1890775 - Disabling property in a rule empties out the stylesheet if the rule is not on the first line of the stylesheet, and right after another rule declaration (without whitespace)

Status: VERIFIED FIXED

(DevTools :: Inspector: Rules, defect, P1)

Description

[Nicolas Chevobbe [:nchevobbe]]

Steps to reproduce

1. Navigate to data:text/html,<meta charset=utf8><style>%0Ahtml{}body{color:red;background:gold;}</style>Hello
2. Open the inspector and select the body node
3. In the body rule, unselect the color property

Expected results

The Hello text gets black, the background color stays gold

Actual results

The Hello text gets black, the background color gets white, and if you navigate to the style editor, you can see that the stylesheet is empty

---

The stylesheet has the following content:

html{}body{color:red;background:gold;}

When InspectorUtils.replaceBlockRuleBodyTextInStylesheet is called to replace the content of the second rule, get_byte_index_from_line_and_column (glue.rs) returns an erroneous index as it doesn't account for the line break character.
This means that Servo_ReplaceBlockRuleBodyTextInStylesheetText (glue.rs) includes the closing curly bracket of the previous rule when building the string it should parse (i.e. }body{color:red;background:gold;}).
This is a parsing error as the parser didn't encountered any opening bracket before, and the function will return null.

So we should fix the index computation, but also maybe avoid emptying the stylesheet when the function returns null.

Comment 1

[Nicolas Chevobbe [:nchevobbe]]

Attachment: Bug 1890775 - [devtools] Fix get_byte_index_from_line_and_column line index computation. r=#layout,#devtools-reviewers.

We were getting a line byte index for the
actual char matching the line we want, but
we actually need the index after that
new line char.
A test case is added to cover this fix.

Comment 2

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 1882964

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/215c06cd23e0
[devtools] Fix get_byte_index_from_line_and_column line index computation. r=layout-reviewers,devtools-reviewers,emilio.

Comment 4

[Cristina Horotan [:chorotan]]

https://hg.mozilla.org/mozilla-central/rev/215c06cd23e0

Comment 5

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Reproducible on a 2024-04-10 Nightly build on Windows 10.
Verified as fixed on Firefox Nightly 127.0a1 and Firefox 126.0b7 on Windows 10, Ubuntu 22, macOS 12.