Correlate co-author emails to GitHub usernames and merge with existing contributors

Co-authored-by: zkoppert <[email protected]>

Author: Copilot

README.md

@@ -93,13 +93,13 @@ This action can be configured to authenticate with GitHub App Installation or Pe
 | `END_DATE`              | False                                           | Current Date      | The date at which you want to stop gathering contributor information. Must be later than the `START_DATE`. ie. Aug 2nd, 2023 would be `2023-08-02`                                                                       |
 | `SPONSOR_INFO`          | False                                           | False             | If you want to include sponsor information in the output. This will include the sponsor count and the sponsor URL. This will impact action performance. ie. SPONSOR_INFO = "False" or SPONSOR_INFO = "True"              |
 | `LINK_TO_PROFILE`       | False                                           | True              | If you want to link usernames to their GitHub profiles in the output. ie. LINK_TO_PROFILE = "True" or LINK_TO_PROFILE = "False"                                                                                          |
-| `ACKNOWLEDGE_COAUTHORS` | False                                           | True              | If you want to include co-authors from commit messages as contributors. Co-authors are identified via the `Co-authored-by:` trailer in commit messages. The action will extract GitHub usernames from GitHub noreply emails (e.g., `[email protected]`) or use the full email address for other email domains. This will impact action performance as it requires scanning all commits. ie. ACKNOWLEDGE_COAUTHORS = "True" or ACKNOWLEDGE_COAUTHORS = "False" |
+| `ACKNOWLEDGE_COAUTHORS` | False                                           | True              | If you want to include co-authors from commit messages as contributors. Co-authors are identified via the `Co-authored-by:` trailer in commit messages. The action will correlate co-author emails to GitHub usernames when possible and merge their contributions with existing contributor stats. This will impact action performance as it requires scanning all commits. ie. ACKNOWLEDGE_COAUTHORS = "True" or ACKNOWLEDGE_COAUTHORS = "False" |
 
 **Note**: If `start_date` and `end_date` are specified then the action will determine if the contributor is new. A new contributor is one that has contributed in the date range specified but not before the start date.
 
 **Performance Note:** Using start and end dates will reduce speed of the action by approximately 63X. ie without dates if the action takes 1.7 seconds, it will take 1 minute and 47 seconds.
 
-**Co-authors Note:** When `ACKNOWLEDGE_COAUTHORS` is enabled, the action will scan commit messages for `Co-authored-by:` trailers and include those users as contributors. For GitHub noreply email addresses (e.g., `[email protected]`), the username will be extracted. For other email addresses (e.g., `[email protected]`), the full email address will be used as the contributor identifier. See [GitHub's documentation on creating commits with multiple authors](https://docs.github.com/en/pull-requests/committing-changes-to-your-project/creating-and-editing-commits/creating-a-commit-with-multiple-authors).
+**Co-authors Note:** When `ACKNOWLEDGE_COAUTHORS` is enabled, the action will scan commit messages for `Co-authored-by:` trailers and include those users as contributors. The action attempts to match co-author emails to GitHub usernames by cross-referencing with commit author data. When a match is found, co-author contributions are merged with the existing contributor's stats. If no match is found, the email address itself is used as the contributor identifier. See [GitHub's documentation on creating commits with multiple authors](https://docs.github.com/en/pull-requests/committing-changes-to-your-project/creating-and-editing-commits/creating-a-commit-with-multiple-authors).
 
 ### Example workflows
 

contributors.py

@@ -211,8 +211,6 @@ def get_contributors(
     """
     all_repo_contributors = repo.contributors()
     contributors = []
-    # Track usernames already added as contributors
-    contributor_usernames = set()
 
     try:
         for user in all_repo_contributors:
@@ -247,14 +245,12 @@ def get_contributors(
                 "",
             )
             contributors.append(contributor)
-            contributor_usernames.add(user.login)
 
         # Get co-authors from commit messages if enabled
         if acknowledge_coauthors:
-            coauthor_contributors = get_coauthor_contributors(
-                repo, start_date, end_date, ghe, contributor_usernames
+            contributors = get_coauthor_contributors(
+                repo, start_date, end_date, ghe, contributors
             )
-            contributors.extend(coauthor_contributors)
 
     except Exception as e:
         print(f"Error getting contributors for repository: {repo.full_name}")
@@ -269,22 +265,26 @@ def get_coauthor_contributors(
     start_date: str,
     end_date: str,
     ghe: str,
-    existing_usernames: set,
+    existing_contributors: List[contributor_stats.ContributorStats],
 ) -> List[contributor_stats.ContributorStats]:
     """
     Get contributors who were co-authors on commits in the repository.
 
