ci: let Dependabot pull requests skip the description template

CONTRIBUTING.md

@@ -65,7 +65,7 @@ On Windows with an NVIDIA GPU some tests are skipped by design (VideoOut tests w
 ### Review and checks
 
 - `main` only changes through pull requests. Force pushes and deletion of `main` are blocked for everyone.
-- Every pull request needs an approving review from the code owner ([.github/CODEOWNERS](.github/CODEOWNERS)) and these checks to pass: **Conventions** (`tools/check_conventions.py`, run from the base branch without executing your code), **Relinker on Linux** and **Windows build and tests**. A pull request that only changes documentation skips the two builds.
+- Every pull request needs an approving review from the code owner ([.github/CODEOWNERS](.github/CODEOWNERS)) and these checks to pass: **Conventions** (`tools/check_conventions.py`, run from the base branch without executing your code), **Relinker on Linux** and **Windows build and tests**. A pull request that only changes documentation skips the two builds. Dependabot's pull requests skip the description template, but their title is still checked.
 - Workflows of a pull request from a fork run only after the maintainer has read the changes and approved the run. Changes to `.github/workflows/` get extra scrutiny.
 - All review conversations must be resolved before merging.
 

tools/check_conventions.py

@@ -346,6 +346,8 @@ def env_reference(self):
     def pull_request(self, title, body):
         if not CONVENTIONAL.match(title):
             self.report("pr-title", "", 0, title)
+        if body is None:
+            return
         body = re.sub(r"<!--.*?-->", "", body or "", flags=re.S)
         sections = dict(zip(SECTION.findall(body), SECTION.split(body)[2::2]))
         for name in ("What", "Tested", "Checklist"):
@@ -360,6 +362,11 @@ def pull_request(self, title, body):
             self.report("pr-template", "", 0, "fill Depends on with #N or none")
 
 
+def dependabot(pr):
+    user = pr.get("user") or {}
+    return user.get("login") == "dependabot[bot]" and user.get("type") == "Bot"
+
+
 def utf8(data):
     try:
         data.decode("utf-8")
@@ -595,7 +602,7 @@ def output(check, repo):
     check.env_reference()
     pr = json.load(open(args.event, encoding="utf-8")).get("pull_request") if args.event else None
     if pr:
-        check.pull_request(pr["title"], pr["body"])
+        check.pull_request(pr["title"], None if dependabot(pr) else pr["body"])
     elif args.title is not None or args.body:
         check.pull_request(args.title or "", open(args.body, encoding="utf-8-sig").read() if args.body else "")
     raise SystemExit(output(check, os.environ.get("GITHUB_REPOSITORY", "boykopovar/AnyPS5")))

tools/tests/test_check_conventions_pr_template.py

@@ -1,3 +1,4 @@
+import json
 import os
 import re
 import subprocess
@@ -125,5 +126,34 @@ def test_title_must_be_conventional(self):
                 self.assertIn("[pr-title] Pull request title is not Conventional Commits", result.stdout)
 
 
+    def run_event(self, user, title="ci: bump actions/checkout", text="Bumps actions/checkout from 6 to 7."):
+        event = {"pull_request": {"title": title, "body": text, "user": user}}
+        (self.root / "event.json").write_text(json.dumps(event), encoding="utf-8")
+        result = subprocess.run(
+            [sys.executable, "-I", str(CHECKER), "--base", "HEAD", "--head", "HEAD", "--event", "event.json"],
+            cwd=self.root, capture_output=True, text=True, encoding="utf-8",
+            env={key: value for key, value in os.environ.items()
+                 if key not in ("GITHUB_EVENT_PATH", "GITHUB_STEP_SUMMARY", "GITHUB_ACTIONS")},
+        )
+        return result, [line[len(PREFIX):] for line in result.stdout.splitlines() if line.startswith(PREFIX)]
+
+    def test_dependabot_pull_request_skips_the_template(self):
+        result, findings = self.run_event({"login": "dependabot[bot]", "type": "Bot"})
+        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+        self.assertEqual(findings, [])
+
+    def test_dependabot_title_is_still_checked(self):
+        result, _ = self.run_event({"login": "dependabot[bot]", "type": "Bot"}, title="Bump actions/checkout")
+        self.assertEqual(result.returncode, 1, result.stdout)
+        self.assertIn("[pr-title] Pull request title is not Conventional Commits", result.stdout)
+
+    def test_other_authors_of_the_same_description_fill_the_template(self):
+        for user in ({"login": "someone", "type": "User"}, {"login": "dependabot[bot]", "type": "User"},
+                     {"login": "renovate[bot]", "type": "Bot"}, None):
+            with self.subTest(user=user):
+                result, findings = self.run_event(user)
+                self.assertEqual(result.returncode, 1, result.stdout)
+                self.assertIn("section 'What' is missing or empty", findings)
+
 if __name__ == "__main__":
     unittest.main()