Allow mentioning fixed issues in the changelog

Also allow mentioning the PR like now. The numbers of issues must match
the issues referenced by the PR.

.github/workflows/changelog-check.yaml

@@ -22,15 +22,26 @@ jobs:
     name: Check for file with CHANGELOG entry
     runs-on: ubuntu-latest
     steps:
+      - name: Install Linux Dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install pip
+
+      - name: Install Python Dependencies
+        run: |
+          pip install PyGithub
+
       - name: Checkout source
         uses: actions/checkout@v3
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0
+
       - name: Check if the pull request adds file in ".unreleased" folder
         shell: bash --norc --noprofile {0}
         env:
           BODY: ${{ github.event.pull_request.body }}
+          GITHUB_TOKEN: ${{ secrets.ORG_AUTOMATION_TOKEN }}
           PR_NUMBER: ${{ github.event.pull_request.number }}
         run: |
           folder=".unreleased"

scripts/check_changelog_format.py

@@ -4,6 +4,68 @@ import sys
 import re
 import os
 
+import github  # this is PyGithub.
+
+import requests
+import string
+
+
+def run_query(query):
+    """A simple function to use requests.post to make the GraphQL API call."""
+
+    request = requests.post(
+        "https://api.github.com/graphql",
+        json={"query": query},
+        headers={"Authorization": f'Bearer {os.environ.get("GITHUB_TOKEN")}'},
+        timeout=20,
+    )
+    response = request.json()
+
+    # Have to work around the unique GraphQL convention of returning 200 for errors.
+    if request.status_code != 200 or "errors" in response:
+        raise ValueError(
+            f"Query failed to run by returning code of {request.status_code}."
+            f"\nQuery: '{query}'"
+            f"\nResponse: '{request.json()}'"
+        )
+
+    return response
+
+
+def get_referenced_issues(pr_number):
+    """Get the numbers of issue fixed by the given pull request."""
+
+    ref_result = run_query(
+        string.Template(
+            """
+        query {
+            repository(owner: "timescale", name: "timescaledb") {
+              pullRequest(number: $pr_number) {
+                closingIssuesReferences(first: 100) {
+                  edges {
+                    node {
+                      number
+                    }
+                  }
+                }
+              }
+            }
+          }
+          """
+        ).substitute({"pr_number": pr_number})
+    )
+
+    # The above returns {'data': {'repository': {'pullRequest': {'closingIssuesReferences': {'edges': [{'node': {'number': 4944}}]}}}}}
+
+    ref_edges = ref_result["data"]["repository"]["pullRequest"][
+        "closingIssuesReferences"
+    ]["edges"]
+
+    if not ref_edges:
+        return []
+
+    return [edge["node"]["number"] for edge in ref_edges if edge]
+
 
 # Check if a line matches any of the specified patterns
 def is_valid_line(line):
@@ -15,28 +77,63 @@ def is_valid_line(line):
 
 
 def main():
+    github_obj = github.Github(os.environ.get("GITHUB_TOKEN"))
+    repo = github_obj.get_repo("timescale/timescaledb")
     # Get the file name from the command line argument
-    if len(sys.argv) > 1:
-        file_name = sys.argv[1]
-        pr_number_seen = False
-        pr_num_str = f'#{os.environ["PR_NUMBER"]} '
-        # Read the file and check non-empty lines
-        with open(file_name, "r", encoding="utf-8") as file:
-            for line in file:
-                line = line.strip()
-                pr_number_seen |= pr_num_str in line
-                if line and not is_valid_line(line):
-                    print(f'Invalid entry in change log: "{line}"')
-                    sys.exit(1)
-        if not pr_number_seen:
-            print(
-                f'Expected that the changelog contains a reference to the PR: "{pr_num_str}"'
-            )
-            sys.exit(1)
-    else:
+    if len(sys.argv) != 2:
         print("Please provide a file name as a command-line argument.")
         sys.exit(1)
-    sys.exit(0)
+
+    file_name = sys.argv[1]
+    this_pr_number = int(os.environ["PR_NUMBER"])
+    pr_issues = set(get_referenced_issues(this_pr_number))
+
+    # Read the file and check non-empty lines
+    changelog_issues = set()
+    with open(file_name, "r", encoding="utf-8") as file:
+        for line in file:
+            line = line.strip()
+            if not is_valid_line(line):
+                print(f'Invalid entry in change log: "{line}"')
+                sys.exit(1)
+
+            # The referenced issue number should be valid.
+            for issue_number in re.findall("#([0-9]+)", line):
+                issue_number = int(issue_number)
+                try:
+                    issue = repo.get_issue(number=issue_number)
+                except github.UnknownObjectException:
+                    print(
+                        f"The changelog entry references an invalid issue #{issue_number}:\n{line}"
+                    )
+                    sys.exit(1)
+
+                as_pr = None
+                try:
+                    as_pr = issue.as_pull_request()
+                except github.UnknownObjectException:
+                    # Not a pull request
+                    pass
+
+                # Accept references to PR itself.
+                if as_pr:
+                    if issue_number != this_pr_number:
+                        print(
+                            f"The changelog for PR #{this_pr_number} references another PR #{issue_number}"
+                        )
+                        sys.exit(1)
+                    changelog_issues = pr_issues
+                else:
+                    changelog_issues.add(issue_number)
+
+    if changelog_issues != pr_issues:
+        print(
+            "Instead of "
+            + (f"the issues {pr_issues}" if pr_issues else "no issues")
+            + f" linked to the PR #{this_pr_number}, the changelog references "
+            + (f"the issues {changelog_issues}" if changelog_issues else "no issues")
+        )
+        sys.exit(1)
 
 
 if __name__ == "__main__":