codex/prs/bolinfest/study/PR-2242-study.md

DOs

• Build at least one release per OS: add one macOS and one Linux release job to catch conditional code (e.g., Landlock) and document why they exist.

# One macOS release to mirror dev behavior
- runner: macos-14
  target: aarch64-apple-darwin  # Fastest macOS runner; keeps CI quick
  profile: release

# One Linux release to catch Landlock/target-specific code
- runner: ubuntu-24.04
  target: x86_64-unknown-linux-musl
  profile: release

• Make release jobs obvious: reflect profile in the job name so release builds are easy to spot in CI.

name: ${{ matrix.runner }} - ${{ matrix.target }}${{ matrix.profile == 'release' && ' (release)' || '' }}

• Pass --profile everywhere: ensure build and test steps respect the matrix profile.

- run: find . -name Cargo.toml -mindepth 2 -maxdepth 2 -print0 \
       | xargs -0 -n1 -I{} bash -c 'cd "$(dirname "{}")" && cargo build --profile ${{ matrix.profile }}'

- run: cargo test --all-features --target ${{ matrix.target }} --profile ${{ matrix.profile }}

• Align cache keys across workflows: include profile in CI and match it in release to maximize cache hits.

# rust-ci.yml
with:
  key: cargo-${{ matrix.runner }}-${{ matrix.target }}-${{ matrix.profile }}-${{ hashFiles('**/Cargo.lock') }}

# rust-release.yml
with:
  key: cargo-release-${{ matrix.runner }}-${{ matrix.target }}-release-${{ hashFiles('**/Cargo.lock') }}

• Rebase after upstream merges: drop changes that already landed on main (e.g., imports) to keep diffs clean and avoid build breaks.

git fetch origin main
git rebase origin/main
# Resolve conflicts, ensure it builds locally, then:
git push --force-with-lease

DON’Ts

• Don’t hide release coverage: avoid sneaking a single release job into the middle of the matrix without a comment explaining why it’s there.

# Bad: release entry with no context
- runner: macos-14
  target: aarch64-apple-darwin
  profile: release  # ← unexplained

• Don’t mismatch cache keys: using different key formats between CI and release wastes caches.

# Bad: missing profile token → poor cache reuse
key: cargo-${{ matrix.runner }}-${{ matrix.target }}-${{ hashFiles('**/Cargo.lock') }}

• Don’t rely only on dev builds: release-only or target-conditional code (e.g., Landlock on Linux) can break if not built in release.

# Bad: tests/builds always run in dev profile
- run: cargo test --all-features --target ${{ matrix.target }}

• Don’t keep stale changes post-merge: if main already includes an import or refactor, remove it from your PR via rebase instead of re-adding it.

// Bad (duplicate after rebase): already in main
use codex_core::user_agent::get_codex_user_agent;