1752780 - Decreasing a unitless value in the CSS panel of devtools adds `px` unit below 0

Status: VERIFIED FIXED

(DevTools :: Inspector: Rules, defect, P2)

Description

[Nicolas Hoizey]

Attachment: Screencast of the issue with a custom property

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:97.0) Gecko/20100101 Firefox/97.0

Steps to reproduce:

• open devtools
• find a CSS property with a positive value without unit (line-height for example, or a custom property)
• decrease the value down to 0 with 0.1 steps ([Option] + [↓] on macOS), and continue decreasing

Actual results:

• after going to negative values, Firefox adds a px unit

Expected results:

No unit should have been added (if the initial value was unitless), at least to properties that support unitless values like line-height) or custom properties.

It looks like it work for 1 steps, the issue is with 0.1 steps.

Comment 1

[Florens Verschelde :fvsch]

Took the liberty to triage into DevTools > Inspector: Rules.

Can confirm the issue in Nightly when using the step=-0.1 changes (Option+ArrowDown).
The step=1 step (ArrowDown) and step=10 (Shift+ArrowDown) don't seem affected.

Basic test case:

:root {
  --custom: 0.5;
  line-height: 1.4;
}

Comment 2

[Nicolas Hoizey]

Thanks Florens.

It looks like increasing the value from 0 with 0.1 steps has the same issue than decreasing.

Comment 3

[Julian Descottes [:jdescottes]]

Thanks for the report and investigation :) Confirming the issue, will be triaged later this week!

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:jdescottes, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 5

[Julian Descottes [:jdescottes]]

Attachment: Bug 1752780 - [devtools] Do not force units when incrementing unitless CSS properties

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fec9e1d961d8
[devtools] Do not force units when incrementing unitless CSS properties r=nchevobbe

Comment 7

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/fec9e1d961d8

Comment 8

[Monica Chiorean]

Reproduced the issue on build 98.0a1 without fix on Mac 10.13. Could not reproduce on Win10, only on Mac.
Verified as fixed on Mac 10.13 using build 99.0 (20220328190900).