Building using xargo to support tier 3 target aarch64-apple-ios-sim error. rust-src component not found.

[MuhtasimTanmoy]

I am trying to install it through the pod.

Error is given compiling libsignal-ffi:

 Compiling libsignal-ffi v0.9.4 (/Users/tanmoy/Library/Caches/CocoaPods/Pods/External/SignalClient/94c18a0d31671033b99c08bafb98f6e4/rust/bridge/ffi)
    Finished release [optimized + debuginfo] target(s) in 2m 38s
warning: Building using xargo to support tier 3 target aarch64-apple-ios-sim.
error: `rust-src` component not found. Run `rustup component add rust-src`.
note: run with `RUST_BACKTRACE=1` for a backtrace

But I already have that required module.

Based on the toolchain used in this repository,

https://github.com/signalapp/libsignal-client/blob/master/rust-toolchain

I used the exact same rust-src

export XARGO_RUST_SRC=/Users/tanmoy/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library

This time another error building std.

 Compiling std v0.0.0 (/Users/tanmoy/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std)
error[E0557]: feature has been removed
   --> /Users/tanmoy/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/lib.rs:102:37

.....

error: aborting due to 325 previous errors; 7 warnings emitted

Some errors have detailed explanations: E0277, E0307, E0522, E0557, E0658.
For more information about an error, try `rustc --explain E0277`.
error: could not compile `core`

Update

Based on the solution provided by this repo, commenting these three solved this with keeping compatibility only to iOS devices.

CARGO_BUILD_TARGET=aarch64-apple-ios swift/build_ffi.sh --release
CARGO_BUILD_TARGET=x86_64-apple-ios swift/build_ffi.sh --release
# CARGO_BUILD_TARGET=aarch64-apple-ios-sim swift/build_ffi.sh --release --use-xargo
# CARGO_BUILD_TARGET=x86_64-apple-ios-macabi swift/build_ffi.sh --release --use-xargo
# CARGO_BUILD_TARGET=aarch64-apple-ios-macabi swift/build_ffi.sh --release --use-xargo

What the specific reason for those errors and how to get past them?

[jrose-signal]

I've never had to set XARGO_RUST_SRC, but also that doesn't look like the same toolchain at all: you're pointing at stable-x86_64-apple-darwin, and we use nightly-2021-06-08-x86_64-apple-darwin. Just to check, have you tried running rustup component add rust-src from within the libsignal-client directory?

[jrose-signal]

…ah, there is no libsignal-client directory if you are depending on this as a CocoaPod, huh. Guess we should tweak the error message: rustup +nightly-2021-06-08 component add rust-src.

You're also welcome to turn off the extra targets yourself, but we do want to build for those platforms.

[MuhtasimTanmoy]

I've never had to set XARGO_RUST_SRC, but also that doesn't look like the same toolchain at all: you're pointing at stable-x86_64-apple-darwin, and we use nightly-2021-06-08-x86_64-apple-darwin. Just to check, have you tried running rustup component add rust-src from within the libsignal-client directory?

I did use that exact toolchain specified with export (though shown only one).

Used the two specified below:

• nightly-2021-06-08-x86_64-apple-darwin
• stable-x86_64-apple-darwin

To regenerate this error simply add 'SignalClient' as a dependency in your Podfile.

pod 'SignalClient', git: 'https://github.com/signalapp/libsignal-client.git'

As per, running rustup component add rust-src from within the libsignal-client directory?, which I generated cloning this repo and using as development pod. It worked as it took the nightly rust toolchain.

 pod 'SignalClient', path: '../libsignal-client', testspecs: ["Tests"]

Solution

rustup +nightly-2021-06-08 component add rust-src

This did solve for all cases.

Could generate, release build for all these architecture finally.

• aarch64-apple-ios
• x86_64-apple-ios
• aarch64-apple-ios-sim
• x86_64-apple-ios-macabi
• aarch64-apple-ios-macabi`

Thanks for your help. Kindly tweak the error message.

Why the nightly rust build was used instead of stable, default?

[jrose-signal]

There's some discussion on why-nightly-not-stable in #141:

It builds on stable for x86, but not for aarch64, due to the use of intrinsics in the AES-GCM-SIV part. Additionally, cbindgen's support for macros requires nightly as well due to the use of unstable rustc flag --pretty=expanded. Rather than test against two different configurations, we decided to stick with nightly for now.

I'll leave this issue open to track the error message tweak.