First mentioned in T239725#5709390. Here is a minimal example that creates broken numbers in Firefox:
* <ref>x</ref> <references />
Firefox renders a "2." down in the <references> section. Chrome renders a "1.", as expected.
This means the CSS counters we are using are somehow messing with the build-in numbering of the numbered list in Firefox. This should not happen.
| Subject | Repo | Branch | Lines +/- | |
|---|---|---|---|---|
| Fix possibly broken reference list counters in Firefox | mediawiki/extensions/Cite | master | +7 -5 |
I did a bisect and the bug was not there before the patch https://gerrit.wikimedia.org/r/553111. That was the patch that introduced new CSS counters for sub-references.
The minimal example is not even using extended references. The only line of code that is active in this example is a counter-reset on the <ol> the <references> list is made of. It appears like Firefox does have a bug where any counter-reset on an <ol> somehow messes with the build-in counter, and makes it continue from the previous, unrelated list.
According to https://drafts.csswg.org/css-lists-3/#list-item-counter the build-in counter does have a name: list-item. According to https://bugzilla.mozilla.org/show_bug.cgi?id=1545746#c5 we are supposed to reset both the custom and the build-in list-item counter whenever using counter-reset on an <ol> element. I did just that now, and it seems to work. However, it doesn't explain why it was behaving different in Chrome.
Change 554484 had a related patch set uploaded (by Thiemo Kreuz (WMDE); owner: Thiemo Kreuz (WMDE)):
[mediawiki/extensions/Cite@master] Fix possibly broken reference list counters in Firefox
Change 554484 merged by jenkins-bot:
[mediawiki/extensions/Cite@master] Fix possibly broken reference list counters in Firefox