1607419 - option.expect(&format!(...)) runs formatting code unconditionally

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P3)

Description

[Nicolas Silva [:nical]]

And it slows some code down. The biggest offender is in BrushSegment::update_clip_task. which I caught while profiling (so surprising that I initially assumed fmt::format was showing in the profile because of some symbolication error).

The majority of the remaining expect(&format! are in recording code so we don't need to worry about performance as much. Part of me itches to get rid of them as well just to prevent this knee-self-targeting pattern to look familiar.

Comment 1

[Nicolas Silva [:nical]]

Attachment: Bug 1607419 - Avoid option.expect(&format in hot code. r=kvark

Easy to miss that the slow formatting code is run unconditionally.
The remaining instances are in recording and startup code.

Comment 2

[Aria Beingessner [:Gankra]]

fwiw there's a clippy lint for this, and nical's fix is the suggested one: https://rust-lang.github.io/rust-clippy/master/index.html#expect_fun_call

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/031a2ee21fa6
Avoid option.expect(&format in hot code. r=jrmuizel

Comment 4

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/031a2ee21fa6