ci: Use the ci-fairy job to check commit messages

Replace the custom signed-off-by job with one used across multiple fdo
projects. This one also checks a few more things including subject
lengths etc.

We don't want to run it on master so it doesn't fail after merging for
whatever reason (any error should be caught by the MR pipeline anyway).

And we need a higher git depth so ci-fairy can find the merge base.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

.gitlab-ci.yml

@@ -4,6 +4,7 @@ include:
     file:
       - '/templates/fedora.yml'
       - '/templates/debian.yml'
+      - '/templates/ci-fairy.yml'
 
 variables:
   FDO_DISTRIBUTION_TAG: latest
@@ -52,12 +53,18 @@ stages:
 image: $FEDORA_IMAGE
 
 verify_signoff:
+  extends:
+    - .fdo.ci-fairy
   stage: pre-commit
   script:
-    - git fetch origin master
-    - python3 contrib/git-signoff.py
+    - ci-fairy -vv check-commits --signed-off-by --junit-xml=results.xml
   rules:
     - if: $CI_PIPELINE_SOURCE == "merge_request_event"
+  variables:
+    GIT_DEPTH: 100
+  artifacts:
+    reports:
+      junit: results.xml
 
 pre_commit:
   stage: pre-commit

contrib/git-signoff.py

@@ -1,62 +0,0 @@
-#!/usr/bin/env python3
-#
-# SPDX-License-Identifier: GPL-2.0-or-later
-#
-# Verify that all commits added on the current branch (compared to
-# origin/master) contain a properly formatted Signed-off-by tag.
-
-from __future__ import annotations
-
-import re
-import subprocess
-import sys
-
-SIGNOFF_RE = re.compile(r"^Signed-off-by: .+ <.+@.+\..+>$")
-
-
-def get_added_commits() -> list[tuple[str, str]]:
-    result = subprocess.run(
-        ["git", "log", "--format=%H %s", "origin/master..HEAD"],
-        capture_output=True,
-        text=True,
-        check=True,
-    )
-    commits = []
-    for line in result.stdout.strip().splitlines():
-        sha, subject = line.split(" ", 1)
-        commits.append((sha, subject))
-    return commits
-
-
-def get_commit_message(sha: str) -> str:
-    result = subprocess.run(
-        ["git", "log", "-1", "--format=%B", sha],
-        capture_output=True,
-        text=True,
-        check=True,
-    )
-    return result.stdout
-
-
-def main() -> int:
-    commits = get_added_commits()
-    if not commits:
-        print("No commits found between origin/master and HEAD.")
-        return 0
-
-    retval = 0
-    for sha, subject in commits:
-        message = get_commit_message(sha)
-        has_signoff = any(SIGNOFF_RE.match(line) for line in message.splitlines())
-        if not has_signoff:
-            print(
-                f"ERROR: Signed-off-by tag cannot be found in commit "
-                f'{sha[:12]} ("{subject}")'
-            )
-            retval = 1
-
-    return retval
-
-
-if __name__ == "__main__":
-    raise SystemExit(main())