Merge branch 'kn/ci-clang-format' into ps/doc-more-c-coding-guidelines

* 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

Author: gitster

.clang-format

@@ -72,6 +72,10 @@ AlwaysBreakAfterReturnType: None
 BinPackArguments: true
 BinPackParameters: true
 
+# Add no space around the bit field
+# unsigned bf:2;
+BitFieldColonSpacing: None
+
 # Attach braces to surrounding context except break before braces on function
 # definitions.
 # void foo()
@@ -96,6 +100,12 @@ BreakStringLiterals: false
 # Switch statement body is always indented one level more than case labels.
 IndentCaseLabels: false
 
+# Indents directives before the hash.
+# #if FOO
+# #  include <foo>
+# #endif
+IndentPPDirectives: AfterHash
+
 # Don't indent a function definition or declaration if it is wrapped after the
 # type
 IndentWrappedFunctionNames: false
@@ -108,11 +118,18 @@ PointerAlignment: Right
 # x = (int32)y;    not    x = (int32) y;
 SpaceAfterCStyleCast: false
 
+# No space is inserted after the logical not operator
+SpaceAfterLogicalNot: false
+
 # Insert spaces before and after assignment operators
 # int a = 5;    not    int a=5;
 # a += 42;             a+=42;
 SpaceBeforeAssignmentOperators: true
 
+# Spaces will be removed before case colon.
+# case 1: break;    not     case 1 : break;
+SpaceBeforeCaseColon: false
+
 # Put a space before opening parentheses only after control statement keywords.
 # void f() {
 #   if (true) {
@@ -124,6 +141,14 @@ SpaceBeforeParens: ControlStatements
 # Don't insert spaces inside empty '()'
 SpaceInEmptyParentheses: false
 
+# No space before first '[' in arrays
+# int a[5][5];     not      int a [5][5];
+SpaceBeforeSquareBrackets: false
+
+# No space will be inserted into {}
+# while (true) {}    not    while (true) { }
+SpaceInEmptyBlock: false
+
 # The number of spaces before trailing line comments (// - comments).
 # This does not affect trailing block comments (/* - comments).
 SpacesBeforeTrailingComments: 1

.github/workflows/check-style.yml

@@ -0,0 +1,34 @@
+name: check-style
+
+# Get the repository with all commits to ensure that we can analyze
+# all of the commits contributed via the Pull Request.
+
+on:
+  pull_request:
+    types: [opened, synchronize]
+
+# Avoid unnecessary builds. Unlike the main CI jobs, these are not
+# ci-configurable (but could be).
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check-style:
+    env:
+      CC: clang
+      jobname: ClangFormat
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+
+    - run: ci/install-dependencies.sh
+
+    - name: git clang-format
+      continue-on-error: true
+      id: check_out
+      run: |
+        ./ci/run-style-check.sh \
+          "${{github.event.pull_request.base.sha}}"

.gitlab-ci.yml

@@ -118,8 +118,31 @@ check-whitespace:
   image: ubuntu:latest
   before_script:
     - ./ci/install-dependencies.sh
+  # Since $CI_MERGE_REQUEST_TARGET_BRANCH_SHA is only defined for merged
+  # pipelines, we fallback to $CI_MERGE_REQUEST_DIFF_BASE_SHA, which should
+  # be defined in all pipelines.
   script:
-    - ./ci/check-whitespace.sh "$CI_MERGE_REQUEST_TARGET_BRANCH_SHA"
+    - |
+      R=${CI_MERGE_REQUEST_TARGET_BRANCH_SHA-${CI_MERGE_REQUEST_DIFF_BASE_SHA:?}} || exit
+      ./ci/check-whitespace.sh "$R"
+  rules:
+    - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
+
+check-style:
+  image: ubuntu:latest
+  allow_failure: true
+  variables:
+    CC: clang
+    jobname: ClangFormat
+  before_script:
+    - ./ci/install-dependencies.sh
+  # Since $CI_MERGE_REQUEST_TARGET_BRANCH_SHA is only defined for merged
+  # pipelines, we fallback to $CI_MERGE_REQUEST_DIFF_BASE_SHA, which should
+  # be defined in all pipelines.
+  script:
+    - |
+      R=${CI_MERGE_REQUEST_TARGET_BRANCH_SHA-${CI_MERGE_REQUEST_DIFF_BASE_SHA:?}} || exit
+      ./ci/run-style-check.sh "$R"
   rules:
     - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
 

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}"
 

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 \

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"