Error count not reset when erasing final line of My Filters

[Stevoisiak]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

If a rule on the last line of My Filters causes an error, the error will not be cleared if multiple lines of rules are erased at the same time.

A specific URL where the issue occurs.

extension://odfafepnkmbhccpbejgmiehpchacaeak/dashboard.html#1p-filters.html

Steps to Reproduce

1. Open "My Filters"
2. Fully erase all content in the rule list.
3. Enter the following as rules

   \
   \
   

4. Select all rule text and hit backspace.

2026-08-27.13-00-53.mp4

Expected behavior

Error count resets to 0.

Troubleshooting information

uBlock Origin: 1.73.0
Chromium: 151
filterset (summary):
 network: 185500
 cosmetic: 136261
 scriptlet: 48506
 html: 0
listset (total-discarded, last-updated):
 removed:
  plowe-0: null
 added:
  https://codeberg.org/just_a_husk/uBlockOrigin-AI-Blocklist/raw/branch/main/list.txt: 15760-0, 2h.48m
  https://raw.githubusercontent.com/Stevoisiak/Annoyance-Blocklist/refs/heads/main/annoyance-blocklist.txt: 179-0, 2h.48m
  https://raw.githubusercontent.com/Stevoisiak/Stevos-GenAI-Blocklist/refs/heads/main/GenAI-Blocklist-Extra.txt: 204-0, 2h.48m
  https://raw.githubusercontent.com/Stevoisiak/Stevos-GenAI-Blocklist/refs/heads/main/GenAI-Blocklist.txt: 2034-2, 2h.48m
  https://raw.githubusercontent.com/alvi-se/ai-ublock-blacklist/master/list.txt: 2696-120, 2h.48m
  fanboy-cookiemonster: 47794-122, 21h.7m
  ublock-cookies-easylist: 5827-107, 21h.7m
  fanboy-social: 17868-14, 2h.48m
  adguard-mobile-app-banners: 7920-27, 21h.7m
  easylist-newsletters: 9568-24, 21h.7m
 default:
  user-filters: 0-0, never
  ublock-filters: 53106-85, 7h.6m Δ
  ublock-badware: 10284-20, 7h.6m Δ
  ublock-privacy: 4136-3, 7h.6m Δ
  ublock-unbreak: 2803-1, 7h.6m Δ
  ublock-quick-fixes: 503-0, 7h.6m Δ
  easylist: 86520-145, 7h.6m Δ
  easyprivacy: 56444-44, 7h.6m Δ
  urlhaus-1: 47395-5, 9h.6m
filterset (user): [empty]
trustedset:
 added: [array of 7 redacted]
 removed:
  chrome-extension-scheme
userSettings:
 advancedUserEnabled: true
 userFiltersTrusted: true
hiddenSettings:
 trustedListPrefixes: ublock- https://raw.githubusercontent.com/Stevoisiak/Stevos-GenAI-Blocklist/refs/heads/main/
supportStats:
 allReadyAfter: 1387 ms (selfie)
 maxAssetCacheWait: 57 ms
 cacheBackend: indexedDB

[EshaanJaiswal]

Hi,
Can I work on this issue ?

Edit: I cloned the repo and I am able to reproduce it, fixing it and will update with a pull request

[EshaanJaiswal]

Hi @gorhill , Please Have a look

Root Cause

Off-by-one in processDeletion() in src/js/codemirror/ubo-static-filtering.js (line 967).

CodeMirror's doc.eachLine(from, to, fn) treats to as an exclusive upper bound. The current code passes to.line directly:

doc.eachLine(from.line, to.line, lineHandle => {

This skips the last line of the deletion range. When that line carries an error marker, errorCount is never decremented — and since CodeMirror then destroys the line handle internally, the stale count becomes permanent.

Fix

- doc.eachLine(from.line, to.line, lineHandle => {
+ doc.eachLine(from.line, to.line + 1, lineHandle => {

Commit with the fix: EshaanJaiswal/uBlock@2a63ff5