($package, 'name')] = true;
+
                 $path = isset($package['install-path'])
                     ? $this->paths->vendor.'/composer/'.$package['install-path']
                     : $this->paths->vendor.'/'.Arr::get($package, 'name');
@@ -99,14 +106,11 @@ public function getExtensions()
                 $extension->setInstalled(true);
                 $extension->setVersion(Arr::get($package, 'version'));
 
-                // We use the composer package name as the key so that:
-                //   1. We don't have naming collisions
-                //   2. We can use it for constant time lookups in `calculateDependencies`
-                $extensions->put(Arr::get($package, 'name'), $extension);
+                $extensions->put($extension->getId(), $extension);
             }
 
             foreach ($extensions as $extension) {
-                $extension->calculateDependencies($extensions);
+                $extension->calculateDependencies($installedSet);
             }
 
             $this->extensions = $extensions->sortBy(function ($extension) {

From 58477b534424515c80fa0155b9ac118a6fb68242 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 16:22:06 -0400
Subject: [PATCH 25/32] Code cleanup

- Make extensionDependencies protected, call through encapsulated method
- The dependency exceptions now store arrays of extensions, not arrays of extension ids.
- Improve documentation
---
 .../DependentExtensionsException.php          | 21 ++++++++-
 .../DependentExtensionsExceptionHandler.php   |  2 +-
 .../MissingDependenciesException.php          | 19 +++++++-
 .../MissingDependenciesExceptionHandler.php   |  2 +-
 src/Extension/Extension.php                   | 19 ++++++--
 src/Extension/ExtensionManager.php            | 45 ++++++++-----------
 6 files changed, 72 insertions(+), 36 deletions(-)

diff --git a/src/Extension/Exception/DependentExtensionsException.php b/src/Extension/Exception/DependentExtensionsException.php
index 471a8000ed..847f4e6325 100644
--- a/src/Extension/Exception/DependentExtensionsException.php
+++ b/src/Extension/Exception/DependentExtensionsException.php
@@ -12,14 +12,19 @@
 use Exception;
 use Flarum\Extension\Extension;
 
+
+/**
+ * This exception is thrown when someone attempts to disable an extension
+ * that other enabled extensions depend on.
+ */
 class DependentExtensionsException extends Exception
 {
     public $extension;
     public $dependent_extensions;
 
     /**
-     * @param $extension: The extension we are attempting to activate.
-     * @param $dependent_extensions: Extension IDs of the Flarum extensions that depend on this extension
+     * @param $extension: The extension we are attempting to disable.
+     * @param $dependent_extensions: Enabled Flarum extensions that depend on this extension.
      */
     public function __construct(Extension $extension, array $dependent_extensions)
     {
@@ -28,4 +33,16 @@ public function __construct(Extension $extension, array $dependent_extensions)
 
         parent::__construct(implode("\n", $dependent_extensions));
     }
+
+    /**
+     * Get array of IDs for extensions that depend on this extension.
+     *
+     * @return array
+     */
+    public function getDependentExtensionIds()
+    {
+        return array_map(function (Extension $extension) {
+            return $extension->getId();
+        }, $this->dependent_extensions);
+    }
 }
diff --git a/src/Extension/Exception/DependentExtensionsExceptionHandler.php b/src/Extension/Exception/DependentExtensionsExceptionHandler.php
index 55241ccc71..a8ad877274 100644
--- a/src/Extension/Exception/DependentExtensionsExceptionHandler.php
+++ b/src/Extension/Exception/DependentExtensionsExceptionHandler.php
@@ -27,7 +27,7 @@ protected function errorDetails(DependentExtensionsException $e): array
         return [
             [
                 'extension' => $e->extension->getId(),
-                'extensions' => $e->dependent_extensions
+                'extensions' => $e->getDependentExtensionIds(),
             ]
         ];
     }
diff --git a/src/Extension/Exception/MissingDependenciesException.php b/src/Extension/Exception/MissingDependenciesException.php
index 836775ad1a..ea2dbfd076 100644
--- a/src/Extension/Exception/MissingDependenciesException.php
+++ b/src/Extension/Exception/MissingDependenciesException.php
@@ -12,14 +12,18 @@
 use Exception;
 use Flarum\Extension\Extension;
 
