## Why
`argument-comment-lint` had become a PR bottleneck because the repo-wide
lane was still effectively running a `cargo dylint`-style flow across
the workspace instead of reusing Bazel's Rust dependency graph. That
kept the lint enforced, but it threw away the main benefit of moving
this job under Bazel in the first place: metadata reuse and cacheable
per-target analysis in the same shape as Clippy.
This change moves the repo-wide lint onto a native Bazel Rust aspect so
Linux and macOS can lint `codex-rs` without rebuilding the world
crate-by-crate through the wrapper path.
## What Changed
- add a nightly Rust toolchain with `rustc-dev` for Bazel and a
dedicated crate-universe repo for `tools/argument-comment-lint`
- add `tools/argument-comment-lint/driver.rs` and
`tools/argument-comment-lint/lint_aspect.bzl` so Bazel can run the lint
as a custom `rustc_driver`
- switch repo-wide `just argument-comment-lint` and the Linux/macOS
`rust-ci` lanes to `bazel build --config=argument-comment-lint
//codex-rs/...`
- keep the Python/DotSlash wrappers as the package-scoped fallback path
and as the current Windows CI path
- gate the Dylint entrypoint behind a `bazel_native` feature so the
Bazel-native library avoids the `dylint_*` packaging stack
- update the aspect runtime environment so the driver can locate
`rustc_driver` correctly under remote execution
- keep the dedicated `tools/argument-comment-lint` package tests and
wrapper unit tests in CI so the source and packaged entrypoints remain
covered
## Verification
- `python3 -m unittest discover -s tools/argument-comment-lint -p
'test_*.py'`
- `cargo test` in `tools/argument-comment-lint`
- `bazel build
//tools/argument-comment-lint:argument-comment-lint-driver
--@rules_rust//rust/toolchain/channel=nightly`
- `bazel build --config=argument-comment-lint
//codex-rs/utils/path-utils:all`
- `bazel build --config=argument-comment-lint
//codex-rs/rollout:rollout`
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/16106).
* #16120
* __->__ #16106
## Why
The `argument-comment-lint` entrypoints had grown into two shell
wrappers with duplicated parsing, environment setup, and Cargo
forwarding logic. The recent `--` separator regression was a good
example of the problem: the behavior was subtle, easy to break, and hard
to verify.
This change rewrites those wrappers in Python so the control flow is
easier to follow, the shared behavior lives in one place, and the tricky
argument/defaulting paths have direct test coverage.
## What changed
- replaced `tools/argument-comment-lint/run.sh` and
`tools/argument-comment-lint/run-prebuilt-linter.sh` with Python
entrypoints: `run.py` and `run-prebuilt-linter.py`
- moved shared wrapper behavior into
`tools/argument-comment-lint/wrapper_common.py`, including:
- splitting lint args from forwarded Cargo args after `--`
- defaulting repo runs to `--manifest-path codex-rs/Cargo.toml
--workspace --no-deps`
- defaulting non-`--fix` runs to `--all-targets` unless the caller
explicitly narrows the target set
- setting repo defaults for `DYLINT_RUSTFLAGS` and `CARGO_INCREMENTAL`
- kept the prebuilt wrapper thin: it still just resolves the packaged
DotSlash entrypoint, keeps `rustup` shims first on `PATH`, infers
`RUSTUP_HOME` when needed, and then launches the packaged `cargo-dylint`
path
- updated `justfile`, `rust-ci.yml`, and
`tools/argument-comment-lint/README.md` to use the Python entrypoints
- updated `rust-ci` so the package job runs Python syntax checks plus
the new wrapper unit tests, and the OS-specific lint jobs invoke the
wrappers through an explicit Python interpreter
This is a follow-up to #16054: it keeps the current lint semantics while
making the wrapper logic maintainable enough to iterate on safely.
## Validation
- `python3 -m py_compile tools/argument-comment-lint/wrapper_common.py
tools/argument-comment-lint/run.py
tools/argument-comment-lint/run-prebuilt-linter.py
tools/argument-comment-lint/test_wrapper_common.py`
- `python3 -m unittest discover -s tools/argument-comment-lint -p
'test_*.py'`
- `python3 ./tools/argument-comment-lint/run-prebuilt-linter.py -p
codex-terminal-detection -- --lib`
- `python3 ./tools/argument-comment-lint/run.py -p
codex-terminal-detection -- --lib`
