uninstall: call Formula#missing_dependencies directly

Library/Homebrew/cmd/uninstall.rb

@@ -76,7 +76,7 @@ def uninstall
   end
 
   def check_for_dependents(kegs)
-    return false unless result = find_some_installed_dependents(kegs)
+    return false unless result = Keg.find_some_installed_dependents(kegs)
 
     requireds, dependents = result
 
@@ -108,8 +108,16 @@ def find_some_installed_dependents(kegs)
     remaining_formulae = Formula.installed.select { |f|
       f.installed_kegs.any? { |k| Tab.for_keg(k).runtime_dependencies.nil? }
     }
-    Diagnostic.missing_deps(remaining_formulae, kegs.map(&:name)) do |dependent, required|
-      kegs_by_name = kegs.group_by(&:to_formula)
+
+    keg_names = kegs.map(&:name)
+    kegs_by_name = kegs.group_by(&:to_formula)
+    remaining_formulae.each do |dependent|
+      required = dependent.missing_dependencies(hide: keg_names)
+      required.select! do |f|
+        kegs_by_name.key?(f)
+      end
+      next unless required.any?
+
       required_kegs = required.map { |f| kegs_by_name[f].sort_by(&:version).last }
       return required_kegs, [dependent]
     end

Library/Homebrew/keg.rb

@@ -87,6 +87,41 @@ def to_s; <<-EOS.undent
     mime-info pixmaps sounds postgresql
   ].freeze
 
+  # Will return some kegs, and some dependencies, if they're present.
+  # For efficiency, we don't bother trying to get complete data.
+  def self.find_some_installed_dependents(kegs)
+    # First, check in the tabs of installed Formulae.
+    kegs.each do |keg|
+      dependents = keg.installed_dependents - kegs
+      dependents.map! { |d| "#{d.name} #{d.version}" }
+      return [keg], dependents if dependents.any?
+    end
+
+    # Some kegs won't have modern Tabs with the dependencies listed.
+    # In this case, fall back to Formula#missing_dependencies.
+
+    # Find formulae that didn't have dependencies saved in all of their kegs,
+    # so need them to be calculated now.
+    #
+    # This happens after the initial dependency check because it's sloooow.
+    remaining_formulae = Formula.installed.select { |f|
+      f.installed_kegs.any? { |k| Tab.for_keg(k).runtime_dependencies.nil? }
+    }
+
+    keg_names = kegs.map(&:name)
+    kegs_by_name = kegs.group_by(&:to_formula)
+    remaining_formulae.each do |dependent|
+      required = dependent.missing_dependencies(hide: keg_names)
+      required.select! { |f| kegs_by_name.key?(f) }
+      next unless required.any?
+
+      required_kegs = required.map { |f| kegs_by_name[f].sort_by(&:version).last }
+      return required_kegs, [dependent]
+    end
+
+    nil
+  end
+
   # if path is a file in a keg then this will return the containing Keg object
   def self.for(path)
     path = path.realpath

Library/Homebrew/test/test_uninstall.rb

@@ -31,6 +31,32 @@ def test_uninstall
     assert_empty Formulary.factory(testball).installed_kegs
   end
 
+  def test_uninstall_with_unrelated_missing_deps_in_tab
+    setup_test_formula "testball"
+    run_as_not_developer do
+      cmd("install", testball)
+      cmd("install", "testball_f2")
+      cmd("uninstall", "--ignore-dependencies", "testball_f1")
+      cmd("uninstall", testball)
+    end
+  end
+
+  def test_uninstall_with_unrelated_missing_deps_not_in_tab
+    setup_test_formula "testball"
+    run_as_not_developer do
+      cmd("install", testball)
+      cmd("install", "testball_f2")
+
+      f2_keg = f2.installed_kegs.first
+      f2_tab = Tab.for_keg(f2_keg)
+      f2_tab.runtime_dependencies = nil
+      f2_tab.write
+
+      cmd("uninstall", "--ignore-dependencies", "testball_f1")
+      cmd("uninstall", testball)
+    end
+  end
+
   def test_uninstall_leaving_dependents
     cmd("install", "testball_f2")
     run_as_not_developer do