+/**
+ * This exception is thrown when someone attempts to enable an extension
+ * whose Flarum extension dependencies are not all enabled.
+ */
 class MissingDependenciesException extends Exception
 {
     public $extension;
     public $missing_dependencies;
 
     /**
-     * @param $extension: The extension we are attempting to activate.
-     * @param $missing_dependencies: Extension IDs of the missing flarum extension dependencies for this extension
+     * @param $extension: The extension we are attempting to enable.
+     * @param $missing_dependencies: Extensions that this extension depends on, and are not enabled.
      */
     public function __construct(Extension $extension, array $missing_dependencies = null)
     {
@@ -28,4 +32,15 @@ public function __construct(Extension $extension, array $missing_dependencies =
 
         parent::__construct(implode("\n", $missing_dependencies));
     }
+
+    /**
+     * Get array of IDs for missing (disabled) extensions that this extension depends on.
+     *
+     * @return array
+     */
+    public function getMissingDependencyIds() {
+        return array_map(function(Extension $extension) {
+            return $extension->getId();
+        }, $this->missing_dependencies);
+    }
 }
diff --git a/src/Extension/Exception/MissingDependenciesExceptionHandler.php b/src/Extension/Exception/MissingDependenciesExceptionHandler.php
index 995e3de683..39f8980cc2 100644
--- a/src/Extension/Exception/MissingDependenciesExceptionHandler.php
+++ b/src/Extension/Exception/MissingDependenciesExceptionHandler.php
@@ -27,7 +27,7 @@ protected function errorDetails(MissingDependenciesException $e): array
         return [
             [
                 'extension' => $e->extension->getId(),
-                'extensions' => $e->missing_dependencies
+                'extensions' => $e->getMissingDependencyIds(),
             ]
         ];
     }
diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index 8329c5fb15..bf0ba5e8d1 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -69,6 +69,7 @@ protected static function nameToId($name)
      * @var string
      */
     protected $id;
+
     /**
      * The directory of this extension.
      *
@@ -84,11 +85,11 @@ protected static function nameToId($name)
     protected $composerJson;
 
     /**
-     * An array of extension ids for extension dependencies.
+     * The IDs of all Flarum extensions that this extension depends on.
      *
      * @var string[]
      */
-    protected $dependencies;
+    protected $extensionDependencies;
 
     /**
      * Whether the extension is installed.
@@ -285,6 +286,16 @@ public function getPath()
         return $this->path;
     }
 
+    /**
+     * The IDs of all Flarum extensions that this extension depends on.
+     *
+     * @return array
+     */
+    public function getExtensionDependencies()
+    {
+        return $this->extensionDependencies;
+    }
+
     private function getExtenders(): array
     {
         $extenderFile = $this->getExtenderFile();
@@ -397,11 +408,11 @@ public function toArray()
         return (array) array_merge([
             'id'                    => $this->getId(),
             'version'               => $this->getVersion(),
-            'path'                  => $this->path,
+            'path'                  => $this->getPath(),
             'icon'                  => $this->getIcon(),
             'hasAssets'             => $this->hasAssets(),
             'hasMigrations'         => $this->hasMigrations(),
-            'extensionDependencies' => $this->extensionDependencies,
+            'extensionDependencies' => $this->getExtensionDependencies(),
         ], $this->composerJson);
     }
 }
diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 5e0b3e5644..aa399531c7 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -74,11 +74,11 @@ public function __construct(
      */
     public function getExtensions()
     {
-        if (is_null($this->extensions) && $this->filesystem->exists($this->paths->vendor.'/composer/installed.json')) {
+        if (is_null($this->extensions) && $this->filesystem->exists($this->paths->vendor . '/composer/installed.json')) {
             $extensions = new Collection();
 
