"Update now" also applies changes

[agowa]

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

Clicking the "Update now" button while some filter list selection changes are pending also applies these changes. This is a bit unexpected as it renders the need for having two separate buttons on for "update now" and one for "apply changes" redundant.

A specific URL where the issue occurs.

chrome-extension://cjpalhdlnbpafiamejdnhcphjbkeiagm/dashboard.html#3p-filters.html

Steps to Reproduce

1. Open the uBlock Origin settings page
2. Make some changes to the filter list
3. Click "Update now" to download newest version of the filter lists.
4. Observe the changes also being applied.

Expected behavior

Either both buttons "Apply now" and "Update now" being one, or both buttons having dedicated functions.

As the "Update now" button also gets greyed out when no changes are pending I assume its function is the one that is bugged. When clicking "Update now" it should update the filter lists instead of apply changes and download missing filter lists.

When two dedicated buttons are kept the "Update now" button should:

1. Not being greyed out without pending changes.
2. Always allowing to update filter lists. Even without pending changes to the selection.
3. Not apply pending changes and keep them staged until "Apply changes" is being pressed.
4. It should always be clickable and when clicked while filter lists are considered up2date it should flush the caches and redownload them anyway (as this is most likely an attempt by the user to troubleshoot some issue and force lists to be in sync with upstream).

The "Apply changes" button on the other hand SHOULD only download the newly selected and missing filter lists, but it MAY update all outdated ones as well.

Actual behavior

"Update now" behaving exactly like "Apply changes" and also getting greyed out (unable to be clicked) when no changes are pending.

uBO version

uBlock Origin 1.67.0

Browser name and version

Brave 1.83.112 Chromium: 141.0.7390.70 (Official Build) (arm64)

Operating System and version

macOS 15.6.1 (24G90)

[u-RraaLL]

Apply changes is used to add or remove lists. When you add lists, they need to be downloaded. This triggers the automatic update. This is expected.
If you remove a list, Update now will not become available since no lists need to be updated.

The idea of Update now not showing up when you select new lists was discussed internally two years ago, but the attempt to implement this broke other stuff, so the commit was reverted. I'll just leave a link for gorhill as a reminder: https://github.com/uBlockOrigin/uBlock-discussions/discussions/781#discussioncomment-7886684
If this can now be changed without breakage, good.

The rest of your ideas basically refers to bringing purge all caches back. Not gonna happen. #2958