Running Compatibility Checks

Use the repository's compatibility runner to compare the current checkout with a base revision. The runner mirrors the CI package selection (core and acme), builds both verifiers in release mode, and preserves the generated reports.

Run the comparison

From the repository root:

just compatibility

The default base is the local origin/main ref. When the comparison must use the latest remote main, fetch it first:

git fetch origin main
just compatibility

Pass another commit, branch, or tag when requested:

just compatibility <base-ref>

Do not require a clean worktree. The candidate is the current checkout, including uncommitted source changes. The base runs in a temporary detached worktree, so the command does not switch or modify the active checkout. The candidate build and prepared corpus are written under target/.

Interpret the result

The runner prints the Markdown summary and the report directory. Inspect at least:

• summary.md for introduced and fixed diagnostics
• comparison.json for the structured comparison
• base.log and candidate.log when either verifier fails
• comparison.log when report comparison fails

Exit statuses have stable meanings:

• 0: no compatibility regressions
• 1: the candidate introduces compatibility errors; the reports are valid and must be reviewed
• 2: preparation, verification, or comparison could not execute correctly

Do not describe status 1 as a broken checker. Report the introduced errors from summary.md. For status 2, diagnose the relevant log and distinguish network/package-corpus failures from compiler failures.

Run one revision without comparison

Only use a direct verification when the user explicitly wants one revision rather than a base/candidate regression check:

cargo run --release -p tests-compatibility -- prepare --preset core --preset acme
cargo run --release -p tests-compatibility -- verify --preset core --preset acme

The direct verifier also uses status 1 for a valid report containing errors and status 2 for an execution failure.