Table CSS borders have changed

RESOLVED FIXED in Firefox 65



4 months ago
4 months ago


(Reporter:, Assigned: emilio)


({parity-chrome, regression, testcase})

66 Branch
Bug Flags:
in-testsuite +

Firefox Tracking Flags

(firefox-esr60 unaffected, firefox64 unaffected, firefox65+ fixed, firefox66+ fixed)



(2 attachments)



4 months ago
Posted file

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0

Steps to reproduce:

When you use a <table> with the "border" attribute with a value different than 0, even if it is on a non-HTML5 website, then the CSS border properties are not applied.

This only occurs in the current Nightly release (66). Something else has also been changed, when using the CSS border-bottom in the last <td> of the table, please see the attached files.

Actual results:

Please see the PNG in the attached zip.

Expected results:

Please see the PNG in the attached zip.

Comment 1

4 months ago
Blocks: 1509717
Has Regression Range: --- → yes
Component: Untriaged → CSS Parsing and Computation
Flags: needinfo?(emilio)
Product: Firefox → Core


4 months ago
Assignee: nobody → emilio
Ever confirmed: true
Flags: needinfo?(emilio)

Comment 2

4 months ago
Bug 1509717 removed Gecko's definition of StyleBorderStyle to use the Rust one.

The Rust version was ordered in a different way, and the table code relied on
the order in order to build the mapping for border conflict resolution.

Simplify this mapping now that border constants are ordered in terms of
priority, see the comment on top of `enum BorderStyle`.

Comment 3

4 months ago

Thank you very much for the report. Apparently our test coverage for border-collapsed tables sucks :(

Comment 4

4 months ago
Pushed by
Fix border-style conflict resolution in border-collapsed tables. r=dholbert

Comment 5

4 months ago

Comment on attachment 9036599 [details]
Bug 1520138 - Fix border-style conflict resolution in border-collapsed tables.

[Beta/Release Uplift Approval Request]

Feature/Bug causing the regression: Bug 1509717

User impact if declined: Some tables could look different.

Is this code covered by automated tests?: Yes

Has the fix been verified in Nightly?: No

Needs manual test from QE?: No

If yes, steps to reproduce:

List of other uplifts needed: None

Risk to taking this patch: Low

Why is the change risky/not risky? (and alternatives if risky): Simple fix that restores the previous behavior in a slightly simpler way.

String changes made/needed: none

Attachment #9036599 - Flags: approval-mozilla-beta?

Comment 6

4 months ago
Last Resolved: 4 months ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla66
Created web-platform-tests PR for changes under testing/web-platform/tests

Comment on attachment 9036599 [details]
Bug 1520138 - Fix border-style conflict resolution in border-collapsed tables.

[Triage Comment]
Returns us to previous behavior and adds new tests to avoid future breakage. Approved for 65.0b12.

Attachment #9036599 - Flags: approval-mozilla-beta? → approval-mozilla-beta+
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