             // Load all packages installed by composer.
-            $installed = json_decode($this->filesystem->get($this->paths->vendor.'/composer/installed.json'), true);
+            $installed = json_decode($this->filesystem->get($this->paths->vendor . '/composer/installed.json'), true);
 
             // Composer 2.0 changes the structure of the installed.json manifest
             $installed = $installed['packages'] ?? $installed;
@@ -96,8 +96,8 @@ public function getExtensions()
                 $installedSet[Arr::get($package, 'name')] = true;
 
                 $path = isset($package['install-path'])
-                    ? $this->paths->vendor.'/composer/'.$package['install-path']
-                    : $this->paths->vendor.'/'.Arr::get($package, 'name');
+                    ? $this->paths->vendor . '/composer/' . $package['install-path']
+                    : $this->paths->vendor . '/' . Arr::get($package, 'name');
 
                 // Instantiates an Extension object using the package path and composer.json file.
                 $extension = new Extension($path, $package);
@@ -113,7 +113,7 @@ public function getExtensions()
                 $extension->calculateDependencies($installedSet);
             }
 
-            $this->extensions = $extensions->sortBy(function ($extension) {
+            $this->extensions = $extensions->sortBy(function ($extension, $name) {
                 return $extension->composerJsonAttribute('extra.flarum-extension.title');
             });
         }
@@ -146,28 +146,26 @@ public function enable($name)
         $extension = $this->getExtension($name);
 
         $missingDependencies = [];
-        $enabled = $this->getEnabled();
-        foreach ($extension->extensionDependencies as $dependency) {
-            if (! in_array($dependency, $enabled)) {
-                $missingDependencies[] = $dependency;
+        $enabledIds = $this->getEnabled();
+        foreach ($extension->getExtensionDependencies() as $dependencyId) {
+            if (!in_array($dependencyId, $enabledIds)) {
+                $missingDependencies[] = $this->getExtension($dependencyId);
             }
         }
 
-        if (! empty($missingDependencies)) {
+        if (!empty($missingDependencies)) {
             throw new Exception\MissingDependenciesException($extension, $missingDependencies);
         }
 
         $this->dispatcher->dispatch(new Enabling($extension));
 
-        $enabled = $this->getEnabled();
-
-        $enabled[] = $name;
+        $enabledIds[] = $name;
 
         $this->migrate($extension);
 
         $this->publishAssets($extension);
 
-        $this->setEnabled($enabled);
+        $this->setEnabled($enabledIds);
 
         $extension->enable($this->container);
 
@@ -192,17 +190,12 @@ public function disable($name)
         $dependentExtensions = [];
 
         foreach ($this->getEnabledExtensions() as $possibleDependent) {
-            foreach ($possibleDependent->extensionDependencies as $dependency) {
-                // We check all enabled extensions. For each of them, if any depend on the extension
-                // we're disabling, we add it to the list and move onto the next one.
-                if ($dependency === $extension->getId()) {
-                    $dependentExtensions[] = $possibleDependent->getId();
-                    break;
-                }
+            if (in_array($extension->getId(), $possibleDependent->getExtensionDependencies())) {
+                $dependentExtensions[] = $possibleDependent;
             }
         }
 
-        if (! empty($dependentExtensions)) {
+        if (!empty($dependentExtensions)) {
             throw new Exception\DependentExtensionsException($extension, $dependentExtensions);
         }
 
@@ -246,8 +239,8 @@ protected function publishAssets(Extension $extension)
     {
         if ($extension->hasAssets()) {
             $this->filesystem->copyDirectory(
-                $extension->getPath().'/assets',
-                $this->paths->public.'/assets/extensions/'.$extension->getId()
+                $extension->getPath() . '/assets',
+                $this->paths->public . '/assets/extensions/' . $extension->getId()
             );
         }
     }
@@ -259,7 +252,7 @@ protected function publishAssets(Extension $extension)
      */
     protected function unpublishAssets(Extension $extension)
     {
-        $this->filesystem->deleteDirectory($this->paths->public.'/assets/extensions/'.$extension->getId());
+        $this->filesystem->deleteDirectory($this->paths->public . '/assets/extensions/' . $extension->getId());
     }
 
