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| Name | Link |
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| Latest commit | d8174d7caaa3da082e596a15a7c7131d05707373 |
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Since serde v1.0.186, this is possible without risking errors from Cargo picking incompatible versions of
serdeandserde_derive. The benefit of not enabling serde's "derive" feature is that (non-incremental) builds can become a bit faster, as serde itself (and some things depending on it) can be compiled in parallel to proc-macro2, syn, andserde_derive. See https://github.com/serde-rs/serde/issues/2584 for more discussion and background. In a project of mine where all transitive dependencies except postcard have already made the switch, this patch makes a clean build 3-4 seconds faster (out of a minute in total) on my machine.The downside of this change, besides the additional
uselines, is that it's easy to accidentally write code that breaks when used in a project where something else enables serde's "derive" feature. In scopes where the derive macros are imported fromserde_derive, importing the traits asserde::{Derive, Serialize}seems to work until it doesn't (see https://github.com/serde-rs/serde/issues/1441). I think avoided that problem in this PR, but there's no good way to test it other than occasionally editing Cargo.toml to re-enable serde's "derive" feature. I'm honestly not sure if I'd want to deal with that as a library maintainer, no hard feelings if you don't want to either.The second commit goes one step further and makes postcard's
serde_derivedependency completely optional except as a dev-dependency, since it only seems to be needed for tests and for postcard-derive-related code in schema.rs. This is less impactful since virtually every crate depending on postcard also needsserde_deriveanyway, but it shouldn't hurt either and doesn't make things any more complicated than the first commit.This is a breaking change: projects using postcard are likely to depend on serde re-exporting the derive macros, and for some of them, postcard will be the only thing enabling serde's "derive" feature. But since a 2.0 release is likely coming anyway, I wanted to pitch this change.