Merge branch 'kn/ci-clang-format'

A CI job that use clang-format to check coding style issues in new
code has been added.

* kn/ci-clang-format:
  ci/style-check: add `RemoveBracesLLVM` in CI job
  check-whitespace: detect if no base_commit is provided
  ci: run style check on GitHub and GitLab
  clang-format: formalize some of the spacing rules
  clang-format: avoid spacing around bitfield colon
  clang-format: indent preprocessor directives after hash

3 files changed, 37 insertions, 2 deletions

diff --git a/ci/check-whitespace.sh b/ci/check-whitespace.sh
index db399097a5..c40804394c 100755
--- a/ci/check-whitespace.sh
+++ b/ci/check-whitespace.sh
@@ -9,7 +9,7 @@ baseCommit=$1
 outputFile=$2
 url=$3
 
-if test "$#" -ne 1 && test "$#" -ne 3
+if test "$#" -ne 1 && test "$#" -ne 3 || test -z "$1"
 then
 	echo "USAGE: $0 <BASE_COMMIT> [<OUTPUT_FILE> <URL>]"
 	exit 1
@@ -21,6 +21,12 @@ commitText=
 commitTextmd=
 goodParent=
 
+if ! git rev-parse --quiet --verify "${baseCommit}"
+then
+    echo "Invalid <BASE_COMMIT> '${baseCommit}'"
+    exit 1
+fi
+
 while read dash sha etc
 do
 	case "${dash}" in
@@ -67,7 +73,7 @@ then
 		goodParent=${baseCommit: 0:7}
 	fi
 
-	echo "A whitespace issue was found in onen of more of the commits."
+	echo "A whitespace issue was found in one or more of the commits."
 	echo "Run the following command to resolve whitespace issues:"
 	echo "git rebase --whitespace=fix ${goodParent}"
 
diff --git a/ci/install-dependencies.sh b/ci/install-dependencies.sh
index 6ec0f85972..fb34ced8f0 100755
--- a/ci/install-dependencies.sh
+++ b/ci/install-dependencies.sh
@@ -87,6 +87,10 @@ macos-*)
 esac
 
 case "$jobname" in
+ClangFormat)
+	sudo apt-get -q update
+	sudo apt-get -q -y install clang-format
+	;;
 StaticAnalysis)
 	sudo apt-get -q update
 	sudo apt-get -q -y install coccinelle libcurl4-openssl-dev libssl-dev \
diff --git a/ci/run-style-check.sh b/ci/run-style-check.sh
new file mode 100755
index 0000000000..6cd4b1d934
--- /dev/null
+++ b/ci/run-style-check.sh
@@ -0,0 +1,25 @@
+#!/bin/sh
+#
+# Perform style check
+#
+
+baseCommit=$1
+
+# Remove optional braces of control statements (if, else, for, and while)
+# according to the LLVM coding style. This avoids braces on simple
+# single-statement bodies of statements but keeps braces if one side of
+# if/else if/.../else cascade has multi-statement body.
+#
+# As this rule comes with a warning [1], we want to experiment with it
+# before adding it in-tree. since the CI job for the style check is allowed
+# to fail, appending the rule here allows us to validate its efficacy.
+# While also ensuring that end-users are not affected directly.
+#
+# [1]: https://clang.llvm.org/docs/ClangFormatStyleOptions.html#removebracesllvm
+{
+	cat .clang-format
+	echo "RemoveBracesLLVM: true"
+} >/tmp/clang-format-rules
+
+git clang-format --style=file:/tmp/clang-format-rules \
+	--diff --extensions c,h "$baseCommit"