[PATCH 1/3] gitlab: add a CI job for running checkpatch.pl

["Daniel P. Berrangé" <berrange@redhat.com>]

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>
---
 .gitlab-ci.d/check-patch.py | 48 +++++++++++++++++++++++++++++++++++++
 .gitlab-ci.yml              | 12 ++++++++++
 2 files changed, 60 insertions(+)
 create mode 100755 .gitlab-ci.d/check-patch.py

diff --git a/.gitlab-ci.d/check-patch.py b/.gitlab-ci.d/check-patch.py
new file mode 100755
index 0000000000..5a14a25b13
--- /dev/null
+++ b/.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)
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a18e18b57e..3ed724c720 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -369,3 +369,15 @@ check-crypto-only-gnutls:
   variables:
     IMAGE: centos7
     MAKE_CHECK_ARGS: check
+
+
+check-patch:
+  stage: test
+  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
-- 
2.26.2