Validate existing contributor

.github/scripts/python/validate-existing-contributors/Pipfile

@@ -0,0 +1,16 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+
+[dev-packages]
+black = "==23.1.0"
+pytest = "==7.2.1"
+mypy = "==1.6.1"
+pylint = "==3.0.2"
+types-requests = "==2.31.0.10"
+
+[requires]
+python_version = "3.11"

.github/scripts/python/validate-existing-contributors/__main__.py

@@ -0,0 +1,90 @@
+"""
+© Ocado Group
+Created on 08/01/2024 at 09:47:25(+00:00).
+
+Validate all contributors have signed the contribution agreement.
+"""
+
+import json
+import os
+import typing as t
+from email.utils import parseaddr
+
+PullRequest = t.Dict[str, t.Any]
+Contributors = t.Set[str]
+
+# pylint: disable-next=line-too-long
+CONTRIBUTING_FILE_NAME = "CONTRIBUTING.md"
+CONTRIBUTORS_HEADER = "### 👨\u200d💻 Contributors 👩\u200d💻"
+
+
+def get_inputs():
+    """Get script's inputs.
+
+    Returns:
+        A JSON object of the pull request.
+    """
+
+    pull_request: PullRequest = json.loads(os.environ["PULL_REQUEST"])
+
+    return pull_request
+
+
+def get_signed_contributors() -> Contributors:
+    """Get the contributors that have signed the contribution agreement.
+
+    Returns:
+        A set of the contributors' email addresses.
+    """
+
+    with open(
+        f"../../../../{CONTRIBUTING_FILE_NAME}",
+        "r",
+        encoding="utf-8",
+    ) as contributing:
+        lines = contributing.read().splitlines()
+
+    # NOTE: +2 because we don't want the header and its proceeding blank line.
+    lines = lines[lines.index(CONTRIBUTORS_HEADER) + 2 :]
+
+    return {parseaddr(line)[1] for line in lines}
+
+
+def assert_contributors(
+    pull_request: PullRequest,
+    signed_contributors: Contributors,
+):
+    """Assert that all contributors have signed the contribution agreement.
+
+    Args:
+        pull_request: The JSON object of the pull request.
+        signed_contributors: The contributors that have signed the contribution
+            agreement.
+    """
+
+    contributors: Contributors = {
+        author["email"]
+        for commit in pull_request["commits"]
+        for author in commit["authors"]
+    }
+
+    unsigned_contributors = contributors.difference(signed_contributors)
+
+    assert not unsigned_contributors, (
+        "The following contributors have not signed the agreement:"
+        f" {', '.join(unsigned_contributors)}."
+    )
+
+
+def main():
+    """Entry point."""
+
+    pull_request = get_inputs()
+
+    signed_contributors = get_signed_contributors()
+
+    assert_contributors(pull_request, signed_contributors)
+
+
+if __name__ == "__main__":
+    main()

.github/workflows/validate-existing-contributors.yaml

@@ -0,0 +1,41 @@
+name: Validate Existing Contributors
+
+on:
+  workflow_call:
+
+env:
+  PYTHON_VERSION: 3.11
+  WORKING_DIR: codeforlife-workspace/.github/scripts/python/validate-existing-contributors
+
+jobs:
+  validate-existing-contributors:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 🛫 Checkout Pull Request
+        uses: actions/checkout@v4
+
+      - name: 🔎 View Pull Request's Commits
+        id: view-pr
+        run: echo "PULL_REQUEST=$(gh pr view ${{ github.event.pull_request.number }} --json commits)" >> $GITHUB_OUTPUT
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: 🛫 Checkout Workspace
+        uses: actions/checkout@v4
+        with:
+          repository: ocadotechnology/codeforlife-workspace
+          ref: main
+          path: codeforlife-workspace
+
+      - name: 🐍 Set up Python ${{ env.PYTHON_VERSION }} Environment
+        uses: ocadotechnology/codeforlife-workspace/.github/actions/python/setup-environment@main
+        with:
+          checkout: 'false'
+          python-version: ${{ env.PYTHON_VERSION }}
+          working-directory: ${{ env.WORKING_DIR }}
+
+      - name: 🕵️ Validate Existing Contributors
+        working-directory: ${{ env.WORKING_DIR }}
+        run: pipenv run python .
+        env:
+          PULL_REQUEST: ${{ steps.view-pr.outputs.PULL_REQUEST }}