handle invalid else directive

AdguardTeam · Oct 2, 2023 · 5b79151 · 5b79151
1 parent 31fd9bb
commit 5b79151
Showing 1 changed file with 10 additions and 2 deletions.
diff --git a/src/filters-downloader-creator.js b/src/filters-downloader-creator.js
@@ -263,6 +263,11 @@ const FiltersDownloaderCreator = (FileDownloadWrapper) => {
                         result = result.concat(resolveConditions(rulesUnderCondition, definedProperties));
                     }
                 } else {
+                    // check if there is something after !#else
+                    if (rules[elseLineIndex].trim().length !== CONDITION_ELSE_DIRECTIVE_START.length) {
+                        throw new Error(`Invalid directives: Found invalid !#else: ${rule}`);
+                    }
+
                     if (isConditionMatched) {
                         const rulesForConditionTrue = rules.slice(i + 1, elseLineIndex);
                         // Resolve inner conditions in recursion
@@ -276,9 +281,12 @@ const FiltersDownloaderCreator = (FileDownloadWrapper) => {
 
                 // Skip to the end of block
                 i = endLineIndex;
+            } else if (rule.indexOf(CONDITION_ELSE_DIRECTIVE_START) === 0) {
+                // Found !#else without !#if
+                throw new Error(`Invalid directives: Found unexpected condition else branch: ${rule}`);
             } else if (rule.indexOf(CONDITION_DIRECTIVE_END) === 0) {
-                // Found condition end without start
-                throw new Error('Invalid directives: Found unexpected condition end: ' + rule);
+                // Found !#endif without !#if
+                throw new Error(`Invalid directives: Found unexpected condition end: ${rule}`);
             } else {
                 result.push(rule);
             }