psc-1944_add-codeowner-check-action

[harshil-roo]

JIRA: PSC-1944

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Why this PR?

We're adding a CI/CD check to automatically validate your CODEOWNERS file on every commit.

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The Problem

Invalid or misconfigured CODEOWNERS files can cause:

• Missed or incorrect code reviews
• Security gaps (anyone with write access can approve PRs)
• Slower workflows (missed team notifications)
• Audit issues (large or broken codeowner groups)

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The Solution

A new CI check will:

• Warn if your CODEOWNERS file is missing or invalid
• Check that all listed teams/users exist and have write access

For now, this is a warning only.
We’ll make it blocking soon.

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What to Do

1. Approve this PR, even if you see a warning.
2. Review your CODEOWNERS file and fix any issues. Confirm this PR is either updating an existing codeowners file or adding a new one.
3. Make sure your codeowners meet GitHub Security Standard.

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For help, ask in #support-devsecops.

[Copilot]

Pull request overview

This PR introduces automated validation of the CODEOWNERS file through a new GitHub Actions workflow. The check runs on pull requests to identify issues like missing teams, incorrect permissions, or invalid configurations—initially as a warning-only feature before becoming a blocking requirement.

• Adds a reusable GitHub Actions workflow that validates CODEOWNERS configuration on every PR
• Updates CODEOWNERS to include ownership rules for the new validation workflow itself

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
.github/workflows/codeowner-check.yml	New workflow that calls a centralized CODEOWNERS validation job from the GHAS-enablement-repo
.github/CODEOWNERS	Adds ownership entry for the new codeowner-check.yml workflow file, assigning it to @deliveroo/product-sec-eng

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[Copilot]

There's a leading whitespace before 'name' that should be removed for proper YAML formatting.

[phanimahesh]

no there isn't. stop hallucinating.

[Copilot]

The filename pattern 'codeowner-check.yml' is inconsistent with the actual filename 'codeowners-check.yml' referenced in the workflow. This pattern won't match the workflow file being added.

Suggested change

	**/codeowner-check.yml @deliveroo/product-sec-eng # DO NOT MODIFY/REMOVE, AUTOGENERATED by DevSecOps
	**/codeowners-check.yml @deliveroo/product-sec-eng # DO NOT MODIFY/REMOVE, AUTOGENERATED by DevSecOps