Too high RAM usage in tests

[mo8it]

After running cargo t --workspace, all of my RAM is used and my OOM starts killing processes. I have 16 GB of RAM. The tests that cause that are those of helix-tui. I tried using the -j 1 option, but it didn't help.
I can skip the tests of helix-tui for now. But are you planning to address this issue? A unit test shouldn't require 16 GB of RAM.

[mo8it]

After running cargo t --workspace --exclude helix-tui, the unit tests run to completion, but my RAM was at about 95% until the end. It might be worth reducing the memory usage of all tests if possible.

[kirawi]

I can't replicate. The highest it ever went was 1gb. What system & OS are you running, what is your system environment, and do you have a custom config for Rust?

[mo8it]

Hardware Information:

• Memory: 16,0 GiB
• Processor: AMD Ryzen™ 7 5800H with Radeon™ Graphics × 16
• Graphics: AMD Radeon™ Graphics

Software Information:

• OS Name: Fedora Linux 39.20240223.0 (Silverblue)
• OS Type: 64-bit
• GNOME Version: 45.4
• Windowing System: Wayland
• Kernel Version: Linux 6.7.5-200.fc39.x86_64

---

Content of ~/.cargo/config.toml:

[target.x86_64-unknown-linux-gnu]
linker = "clang"
rustflags = [
  "-C",
  "link-arg=-fuse-ld=/usr/bin/mold",
  "-C",
  "target-cpu=native",
]

[profile.release]
lto = true
codegen-units = 1

[pakhrom]

I too have 100% RAM usage by helix tests on Arch at which point it gets OOM killed.

[pakhrom]

Sorry for necrobumping an old discussion. In my previous comment I didn't provide sufficient information for replicating the issue. I will try to investigate this issue further and create a new issue if I manage to find the cause of it.

[pakhrom]

The issue are the rustdoc tests in helix-tui. Running helix-tui tests skipping doc tests (cargo test -p helix-tui --lib) takes up not nearly as much RAM as running them with doc tests. I believe this has nothing to do with the helix project and is an issue with the current version of rustdoc (therefore, Rust) that's being used in the project. I ran the tests using the latest stable Rust version 1.94.1 and don't see RAM usage as high as with the current version 1.87.0. I don't really know If I should open a new issue for this, bumping the Rust version seems dangerous for me. I'm still very new to Rust development, so correct me if I'm wrong.

[Abdillah]

Changing Rust version through rust-toolchain.toml make the build possible, right? So I don't think you should report this as bug for Helix.

Maybe try to isolate which rustdoc test causing that much memory usage. If you have any information regarding report of this bug in rust side, you may share the info here. Other than that, the best action is just to wait.

[pakhrom]

The build is possible with the current Rust version, it's just the helix-tui tests that take up all of my RAM. It isn't really an issue, because tests successfully complete in CI and you don't really need to run doc tests locally. The issue is that Helix currently uses an old version of Rust (which is reasonable, nothing wrong here) and the version of rustdoc in this version was probably just unoptimized, because in the newer version it didn't take up all my RAM trying to run the doc tests, so everything's fine.

Also, I didn't change rust-toolchain.toml, I just changed the Rust binaries used for the project using cargo switch.