+    Matches co-author emails to GitHub usernames by looking them up from commit data.
+    Merges co-author contributions with existing contributors when possible.
+
     Args:
         repo (object): The repository object
         start_date (str): The start date of the date range for the contributor list.
         end_date (str): The end date of the date range for the contributor list.
         ghe (str): The GitHub Enterprise URL
-        existing_usernames (set): Set of usernames already added as contributors
+        existing_contributors (List[ContributorStats]): List of existing contributors to merge with
 
     Returns:
-        List[ContributorStats]: A list of ContributorStats objects for co-authors
+        List[ContributorStats]: Updated list with co-author contributions merged
     """
-    coauthor_counts: dict = {}  # username -> count
+    coauthor_counts: dict = {}  # email/username -> count
+    email_to_username: dict = {}  # email -> GitHub username mapping
     endpoint = ghe if ghe else "https://github.com"
 
     try:
@@ -294,42 +294,74 @@ def get_coauthor_contributors(
         else:
             commits = repo.commits()
 
+        # First pass: build email to username mapping and count co-authors
         for commit in commits:
             # Get commit message from the commit object
             commit_message = commit.commit.message if commit.commit else ""
+
+            # Build email to username mapping from commit author info
+            if commit.author and commit.commit and commit.commit.author:
+                author_email = commit.commit.author.get("email", "")
+                if author_email and commit.author.login:
+                    email_to_username[author_email] = commit.author.login
+
             if not commit_message:
                 continue
 
             # Extract co-authors from commit message
             coauthors = get_coauthors_from_message(commit_message)
-            for username in coauthors:
-                if username not in existing_usernames:
-                    coauthor_counts[username] = coauthor_counts.get(username, 0) + 1
+            for identifier in coauthors:
+                coauthor_counts[identifier] = coauthor_counts.get(identifier, 0) + 1
 
     except Exception as e:
         print(f"Error getting co-authors for repository: {repo.full_name}")
         print(e)
-        return []
+        return existing_contributors
 
-    # Create ContributorStats objects for co-authors
-    coauthor_contributors = []
-    for username, count in coauthor_counts.items():
-        if start_date and end_date:
-            commit_url = f"{endpoint}/{repo.full_name}/commits?author={username}&since={start_date}&until={end_date}"
+    # Second pass: merge co-author contributions with existing contributors
+    existing_usernames = {c.username for c in existing_contributors}
+
+    for identifier, count in coauthor_counts.items():
+        # Try to resolve identifier to GitHub username
+        username = None
+
+        # Check if it's already a username (from noreply email)
+        if "@" not in identifier:
+            username = identifier
+        # Check if we can map this email to a known username
+        elif identifier in email_to_username:
+            username = email_to_username[identifier]
         else:
-            commit_url = f"{endpoint}/{repo.full_name}/commits?author={username}"
-
-        contributor = contributor_stats.ContributorStats(
-            username,
-            False,
-            "",  # No avatar URL available for co-authors
-            count,
-            commit_url,
-            "",
-        )
-        coauthor_contributors.append(contributor)
+            # Use email as fallback identifier
+            username = identifier
+
+        # Check if this user already exists in contributors
+        merged = False
+        for contributor in existing_contributors:
+            if contributor.username == username:
+                # Merge the co-author contributions with existing contributor
+                contributor.contribution_count += count
+                merged = True
+                break
+
+        # If not merged, create a new contributor entry
+        if not merged and username not in existing_usernames:
+            if start_date and end_date:
+                commit_url = f"{endpoint}/{repo.full_name}/commits?author={username}&since={start_date}&until={end_date}"
+            else:
+                commit_url = f"{endpoint}/{repo.full_name}/commits?author={username}"
+
+            contributor = contributor_stats.ContributorStats(
+                username,
+                False,
+                "",  # No avatar URL available for co-authors without user lookup
+                count,
+                commit_url,
+                "",
+            )
+            existing_contributors.append(contributor)
 
-    return coauthor_contributors
+    return existing_contributors
 
 
 if __name__ == "__main__":

test_contributors.py

@@ -317,19 +317,25 @@ def test_get_coauthor_contributors(self):
 
