[PATCH v1 4/6] gitlab: skip checkpatch.pl checks if no commit delta on branch

["Alex Bennée" <alex.bennee@linaro.org>]

From: Daniel P. Berrangé <berrange@redhat.com>

If the current branch is synced to the current upstream git master,
there are no commits that need checking. This causes checkpatch.pl
to print an error that it found no commits. We need to avoid calling
checkpatch.pl in this case.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20201019143537.283094-2-berrange@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 .gitlab-ci.d/check-patch.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/.gitlab-ci.d/check-patch.py b/.gitlab-ci.d/check-patch.py
index 5a14a25b13..0ff30ee077 100755
--- a/.gitlab-ci.d/check-patch.py
+++ b/.gitlab-ci.d/check-patch.py
@@ -33,8 +33,16 @@ ancestor = subprocess.check_output(["git", "merge-base",
 
 ancestor = ancestor.strip()
 
+log = subprocess.check_output(["git", "log", "--format=%H %s",
+                               ancestor + "..."],
+                              universal_newlines=True)
+
 subprocess.check_call(["git", "remote", "rm", "check-patch"])
 
+if log == "":
+    print("\nNo commits since %s, skipping checks\n" % ancestor)
+    sys.exit(0)
+
 errors = False
 
 print("\nChecking all commits since %s...\n" % ancestor)
-- 
2.20.1