1514464 - Clamp selection color value between 0 and 255 in nsLookAndFeel.mm

Status: RESOLVED FIXED

(Core :: Widget: Cocoa, defect)

Description

[Tim Nguyen :ntim]

(In reply to Markus Stange [:mstange] from bug 1513401 comment #12)
> > +    value = 255 - (255 - value) * factor;
> 
> I realized a problem in the math: if value is less that 128, this will be
> 255 - [something larger than 255], which will be negative and then
> wraparound into a large uint16_t value when assigned to "value". So I think
> the "(255 - value) * factor" part should be wrapped in a
> mozilla::clamped(..., 0, 255).
> 
> This is not that urgent to fix because macOS does not, as far as I know,
> have gray highlighting colors that are darker than 128. But it should still
> be fixed.

Comment 1

[Tim Nguyen :ntim]

Attachment: Bug 1514464 - Clamp selection color value between 0 and 255 in nsLookAndFeel.mm. r=mstange

Comment 2

[Ryan VanderMeulen [:RyanVM]]

Might as well take this on Beta as well since bug 1514464 is being uplifted there.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/655c49c71be0
Clamp selection color value between 0 and 255 in nsLookAndFeel.mm. r=mstange

Comment 4

[Tim Nguyen :ntim]

Comment on attachment 9031670 [details]
Bug 1514464 - Clamp selection color value between 0 and 255 in nsLookAndFeel.mm. r=mstange

[Beta/Release Uplift Approval Request]

Feature/Bug causing the regression: Bug 1513401

User impact if declined: None, just makes the code more sane in case the OS changes the provided selection color

Is this code covered by automated tests?: No

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): low risk, one line cocoa change

String changes made/needed:

Comment 5

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/655c49c71be0

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9031670 [details]
Bug 1514464 - Clamp selection color value between 0 and 255 in nsLookAndFeel.mm. r=mstange

[Triage Comment]
Adds a bit of sanity checking to the selection color code in case the OS gives bogus values. Approved for 65.0b5.

Comment 7

[Eliza Balazs [:ebalazs_]]

https://hg.mozilla.org/releases/mozilla-beta/rev/04d44d6052d1