Cargo APK 0.9.3 and later does not appear to respect `rustflags` in `config.toml`

[Hoodad]

Hello!

It appears that when building using cargo-apk 0.9.3 and later the RUSTFLAGS set in /.cargo/config.toml are not being included. In our code-base we depend on the flag rust flag "--cfg tokio_unstable" being set. However when building this flag is not being set. Earlier version of cargo-apk like 0.9.2 does not show this behavior.

Quickly skimming the diff there appears to have been some changes to how flags are being handled, though I haven't looked to close yet.

[MarijnS95]

Your colleague already addressed that in rust-mobile/ndk#357, but I have yet to make a release pending reviews on my other cargo-apk related PRs.

[Hoodad]

Oh 😅! Thanks, closing this issue then!

[MarijnS95]

Fwiw the breakage in cargo-apk 0.9.2 => 0.9.3 came paired with ndk-build 0.6.0 => 0.7.0, where rust-mobile/ndk#298 landed.

[MarijnS95]

@Hoodad @Jake-Shadle you may also be interested in rust-mobile/ndk#260 / rust-mobile/ndk#365 regarding your internal usage of cargo-apk and other android-ndk-rs crates; community feedback from actual users on moving forward is invaluable, let me know how you feel about this situation!

[Hoodad]

Thanks for the heads up and sorry for being a bit vacant and not replying to your question @MarijnS95 There will be some additional speed on Android side now going forward. We're currently inventorying what we need going forward and looking at what options are available.

Regarding the reason why I created the issue in the first place. I have tested latest version of cargo-apk and it still fails to respect the rust flags. I created a minimal example reproducing the issue here https://github.com/Hoodad/cargo-apk-rust-flags-repro

Even if cargo-apk will become (or maybe already is) deprecated I wanted to feedback that the issue still persist.

[MarijnS95]

So the issue is simply that all these ways of setting rustflags are mutually exclusive. Meaning that because cargo-apk (and IIRC also xbuild) set CARGO_ENCODED_RUSTFLAGS we are suddenly responsible for scanning for all the four sources of rustflags with the given precedence ordering and append them to CARGO_ENCODED_RUSTFLAGS. We currently only do this for RUSTFLAGS and CARGO_ENCODED_RUSTFLAGS, but would have to expand to target.<triple>.rustflags + target.<cfg>.rustflags and build.rustflags shown here.