 Co-authored-by: Alice <[email protected]>
 """
+        mock_commit1.author = MagicMock()
+        mock_commit1.author.login = "alice"
+        mock_commit1.commit.author = {"email": "[email protected]"}
 
         mock_commit2 = MagicMock()
         mock_commit2.commit.message = """Bug fix
 
 Co-authored-by: Alice <[email protected]>
 Co-authored-by: Bob <[email protected]>
 """
+        mock_commit2.author = MagicMock()
+        mock_commit2.author.login = "bob"
+        mock_commit2.commit.author = {"email": "[email protected]"}
 
         mock_repo.commits.return_value = [mock_commit1, mock_commit2]
 
-        existing_usernames = set()
+        existing_contributors = []
         result = get_coauthor_contributors(
-            mock_repo, "2022-01-01", "2022-12-31", "", existing_usernames
+            mock_repo, "2022-01-01", "2022-12-31", "", existing_contributors
         )
 
         # Alice should have count 2, Bob should have count 1
@@ -345,9 +351,9 @@ def test_get_coauthor_contributors(self):
             elif contributor.username == "bob":
                 self.assertEqual(contributor.contribution_count, 1)
 
-    def test_get_coauthor_contributors_excludes_existing(self):
+    def test_get_coauthor_contributors_merges_with_existing(self):
         """
-        Test that get_coauthor_contributors excludes already existing contributors.
+        Test that get_coauthor_contributors merges with existing contributors.
         """
         mock_repo = MagicMock()
         mock_repo.full_name = "owner/repo"
@@ -356,20 +362,39 @@ def test_get_coauthor_contributors_excludes_existing(self):
         mock_commit.commit.message = """Feature
 
 Co-authored-by: Alice <[email protected]>
-Co-authored-by: Bob <bob@users.noreply.github.com>
+Co-authored-by: Bob <bob@example.com>
 """
+        mock_commit.author = MagicMock()
+        mock_commit.author.login = "alice"
+        mock_commit.commit.author = {"email": "[email protected]"}
 
         mock_repo.commits.return_value = [mock_commit]
 
-        # Alice is already a contributor
-        existing_usernames = {"alice"}
+        # Alice is already a contributor with 5 commits
+        existing_contributors = [
+            ContributorStats(
+                "alice",
+                False,
+                "https://avatars.githubusercontent.com/u/",
+                5,
+                "url1",
+                "",
+            )
+        ]
         result = get_coauthor_contributors(
-            mock_repo, "2022-01-01", "2022-12-31", "", existing_usernames
+            mock_repo, "2022-01-01", "2022-12-31", "", existing_contributors
         )
 
-        # Only Bob should be in the result
-        self.assertEqual(len(result), 1)
-        self.assertEqual(result[0].username, "bob")
+        # Alice should be merged (5 + 1 = 6), Bob should be added
+        self.assertEqual(len(result), 2)
+        usernames = {c.username for c in result}
+        self.assertIn("alice", usernames)
+        self.assertIn("[email protected]", usernames)
+
+        # Check Alice's count was incremented
+        for contributor in result:
+            if contributor.username == "alice":
+                self.assertEqual(contributor.contribution_count, 6)
 
     @patch("contributors.get_coauthor_contributors")
     def test_get_contributors_with_acknowledge_coauthors(
@@ -386,15 +411,22 @@ def test_get_contributors_with_acknowledge_coauthors(
         mock_repo.contributors.return_value = [mock_user]
         mock_repo.full_name = "owner/repo"
 
-        mock_coauthor = ContributorStats(
-            "coauthor",
-            False,
-            "",
-            1,
-            "https://github.com/owner/repo/commits?author=coauthor&since=2022-01-01&until=2022-12-31",
-            "",
-        )
-        mock_get_coauthor_contributors.return_value = [mock_coauthor]
+        # Mock the return value to include both existing and new contributor
+        def side_effect(repo, start, end, ghe, existing):  # pylint: disable=unused-argument
+            # Add a coauthor to the existing list
+            existing.append(
+                ContributorStats(
+                    "coauthor",
+                    False,
+                    "",
+                    1,
+                    "https://github.com/owner/repo/commits?author=coauthor&since=2022-01-01&until=2022-12-31",
+                    "",
+                )
+            )
+            return existing
+
+        mock_get_coauthor_contributors.side_effect = side_effect
 
         result = get_contributors(
             mock_repo, "2022-01-01", "2022-12-31", "", acknowledge_coauthors=True