     /**
@@ -271,7 +264,7 @@ protected function unpublishAssets(Extension $extension)
      */
     public function getAsset(Extension $extension, $path)
     {
-        return $this->paths->public.'/assets/extensions/'.$extension->getId().$path;
+        return $this->paths->public . '/assets/extensions/' . $extension->getId() . $path;
     }
 
     /**

From 8923b0cc27b0e713a1628d5bed00edc14ba5fc72 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 16:24:42 -0400
Subject: [PATCH 26/32] Rename `extensionDependencies` to
 `extensionDependencyIds` for clarity

---
 src/Extension/Extension.php        | 20 ++++++++++----------
 src/Extension/ExtensionManager.php |  4 ++--
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index bf0ba5e8d1..d9f9f1e8d1 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -89,7 +89,7 @@ protected static function nameToId($name)
      *
      * @var string[]
      */
-    protected $extensionDependencies;
+    protected $extensionDependencyIds;
 
     /**
      * Whether the extension is installed.
@@ -291,9 +291,9 @@ public function getPath()
      *
      * @return array
      */
-    public function getExtensionDependencies()
+    public function getExtensionDependencyIds()
     {
-        return $this->extensionDependencies;
+        return $this->extensionDependencyIds;
     }
 
     private function getExtenders(): array
@@ -406,13 +406,13 @@ public function migrate(Migrator $migrator, $direction = 'up')
     public function toArray()
     {
         return (array) array_merge([
-            'id'                    => $this->getId(),
-            'version'               => $this->getVersion(),
-            'path'                  => $this->getPath(),
-            'icon'                  => $this->getIcon(),
-            'hasAssets'             => $this->hasAssets(),
-            'hasMigrations'         => $this->hasMigrations(),
-            'extensionDependencies' => $this->getExtensionDependencies(),
+            'id'                     => $this->getId(),
+            'version'                => $this->getVersion(),
+            'path'                   => $this->getPath(),
+            'icon'                   => $this->getIcon(),
+            'hasAssets'              => $this->hasAssets(),
+            'hasMigrations'          => $this->hasMigrations(),
+            'extensionDependencyIds' => $this->getExtensionDependencyIds(),
         ], $this->composerJson);
     }
 }
diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index aa399531c7..56485ae613 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -147,7 +147,7 @@ public function enable($name)
 
         $missingDependencies = [];
         $enabledIds = $this->getEnabled();
-        foreach ($extension->getExtensionDependencies() as $dependencyId) {
+        foreach ($extension->getExtensionDependencyIds() as $dependencyId) {
             if (!in_array($dependencyId, $enabledIds)) {
                 $missingDependencies[] = $this->getExtension($dependencyId);
             }
@@ -190,7 +190,7 @@ public function disable($name)
         $dependentExtensions = [];
 
         foreach ($this->getEnabledExtensions() as $possibleDependent) {
-            if (in_array($extension->getId(), $possibleDependent->getExtensionDependencies())) {
+            if (in_array($extension->getId(), $possibleDependent->getExtensionDependencyIds())) {
                 $dependentExtensions[] = $possibleDependent;
             }
         }

From 12e60d9b0c94c73bae254d42db958b051cb28367 Mon Sep 17 00:00:00 2001
From: luceos <luceos@users.noreply.github.com>
Date: Fri, 2 Oct 2020 20:25:00 +0000
Subject: [PATCH 27/32] Apply fixes from StyleCI

[ci skip] [skip ci]
---
 .../DependentExtensionsException.php          |  1 -
 .../MissingDependenciesException.php          |  5 +++--
 src/Extension/ExtensionManager.php            | 22 +++++++++----------
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/Extension/Exception/DependentExtensionsException.php b/src/Extension/Exception/DependentExtensionsException.php
index 847f4e6325..b6219c3d48 100644
--- a/src/Extension/Exception/DependentExtensionsException.php
+++ b/src/Extension/Exception/DependentExtensionsException.php
@@ -12,7 +12,6 @@
 use Exception;
 use Flarum\Extension\Extension;
 
