mediasoup-sys Build Error: "Subproject exists but has no meson.build file"

[mattmillen888]

Bug Report

Operating system: macOS 14.3 (Darwin 24.3.0)
Node version: N/A (Using Rust implementation)
npm version: N/A (Using Rust implementation)
gcc/clang version: Apple clang version 16.0.0 (clang-1600.0.26.6)
mediasoup version: 0.17.1 (Rust crate)
mediasoup-client version: N/A (Using Rust implementation)

Issue description

When building a Rust project that depends on the mediasoup crate (v0.17.1), the build fails with the following error:

meson.build:227:19: ERROR: Subproject exists but has no meson.build file.

This occurs during the compilation of the mediasoup-sys v0.9.1 dependency. The issue is that the flatbuffers subproject is missing its meson.build file, which should have been added by a patch from wrapdb.mesonbuild.com.
The build process downloads the flatbuffers source code correctly, but fails to apply the patch that would add the necessary meson.build file.
I was able to fix this issue by manually downloading and applying the patch:

1. Navigate to the mediasoup-sys directory in the Cargo registry:

cd ~/.cargo/registry/src/index.crates.io-*/mediasoup-sys-0.9.1/subprojects

2. Download the patch:

curl -L https://wrapdb.mesonbuild.com/v2/flatbuffers_24.3.6-1/get_patch -o flatbuffers_patch.zip

3. Extract and apply the patch:

unzip -o flatbuffers_patch.zip -d flatbuffers-24.3.6
mv flatbuffers-24.3.6/flatbuffers-24.3.6/meson.build flatbuffers-24.3.6/
mv flatbuffers-24.3.6/flatbuffers-24.3.6/LICENSE.build flatbuffers-24.3.6/
rmdir flatbuffers-24.3.6/flatbuffers-24.3.6

After applying these steps, the build succeeds. This suggests that there might be an issue with how the mediasoup-sys crate handles the flatbuffers.wrap file or how the Meson build system applies patches from wrapdb.
This issue affects anyone trying to use the Rust implementation of mediasoup on macOS, and possibly other platforms as well.

[ibc]

Please run "invoke (or make) clean-all" in worker/ folder and try again.

Note: I am closing the ticket because I am pretty sure it's that.

[ibc]

Ok reopening because I maybe wrong. @nazar-pc any thoughts?

[nazar-pc]

Does it build if you clone the repo? It clearly compiles fine in CI, so I'm wondering what it could be.

[bekriebel]

When this happens, I typically run cargo clean on the project and if that doesn't work, I blow away my cargo registry cache rm -r ~/.cargo/registry/. You can also find the specific folder mediasoup-sys is in, but it's faster to just rm the whole path. That tends to fix it for me.

It seems to happen when multiple things try to compile mediasoup-sys at the same time (like if I have two projects open in vscode that both depend on mediasoup, and rust-analyzer does a build on both of them). This is actually one of my main drivers for opening #1498; to reduce the places where that build is occurring in my workspace.

[nazar-pc]

Interesting, I guess we can try to add a lock to make sure two things are not competing with each other. Though the whole thing sounds like Meson issue. I don't like that it writes stuff into subprojects directory instead of build target directory, which messes up ~/.cargo/registry (which should never be written to by the build scripts).

Another alternative would be to copy stuff from there to build output before running Meson, but that feels wrong too.

[ibc]

Can we close this ticket? Is there something actionable from our side? I don't want to keep this ticket open forever without real activity or real work on it.

[nazar-pc]

I guess it'd be nice if upstream modified Meson behavior, we could then take advantage of it here.

Until then we could still work around it if there is enough demand with additional checks in the code, though so far it was not happening very often.

[wxj127]

I seem to be having the same problem using the rust package
operating system:windows
Development Language: rust
Version: 0.19.0
Found ninja.exe-1.10.2.git.kitware.jobserver-1 at D:/programCode/rust/webrtc/webrtc/target/debug/build/mediasoup-sys-a182db445651bb97/out/out/pip_meson_ninja/bin/ninja.exe

Visual Studio environment is needed to run Ninja. It is recommended to use Meson wrapper:
D:\programCode\rust\webrtc\webrtc\target\debug\build\mediasoup-sys-a182db445651bb97\out\out\pip_meson_ninja\bin\meson compile -C D:\programCode\rust\webrtc\webrtc\target\debug\build\mediasoup-sys-a182db445651bb97\out\build

ERROR: Unhandled python OSError. This is probably not a Meson bug, but an issue with your build environment.

D:\programCode\rust\webrtc\webrtc> D:\programCode\rust\webrtc\webrtc\target\debug\build\mediasoup-sys-a182db445651bb97\out\out\pip_meson_ninja\bin\meson compile -C D:\programCode\rust\webrtc\webrtc\target\debug\build\mediasoup-sys-a182db445651bb97\out\build

ERROR: Current directory is not a meson build directory: D:\programCode\rust\webrtc\webrtc\target\debug\build\mediasoup-sys-a182db445651bb97\out\build.
Please specify a valid build dir or change the working directory to it.
It is also possible that the build directory was generated with an old
meson version. Please regenerate it in this case.

[nazar-pc]

You can try deleting D:\programCode\rust\webrtc\webrtc\target\debug\build\mediasoup-sys-a182db445651bb97\out and see if it helps.

What did you do before you got that error? That is the most important question. If we can reproduce it reliably, we'll be able to verify the fix.

[wxj127]

You can try deleting D:\programCode\rust\webrtc\webrtc\target\debug\build\mediasoup-sys-a182db445651bb97\out and see if it helps.

What did you do before you got that error? That is the most important question. If we can reproduce it reliably, we'll be able to verify the fix.

I also tried cargo clean and then build and the same problem still occurred. I also tried deleting the target directory.

[ibc]

What did you do before you got that error? That is the most important question. If we can reproduce it reliably, we'll be able to verify the fix.

@wxj127 can you answer this question please?