.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.

.github/workflows/ci.yml

@@ -15,6 +15,9 @@ jobs:
         uses: actions/checkout@v2
         with:
           path: gopath/src/github.com/google/syzkaller
+          # This is needed for tools/check-commits.sh
+          ref: ${{ github.event.pull_request.head.sha }}
+          fetch-depth: 100
       # Caches everything in .cache dir, in partiuclar we want to cache go-build and golangci-lint stuff.
       # For reference see:
       # https://help.github.com/en/actions/configuring-and-managing-workflows/caching-dependencies-to-speed-up-workflows#using-the-cache-action
@@ -25,6 +28,8 @@ jobs:
           key: cache
       # Run make presubmit_smoke.
       - name: run
+        env:
+          GITHUB_PR_BASE_SHA: ${{ github.event.pull_request.base.sha }}
         run: gopath/src/github.com/google/syzkaller/.github/workflows/run.sh syz-env make presubmit_smoke
       # Upload coverage report to codecov.io. For reference see:
       # https://github.com/codecov/codecov-action/blob/master/README.md

Makefile

@@ -102,7 +102,7 @@ endif
 	bin/syz-extract bin/syz-fmt \
 	extract generate generate_go generate_sys \
 	format format_go format_cpp format_sys \
-	tidy test test_race check_copyright check_language check_links check_diff \
+	tidy test test_race check_copyright check_language check_links check_diff check_commits \
 	presubmit presubmit_parallel clean
 
 all: host target
@@ -265,7 +265,7 @@ presubmit:
 
 presubmit_smoke:
 	$(MAKE) generate
-	$(MAKE) -j100 check_diff check_copyright check_language check_links presubmit_build
+	$(MAKE) -j100 check_commits check_diff check_copyright check_language check_links presubmit_build
 	$(MAKE) test
 
 presubmit_build:
@@ -342,6 +342,9 @@ check_copyright:
 check_language:
 	./tools/check-language.sh
 
+check_commits:
+	./tools/check-commits.sh
+
 check_links:
 	python ./tools/check_links.py $$(pwd) $$(ls ./*.md; find ./docs/ -name '*.md')
 

docs/contributing.md

@@ -33,6 +33,15 @@ the problem you are solving and how it is solved.
 
 `dir/path` is a relative path to the main dir this commit changes
 (look at examples in the [commit history](https://github.com/google/syzkaller/commits/master)).
+If several packages/dirs are significantly affected, then the following format is allowed:
+```
+dir1/path1, dir2/path2: one-line description
+```
+Though, dirs should not be included if they have only minor changes.
+For pervasive changes the following format is allowed:
+```
+all: one-line description
+```
 
 Please pay attention to punctuation. In particular:
 
@@ -40,6 +49,8 @@ Please pay attention to punctuation. In particular:
 - There is *no dot* at the end of `one-line description`.
 - `Extended multi-line description` is full English sentences with Capital letters and dots.
 
+Commit message line length is limited to 120 characters.
+
 Also:
 
 - If you commit fixes an issue, please include `Fixes #NNN` line into commit message

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"

tools/syz-env

@@ -64,6 +64,7 @@ docker run \
 	--env FUZZIT_API_KEY \
 	--env GITHUB_REF \
 	--env GITHUB_SHA \
+	--env GITHUB_PR_BASE_SHA \
 	--env CI \
 	${DOCKERARGS[@]} \
 	gcr.io/syzkaller/${IMAGE} -c "$COMMAND"