-
 /**
  * This exception is thrown when someone attempts to disable an extension
  * that other enabled extensions depend on.
diff --git a/src/Extension/Exception/MissingDependenciesException.php b/src/Extension/Exception/MissingDependenciesException.php
index ea2dbfd076..4fa1b86225 100644
--- a/src/Extension/Exception/MissingDependenciesException.php
+++ b/src/Extension/Exception/MissingDependenciesException.php
@@ -38,8 +38,9 @@ public function __construct(Extension $extension, array $missing_dependencies =
      *
      * @return array
      */
-    public function getMissingDependencyIds() {
-        return array_map(function(Extension $extension) {
+    public function getMissingDependencyIds()
+    {
+        return array_map(function (Extension $extension) {
             return $extension->getId();
         }, $this->missing_dependencies);
     }
diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index 56485ae613..7b393dc5aa 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -74,11 +74,11 @@ public function __construct(
      */
     public function getExtensions()
     {
-        if (is_null($this->extensions) && $this->filesystem->exists($this->paths->vendor . '/composer/installed.json')) {
+        if (is_null($this->extensions) && $this->filesystem->exists($this->paths->vendor.'/composer/installed.json')) {
             $extensions = new Collection();
 
             // Load all packages installed by composer.
-            $installed = json_decode($this->filesystem->get($this->paths->vendor . '/composer/installed.json'), true);
+            $installed = json_decode($this->filesystem->get($this->paths->vendor.'/composer/installed.json'), true);
 
             // Composer 2.0 changes the structure of the installed.json manifest
             $installed = $installed['packages'] ?? $installed;
@@ -96,8 +96,8 @@ public function getExtensions()
                 $installedSet[Arr::get($package, 'name')] = true;
 
                 $path = isset($package['install-path'])
-                    ? $this->paths->vendor . '/composer/' . $package['install-path']
-                    : $this->paths->vendor . '/' . Arr::get($package, 'name');
+                    ? $this->paths->vendor.'/composer/'.$package['install-path']
+                    : $this->paths->vendor.'/'.Arr::get($package, 'name');
 
                 // Instantiates an Extension object using the package path and composer.json file.
                 $extension = new Extension($path, $package);
@@ -148,12 +148,12 @@ public function enable($name)
         $missingDependencies = [];
         $enabledIds = $this->getEnabled();
         foreach ($extension->getExtensionDependencyIds() as $dependencyId) {
-            if (!in_array($dependencyId, $enabledIds)) {
+            if (! in_array($dependencyId, $enabledIds)) {
                 $missingDependencies[] = $this->getExtension($dependencyId);
             }
         }
 
-        if (!empty($missingDependencies)) {
+        if (! empty($missingDependencies)) {
             throw new Exception\MissingDependenciesException($extension, $missingDependencies);
         }
 
@@ -195,7 +195,7 @@ public function disable($name)
             }
         }
 
-        if (!empty($dependentExtensions)) {
+        if (! empty($dependentExtensions)) {
             throw new Exception\DependentExtensionsException($extension, $dependentExtensions);
         }
 
@@ -239,8 +239,8 @@ protected function publishAssets(Extension $extension)
     {
         if ($extension->hasAssets()) {
             $this->filesystem->copyDirectory(
-                $extension->getPath() . '/assets',
-                $this->paths->public . '/assets/extensions/' . $extension->getId()
+                $extension->getPath().'/assets',
+                $this->paths->public.'/assets/extensions/'.$extension->getId()
             );
         }
     }
@@ -252,7 +252,7 @@ protected function publishAssets(Extension $extension)
      */
     protected function unpublishAssets(Extension $extension)
     {
-        $this->filesystem->deleteDirectory($this->paths->public . '/assets/extensions/' . $extension->getId());
+        $this->filesystem->deleteDirectory($this->paths->public.'/assets/extensions/'.$extension->getId());
     }
 
