handle noop modifier as multiple underscores

AdguardTeam · Aug 8, 2023 · 601fce7 · 601fce7
1 parent eea2cba
commit 601fce7
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Showing 3 changed files with 52 additions and 6 deletions.
diff --git a/packages/agtree/src/validator/constants.ts b/packages/agtree/src/validator/constants.ts
@@ -7,4 +7,5 @@ export const INVALID_ERROR_PREFIX = {
     NOT_NEGATABLE: 'Not negatable modifier',
     VALUE_REQUIRED: 'Value is required for the modifier',
     VALUE_FORBIDDEN: 'Value is not allowed for the modifier',
+    INVALID_NOOP: 'Invalid noop modifier',
 };
diff --git a/packages/agtree/src/validator/index.ts b/packages/agtree/src/validator/index.ts
@@ -2,6 +2,8 @@
  * @file Validator for modifiers.
  */
 
+import cloneDeep from 'clone-deep';
+
 import {
     type ModifierData,
     type ModifierDataMap,
@@ -10,6 +12,7 @@ import {
 } from '../compatibility-tables';
 import { Modifier } from '../parser/common';
 import { AdblockSyntax } from '../utils/adblockers';
+import { UNDERSCORE } from '../utils/constants';
 import { INVALID_ERROR_PREFIX } from './constants';
 
 const BLOCKER_PREFIX = {
@@ -209,6 +212,17 @@ const getBlockerDocumentationLink = (
     return specificBlockerData?.docs || null;
 };
 
+/**
+ * Validates the noop modifier (i.e. only underscores).
+ *
+ * @param value Value of the modifier.
+ *
+ * @returns True if the modifier is valid, false otherwise.
+ */
+const isValidNoopModifier = (value: string): boolean => {
+    return value.split('').every((char) => char === UNDERSCORE);
+};
+
 /**
  * Modifier validator class.
  */
@@ -259,7 +273,23 @@ class ModifierValidator {
      *
      * @returns Result of modifier validation.
      */
-    public validate = (syntax: AdblockSyntax, modifier: Modifier, isException = false): ValidationResult => {
+    public validate = (syntax: AdblockSyntax, rawModifier: Modifier, isException = false): ValidationResult => {
+        const modifier = cloneDeep(rawModifier);
+
+        // handle noop modifier which may be used as multiple underscores (not just one)
+        // https://adguard.com/kb/general/ad-filtering/create-own-filters/#noop-modifier
+        if (modifier.modifier.value.startsWith(UNDERSCORE)) {
+            // check whether the modifier value contains something else besides underscores
+            if (!isValidNoopModifier(modifier.modifier.value)) {
+                return getInvalidValidationResult(
+                    `${INVALID_ERROR_PREFIX.INVALID_NOOP}: '${modifier.modifier.value}'`,
+                );
+            }
+            // otherwise, replace the modifier value with single underscore.
+            // it is needed to check whether the modifier is supported by specific adblocker due to the syntax
+            modifier.modifier.value = UNDERSCORE;
+        }
+
         if (!this.exists(modifier)) {
             return getInvalidValidationResult(`${INVALID_ERROR_PREFIX.NOT_EXISTENT}: '${modifier.modifier.value}'`);
         }

diff --git a/packages/agtree/test/validator/index.test.ts b/packages/agtree/test/validator/index.test.ts
@@ -174,6 +174,8 @@ describe('ModifierValidator', () => {
                 'app=com.test.app',
                 '~third-party',
                 'badfilter',
+                // valid noop modifiers may be used like this:
+                '____',
             ];
             test.each(supportedModifiers)('%s', (rawModifier) => {
                 const modifier = getModifier(rawModifier);
@@ -196,7 +198,7 @@ describe('ModifierValidator', () => {
             });
         });
 
-        describe('unsupported', () => {
+        describe('invalid', () => {
             const unsupportedModifiersCases = [
                 {
                     actual: 'not-existent',
@@ -246,6 +248,10 @@ describe('ModifierValidator', () => {
                     actual: 'third-party=true',
                     expected: INVALID_ERROR_PREFIX.VALUE_FORBIDDEN,
                 },
+                {
+                    actual: '__noop__',
+                    expected: INVALID_ERROR_PREFIX.INVALID_NOOP,
+                },
             ];
             test.each(unsupportedModifiersCases)('$actual', ({ actual, expected }) => {
                 const modifier = getModifier(actual);
@@ -322,12 +328,13 @@ describe('ModifierValidator', () => {
     });
 
     describe('validate for UblockOrigin', () => {
-        describe('supported', () => {
+        describe('valid', () => {
             const supportedModifiers = [
                 'all',
                 '~third-party',
                 'badfilter',
                 'popunder',
+                '____',
             ];
             test.each(supportedModifiers)('%s', (rawModifier) => {
                 const modifier = getModifier(rawModifier);
@@ -336,7 +343,7 @@ describe('ModifierValidator', () => {
             });
         });
 
-        describe('unsupported', () => {
+        describe('invalid', () => {
             const unsupportedModifiersCases = [
                 {
                     actual: 'not-existent',
@@ -386,6 +393,10 @@ describe('ModifierValidator', () => {
                     actual: 'third-party=true',
                     expected: INVALID_ERROR_PREFIX.VALUE_FORBIDDEN,
                 },
+                {
+                    actual: '__-__',
+                    expected: INVALID_ERROR_PREFIX.INVALID_NOOP,
+                },
             ];
             test.each(unsupportedModifiersCases)('$actual', ({ actual, expected }) => {
                 const modifier = getModifier(actual);
@@ -451,7 +462,7 @@ describe('ModifierValidator', () => {
     });
 
     describe('validate for AdblockPlus', () => {
-        describe('supported', () => {
+        describe('valid', () => {
             const supportedModifiers = [
                 'domain=example.com',
                 'third-party',
@@ -465,7 +476,7 @@ describe('ModifierValidator', () => {
             });
         });
 
-        describe('unsupported', () => {
+        describe('invalid', () => {
             const unsupportedModifiersCases = [
                 {
                     actual: 'not-existent',
@@ -507,6 +518,10 @@ describe('ModifierValidator', () => {
                     actual: 'third-party=true',
                     expected: INVALID_ERROR_PREFIX.VALUE_FORBIDDEN,
                 },
+                {
+                    actual: '___',
+                    expected: INVALID_ERROR_PREFIX.NOT_SUPPORTED,
+                },
             ];
             test.each(unsupportedModifiersCases)('$actual', ({ actual, expected }) => {
                 const modifier = getModifier(actual);