gitlab: add a CI job for running checkpatch.pl

This job is advisory since it is expected that certain patches will fail
the style checks and checkpatch.pl provides no way to mark exceptions to
the rules.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200918132903.1848939-2-berrange@redhat.com>
[thuth: Use "stage: build" to let it run earlier]
Signed-off-by: Thomas Huth <thuth@redhat.com>

.gitlab-ci.d/check-patch.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+#
+# check-patch.py: run checkpatch.pl across all commits in a branch
+#
+# Copyright (C) 2020 Red Hat, Inc.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+import os
+import os.path
+import sys
+import subprocess
+
+namespace = "qemu-project"
+if len(sys.argv) >= 2:
+    namespace = sys.argv[1]
+
+cwd = os.getcwd()
+reponame = os.path.basename(cwd)
+repourl = "https://gitlab.com/%s/%s.git" % (namespace, reponame)
+
+# GitLab CI environment does not give us any direct info about the
+# base for the user's branch. We thus need to figure out a common
+# ancestor between the user's branch and current git master.
+subprocess.check_call(["git", "remote", "add", "check-patch", repourl])
+subprocess.check_call(["git", "fetch", "check-patch", "master"],
+                      stdout=subprocess.DEVNULL,
+                      stderr=subprocess.DEVNULL)
+
+ancestor = subprocess.check_output(["git", "merge-base",
+                                    "check-patch/master", "HEAD"],
+                                   universal_newlines=True)
+
+ancestor = ancestor.strip()
+
+subprocess.check_call(["git", "remote", "rm", "check-patch"])
+
+errors = False
+
+print("\nChecking all commits since %s...\n" % ancestor)
+
+ret = subprocess.run(["scripts/checkpatch.pl", ancestor + "..."])
+
+if ret.returncode != 0:
+    print("    ❌ FAIL one or more commits failed scripts/checkpatch.pl")
+    sys.exit(1)
+
+sys.exit(0)

.gitlab-ci.yml

@@ -399,3 +399,15 @@ check-crypto-only-gnutls:
   variables:
     IMAGE: centos7
     MAKE_CHECK_ARGS: check
+
+
+check-patch:
+  stage: build
+  image: $CI_REGISTRY_IMAGE/qemu/centos8:latest
+  script: .gitlab-ci.d/check-patch.py
+  except:
+    variables:
+      - $CI_PROJECT_NAMESPACE == 'qemu-project' && $CI_COMMIT_BRANCH == 'master'
+  variables:
+    GIT_DEPTH: 1000
+  allow_failure: true