     /**
@@ -264,7 +264,7 @@ protected function unpublishAssets(Extension $extension)
      */
     public function getAsset(Extension $extension, $path)
     {
-        return $this->paths->public . '/assets/extensions/' . $extension->getId() . $path;
+        return $this->paths->public.'/assets/extensions/'.$extension->getId().$path;
     }
 
     /**

From 4ba8aba77228b5ec9b09994683223e1cd0c37827 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 16:31:35 -0400
Subject: [PATCH 28/32] Improve extension dependency error messages, even
 though they aren't shown to users

---
 src/Extension/Exception/DependentExtensionsException.php | 2 +-
 src/Extension/Exception/MissingDependenciesException.php | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Extension/Exception/DependentExtensionsException.php b/src/Extension/Exception/DependentExtensionsException.php
index b6219c3d48..c888ddd901 100644
--- a/src/Extension/Exception/DependentExtensionsException.php
+++ b/src/Extension/Exception/DependentExtensionsException.php
@@ -30,7 +30,7 @@ public function __construct(Extension $extension, array $dependent_extensions)
         $this->extension = $extension;
         $this->dependent_extensions = $dependent_extensions;
 
-        parent::__construct(implode("\n", $dependent_extensions));
+        parent::__construct($extension->getId().' could not be disabled, because it is a dependency of: '.implode(", ", $this->getDependentExtensionIds()));
     }
 
     /**
diff --git a/src/Extension/Exception/MissingDependenciesException.php b/src/Extension/Exception/MissingDependenciesException.php
index 4fa1b86225..d5594c59c0 100644
--- a/src/Extension/Exception/MissingDependenciesException.php
+++ b/src/Extension/Exception/MissingDependenciesException.php
@@ -30,7 +30,7 @@ public function __construct(Extension $extension, array $missing_dependencies =
         $this->extension = $extension;
         $this->missing_dependencies = $missing_dependencies;
 
-        parent::__construct(implode("\n", $missing_dependencies));
+        parent::__construct($extension->getId().' could not be enabled, because it depends on: '.implode(", ", $this->getMissingDependencyIds()));
     }
 
     /**

From 294a8bca1a7f58075baf9498208f28cae57f3c2f Mon Sep 17 00:00:00 2001
From: luceos <luceos@users.noreply.github.com>
Date: Fri, 2 Oct 2020 20:31:52 +0000
Subject: [PATCH 29/32] Apply fixes from StyleCI

[ci skip] [skip ci]
---
 src/Extension/Exception/DependentExtensionsException.php | 2 +-
 src/Extension/Exception/MissingDependenciesException.php | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Extension/Exception/DependentExtensionsException.php b/src/Extension/Exception/DependentExtensionsException.php
index c888ddd901..ab26347061 100644
--- a/src/Extension/Exception/DependentExtensionsException.php
+++ b/src/Extension/Exception/DependentExtensionsException.php
@@ -30,7 +30,7 @@ public function __construct(Extension $extension, array $dependent_extensions)
         $this->extension = $extension;
         $this->dependent_extensions = $dependent_extensions;
 
-        parent::__construct($extension->getId().' could not be disabled, because it is a dependency of: '.implode(", ", $this->getDependentExtensionIds()));
+        parent::__construct($extension->getId().' could not be disabled, because it is a dependency of: '.implode(', ', $this->getDependentExtensionIds()));
     }
 
     /**
diff --git a/src/Extension/Exception/MissingDependenciesException.php b/src/Extension/Exception/MissingDependenciesException.php
index d5594c59c0..114348ca40 100644
--- a/src/Extension/Exception/MissingDependenciesException.php
+++ b/src/Extension/Exception/MissingDependenciesException.php
@@ -30,7 +30,7 @@ public function __construct(Extension $extension, array $missing_dependencies =
         $this->extension = $extension;
         $this->missing_dependencies = $missing_dependencies;
 
