.github/workflows: check commit description format

Check PR commit subjects for the standard format we use "pkg/name: description of the change".
Check PR commit bodies for at most 120 characters.

1 files changed, 42 insertions, 0 deletions

diff --git a/tools/check-commits.sh b/tools/check-commits.sh
new file mode 100755
index 000000000..e2734d3dd
--- /dev/null
+++ b/tools/check-commits.sh
@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Copyright 2020 syzkaller project authors. All rights reserved.
+# Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+set -e
+
+# GITHUB_PR_BASE_SHA is exported in .github/workflows/ci.yml for pull requests.
+# If it is not set, check against refs/heads/master (presumably a local run),
+# otherwise skip the checks (presumably CI run on a fork commit).
+if [ "${GITHUB_PR_BASE_SHA}" == "" ]; then
+	GITHUB_PR_BASE_SHA="refs/heads/master"
+	HAVE_MASTER=0
+	git show-ref ${GITHUB_PR_BASE_SHA} 1>/dev/null 2>&1 || HAVE_MASTER=$?
+	if [[ HAVE_MASTER -ne 0 ]]; then
+		echo "skipping commit checks: GITHUB_PR_BASE_SHA is not set and ${GITHUB_PR_BASE_SHA} does not exist"
+		exit 0
+	fi
+fi
+
+COMMITS=0
+FAILED=""
+HASHES=$(git log --format="%h" ${GITHUB_PR_BASE_SHA}..HEAD)
+for HASH in ${HASHES}; do
+	((COMMITS+=1))
+	SUBJECT=$(git show --format="%s" --no-patch ${HASH})
+	BODY=$(git show --format="%B" --no-patch ${HASH})
+	if ! [[ ${SUBJECT} =~ ^(([a-z0-9/_.-]+|Makefile|CONTRIBUTORS|README.md)(, )?)+:\ [a-z].+[^.]$ ]]; then
+		echo "##[error]Wrong commit subject format: '${SUBJECT}'.\
+ Please use 'main/affected/package: short change description'.\
+ See docs/contributing.md for details."
+		FAILED="1"
+	fi
+	LONGLINE='[^\
+]{121}'
+	if [[ ${BODY} =~ ${LONGLINE} ]]; then
+		echo "##[error]Please limit commit description line length to 120 characters."
+		echo "${BODY}"
+		FAILED="1"
+	fi
+done
+if [ "$FAILED" != "" ]; then exit 1; fi
+echo "$COMMITS commits checked for format style"