Extended checks and docs for proper commit message format and edition.

Thanks to Tim Schilling for the review.

Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>

2 files changed, 37 insertions, 1 deletions

diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index 7efa2f1384..0d30fbbced 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -16,7 +16,7 @@ Provide a concise overview of the issue or rationale behind the proposed changes
 - [ ] This PR follows the [contribution guidelines](https://docs.djangoproject.com/en/stable/internals/contributing/writing-code/submitting-patches/).
 - [ ] This PR **does not** disclose a security vulnerability (see [vulnerability reporting](https://docs.djangoproject.com/en/stable/internals/security/)).
 - [ ] This PR targets the `main` branch. <!-- Backports will be evaluated and done by mergers, when necessary. -->
-- [ ] The commit message is written in past tense, mentions the ticket number, and ends with a period.
+- [ ] The commit message is written in past tense, mentions the ticket number, and ends with a period (see [guidelines](https://docs.djangoproject.com/en/dev/internals/contributing/committing-code/#committing-guidelines)).
 - [ ] I have checked the "Has patch" ticket flag in the Trac system.
 - [ ] I have added or updated relevant tests.
 - [ ] I have added or updated relevant docs, including release notes if applicable.
diff --git a/.github/workflows/check_commit_messages.yml b/.github/workflows/check_commit_messages.yml
index 32f1558464..590cc58de3 100644
--- a/.github/workflows/check_commit_messages.yml
+++ b/.github/workflows/check_commit_messages.yml
@@ -68,3 +68,39 @@ jobs:
           fi
 
           echo "✅ All commits have the required prefix."
+
+  check-commit-suffix:
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+
+      - name: Fetch relevant branches
+        run: |
+          git fetch origin $BASE:base
+          git fetch origin pull/${{ github.event.pull_request.number }}/head:pr
+
+      - name: Check commit messages suffix
+        run: |
+          COMMITS=$(git rev-list base..pr)
+          echo "Checking commit messages for trailing period"
+          FAIL=0
+          for SHA in $COMMITS; do
+            MSG=$(git log -1 --pretty=%s $SHA)
+            echo "Checking commit $SHA: $MSG"
+            if [[ "${MSG: -1}" != "." ]]; then
+              echo "❌ Commit $SHA must end with a period."
+              echo "Refer to the guidelines linked in the PR checklist for commit message format."
+              echo "For how to rewrite commit messages, see https://docs.djangoproject.com/en/dev/internals/contributing/writing-code/working-with-git/#editing-commit-messages"
+              FAIL=1
+            fi
+          done
+
+          if [[ $FAIL -eq 1 ]]; then
+            echo "One or more commit messages are missing a trailing period."
+            exit 1
+          fi
+
+          echo "✅ All commits have the required trailing period."