Git "Your local changes would be overwritten" in CI

Git stopped a checkout, pull, or merge because the working tree has uncommitted changes that the operation would clobber. On a reused or self-hosted runner this means the previous job left modified or generated files behind.

What this error means

A checkout/pull step fails with error: Your local changes to the following files would be overwritten by checkout and Please commit your changes or stash them before you switch branches. It surfaces on persistent runners that reuse the workspace, not on ephemeral ones.

git checkout output

error: Your local changes to the following files would be overwritten by checkout:
	package-lock.json
Please commit your changes or stash them before you switch branches.
Aborting

Common causes

A dirty workspace from a previous job

A reused runner kept build artifacts or generated files (a regenerated lockfile, compiled output) as uncommitted changes, so the next checkout would overwrite them and Git refuses.

Tracked files modified by a build step

A step edited a tracked file in place (formatting, codegen) before a later checkout/pull, leaving the tree dirty.

How to fix it

Reset the workspace before checkout

Discard uncommitted changes and untracked files so the checkout has a clean tree to land in.

Terminal

git reset --hard
git clean -ffdx
git checkout main

Force a clean checkout in the workflow

On GitHub Actions, actions/checkout cleans the workspace by default; ensure it is not disabled.

.github/workflows/ci.yml

- uses: actions/checkout@v4
  with:
    clean: true   # default; resets the workspace each run

How to prevent it

Use ephemeral runners, or hard-reset + clean at job start on persistent ones.
Avoid committing generated files that build steps rewrite.
Keep actions/checkout clean step enabled (the default).