From f98b70d1c0bd01578c0dcdf662f5c5cddd5a7d81 Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Fri, 28 Jan 2022 11:18:40 -0500
Subject: [PATCH] Improve dealing with ambiguity in regex-based-looking network
 filters

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/1932

Reported in point 3 under "Actual behavior".
---
 src/js/static-filtering-parser.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/js/static-filtering-parser.js b/src/js/static-filtering-parser.js
index f6bb5b976..4700db4ce 100644
--- a/src/js/static-filtering-parser.js
+++ b/src/js/static-filtering-parser.js
@@ -416,6 +416,13 @@ const Parser = class {
                 len === 3 && this.slices[i+2] > 2 ||
                 len > 3 && hasBits(this.slices[i+len-3], BITSlash)
             );
+            // https://github.com/uBlockOrigin/uBlock-issues/issues/1932
+            //   Resolve ambiguity with options ending with `/` by verifying
+            //   that when a `$` is present, what follows make sense regex-wise.
+            if ( patternIsRegex && hasBits(this.allBits, BITDollar) ) {
+                patternIsRegex =
+                    this.strFromSpan(this.patternSpan).search(/[^\\]\$[^/|)]/) === -1;
+            }
         }
 
         // If the pattern is not a regex, there might be options.