fix(rust): handle rustup check exit code 100 as non-error

[shalk]

Summary

Fixes the issue where mise outdated fails when rust toolchain updates are
available.

Problem

rustup check returns exit code 100 when toolchain updates are available, which
is normal behavior and not an error. Previously, mise treated this as a failure,
causing mise outdated to report:

Error getting outdated info for core:rust@stable: command ["rustup", "check"]
exited with code 100

Solution

Changed the outdated_info method in src/plugins/core/rust.rs to use
.unchecked().run() instead of .read(), allowing mise to manually handle the
exit code and parse the output correctly even when rustup returns 100.

Testing

• Built successfully with cargo build --release
• Verified with cargo check
  EOF

[gemini-code-assist]

Code Review

This pull request modifies the Rust plugin to correctly handle exit code 100 from 'rustup check', which signifies available updates rather than a failure. A review comment suggests refining the error handling because the current use of '.unchecked()' suppresses all non-zero exit codes, potentially hiding genuine errors. It is recommended to explicitly verify that the exit code is either 0 or 100.

[greptile-apps]

Greptile Summary

This PR fixes mise outdated incorrectly failing for Rust toolchains by treating rustup check's exit code 100 — which simply means an update is available — as a non-error. The previous code used .read(), which propagated every non-zero exit as a hard failure. The new code uses .unchecked().run() with manual exit-code inspection: codes 0 and 100 are both treated as success, while any other code bails with a descriptive error that includes both the exit code and the captured stderr output.

Key changes:

• Replaced .read() with .stdout_capture().stderr_capture().unchecked().run() in outdated_info
• Added explicit guard: only exit codes 0 and 100 are accepted; all other codes surface a proper error with the captured stderr message
• The previous reviewer concern about silently swallowing all non-zero exit codes has been addressed in this revision

Confidence Score: 5/5

Safe to merge — the fix is minimal, correct, and the prior concern about swallowed error codes has been resolved.

The change correctly restricts the non-error treatment to exactly exit codes 0 and 100, bailing with a clear diagnostic for anything else. The previous reviewer concern about silently swallowing all non-zero exit codes was already addressed in this revision. No regressions are apparent and the logic is straightforward.

No files require special attention.

Important Files Changed

Filename	Overview
src/plugins/core/rust.rs	Refactors outdated_info to use .unchecked().run() with explicit exit code handling so that rustup's exit code 100 (update available) is no longer treated as an error, while all other unexpected codes still propagate correctly.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[outdated_info called] --> B{Is version a semver?}
    B -- Yes --> C[OutdatedInfo::resolve via registry]
    B -- No --> D[Run rustup check unchecked]
    D --> E{Exit code?}
    E -- 0 --> F[Parse stdout for update lines]
    E -- 100 --> F
    E -- other --> G[bail with exit code and stderr]
    F --> H{Line matches target triple and version regex?}
    H -- Yes --> I[Return Some OutdatedInfo]
    H -- No --> J[Return None]

Loading

_{Reviews (4): Last reviewed commit: "fix(backend): include rustup check stder..." | Re-trigger Greptile}

[jdx]

I think greptile is right that we should include stderr in the error message