-        parent::__construct($extension->getId().' could not be enabled, because it depends on: '.implode(", ", $this->getMissingDependencyIds()));
+        parent::__construct($extension->getId().' could not be enabled, because it depends on: '.implode(', ', $this->getMissingDependencyIds()));
     }
 
     /**

From 36f8fa0d86156bc4b353d5cc9bb51bcc5d8f50d6 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 16:40:33 -0400
Subject: [PATCH 30/32] Fix leftover `extensionDependencies`

---
 src/Extension/Extension.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index d9f9f1e8d1..ea7b90ed04 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -206,7 +206,7 @@ public function setVersion($version)
      */
     public function calculateDependencies($extensionSet)
     {
-        $this->extensionDependencies = (new Collection(Arr::get($this->composerJson, 'require', [])))
+        $this->extensionDependencyIds = (new Collection(Arr::get($this->composerJson, 'require', [])))
             ->keys()
             ->filter(function ($key) use ($extensionSet) {
                 return array_key_exists($key, $extensionSet);

From fef0d485c69cf983e55961b289df6aeff2d2aa57 Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 17:04:45 -0400
Subject: [PATCH 31/32] Add workaround to modal bug caused by bootstrap JS

---
 js/src/admin/components/ExtensionsPage.js | 31 +++++++++++++----------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/js/src/admin/components/ExtensionsPage.js b/js/src/admin/components/ExtensionsPage.js
index 6f92f385b8..08c9615d24 100644
--- a/js/src/admin/components/ExtensionsPage.js
+++ b/js/src/admin/components/ExtensionsPage.js
@@ -116,6 +116,8 @@ export default class ExtensionsPage extends Page {
   }
 
   toggle(id) {
+    app.modal.show(LoadingModal);
+
     const enabled = this.isEnabled(id);
 
     app
@@ -129,21 +131,24 @@ export default class ExtensionsPage extends Page {
         if (!enabled) localStorage.setItem('enabledExtension', id);
         window.location.reload();
       });
-
-    app.modal.show(LoadingModal);
   }
 
   onerror(e) {
-    app.modal.close();
-
-    const error = JSON.parse(e.responseText).errors[0];
-
-    app.alerts.show(
-      { type: 'error' },
-      app.translator.trans(`core.lib.error.${error.code}_message`, {
-        extension: error.extension,
-        extensions: error.extensions.join(', '),
-      })
-    );
+    // We need to give the modal animation time to start; if we close the modal too early,
+    // it breaks the bootstrap modal library.
+    // TODO: This workaround should be removed when we move away from bootstrap JS for modals.
+    setTimeout(() => {
+      app.modal.close();
+
+      const error = JSON.parse(e.responseText).errors[0];
+
+      app.alerts.show(
+        { type: 'error' },
+        app.translator.trans(`core.lib.error.${error.code}_message`, {
+          extension: error.extension,
+          extensions: error.extensions.join(', '),
+        })
+      );
+    }, 250);
   }
 }

From d65b767e6b495052220e6d02df9c604e9e32741c Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Date: Fri, 2 Oct 2020 17:11:40 -0400
Subject: [PATCH 32/32] Remove unnecessary changes

---
 js/src/admin/components/ExtensionsPage.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/js/src/admin/components/ExtensionsPage.js b/js/src/admin/components/ExtensionsPage.js
index 08c9615d24..0ef4e9f9c4 100644
--- a/js/src/admin/components/ExtensionsPage.js
+++ b/js/src/admin/components/ExtensionsPage.js
@@ -116,8 +116,6 @@ export default class ExtensionsPage extends Page {
   }
 
   toggle(id) {
-    app.modal.show(LoadingModal);
-
     const enabled = this.isEnabled(id);
 
     app
@@ -131,6 +129,8 @@ export default class ExtensionsPage extends Page {
         if (!enabled) localStorage.setItem('enabledExtension', id);
         window.location.reload();
       });
+
+    app.modal.show(LoadingModal);
   }
 
   onerror(e) {