1568624 - serde_derive: purge deserialize_from_enums branch and deserialize_in_place feature

Status: NEW

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

Description

[Aria Beingessner [:Gankra]]

It looks like they were half removed but I still seem some references, so I'm not sure if we've actually stopped using them. Doing this may significantly improve build times!

https://searchfox.org/mozilla-central/source/.cargo/config.in#12

https://searchfox.org/mozilla-central/source/build/workspace-hack/Cargo.toml#21

context:

This special fork and special feature were hacked in to improve the performance of webrender display list deserialization. They do so by generating extra specializations of deserialize_in_place for every single instance of derive(Deserialize) which webrender would use with bincode.

Webrender has since written its own custom mini binary serialization framework, peek-poke. So no one in our codebase is actually using these specializations, but we are (possibly?) still taking the time to generate them.