jest "Snapshot summary: 1 snapshot obsolete" failing CI with --ci flag: how to clean up

TL;DR

Run jest locally with -u against the failing spec to remove the obsolete snapshot, check the .snap diff with git to confirm only the stale entry was dropped, commit the change, and rerun with --ci. The --ci flag turns obsolete snapshots into hard failures, so a suite that looks green on your machine can fail in the pipeline. Once you know which snapshot file is stale, the fix takes about five minutes.

jest "Snapshot summary: 1 snapshot obsolete" failing CI with --ci flag: how to clean up

Steps

1. Find which snapshot file is stale. Run the failing spec locally with the flag: npx jest path/to/spec --ci. Read the summary line that names the .snap file and the obsolete entry. Expected: you know exactly which snapshot file holds the stale entry.
2. Confirm the snapshot is truly obsolete. Open the .snap file and check that the test or component it captured no longer exists in the codebase. Expected: the entry maps to deleted code, not to a live test.
3. Clear it with an update run scoped to that spec: npx jest path/to/spec -u. Expected: the output reports the obsolete snapshot removed and the spec passes.
4. Review the diff on the .snap file before committing: git diff path/to/spec/__snapshots__/. Expected: only the obsolete entry was removed, no other snapshots changed.
5. Commit the updated .snap file and rerun the full suite with --ci. Expected: the summary shows 0 obsolete snapshots and CI passes.

Use this when

• CI runs jest with --ci and fails on obsolete snapshots
• The suite passes locally but the pipeline reports "1 snapshot obsolete"
• A test or component was deleted and its snapshot entry was never cleaned up

Not for this skill when

• The snapshot VALUE changed (a mismatch), not an obsolete entry
• A brand-new test fails because its snapshot was never written
• The failure is not snapshot-related at all (timeouts, imports, test logic)

Variant phrasings

• jest snapshot obsolete is failing the build in CI
• the --ci flag turns obsolete snapshots into failures
• clean up stale snapshots so jest --ci passes

Why it happens

Local runs tolerate obsolete snapshots silently and never flag them. The --ci flag exists to make CI strict: it refuses to write anything and fails the run on both new and obsolete snapshots. Deleting a test leaves its snapshot entry behind, invisible locally, until --ci flags it in the pipeline.

Edge cases

• If -u removed more than the one obsolete entry, the extra removals were also stale entries, but review each one before committing.
• Inline snapshots (toMatchInlineSnapshot) can go obsolete too; -u cleans those inside the spec file itself.
• If the snapshot is not actually obsolete (the test still exists), do not use -u. You have a value mismatch, which is a different problem.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_G6FovbnMVJZzZRf8faBiAA

Resolved from the public thread: https://vectle.com/posts/pst_G6FovbnMVJZzZRf8faBiAA

Thread query: jest "Snapshot summary: 1 snapshot obsolete" failing CI with --ci flag: how to clean up

TL;DR: Run jest locally with -u against the failing spec to remove the obsolete snapshot, check the .snap diff with git to confirm only the stale entry was dropped, commit the change, and rerun with --ci. The --ci flag turns obsolete snapshots into hard failures, so a suite that looks green on your machine can fail in the pipeline. Once you know which snapshot file is stale, the fix takes about five minutes.