Atlantis "no projects were matched" in CI

Atlantis maps changed files to projects using when_modified (or auto-detection). If nothing in the PR matches a project, autoplan reports "no projects were matched" and runs nothing, which can look like a silent no-op.

What this error means

Atlantis comments "Ran Plan for 0 projects" or "No projects were matched" after a push, even though you expected a plan. A targeted atlantis plan -p name may say the project name was not found.

atlantis

Ran Plan for 0 projects:

No projects were matched. This can happen if the modified files do not match
any project's `when_modified` patterns.

Common causes

Changed files do not match any when_modified pattern

The PR touched files outside every project's when_modified globs, so autoplan matches nothing.

A project name or dir is wrong

A atlantis plan -p <name> or -d <dir> references a project that is not defined in atlantis.yaml.

How to fix it

Fix the when_modified globs

Confirm the changed paths against each project's when_modified list.
Add or widen a glob so the modified files map to the intended project.
Push again to trigger autoplan.

atlantis.yaml

projects:
  - name: prod
    dir: prod
    autoplan:
      when_modified: ["*.tf", "../modules/**/*.tf"]

Plan the project explicitly

Use a project name that exists in atlantis.yaml (or a valid dir) when running a targeted plan.

PR comment

atlantis plan -d prod

How to prevent it

Keep when_modified globs covering shared module paths, not just the project dir.
Name projects consistently and reference the exact name.
Verify autoplan matched the expected projects after each config change.