ci: Move to clang-format version 18

This makes use of the fact that we have moved CI to Ubuntu 24.04, and
are no longer constrained to the old versions offered by Ubuntu 20.04.

Please note: clang-format-18 does return an non-zero exit code when
changes have been found. For this reason, it gets now run in a subshell
which has the pipefail option disabled.

Author: rettichschnidi

README.md

@@ -128,12 +128,12 @@ Wakaama provides a simple CLI library. It can be enabled with:
   - Version control system: Git (and a GitHub account)
   - Git commit message linter: gitlint
   - Build system: ninja
-  - C code formatting: clang-format, version 14
+  - C code formatting: clang-format, version 18
   - CMake list files formatting: cmake-format, version 0.6.13
   - Unit testing: CUnit
 
-On Ubuntu 20.04, used in CI, the dependencies can be installed as such:
-- `apt install build-essential clang-format clang-format-14 clang-tools-14 cmake gcovr git libcunit1-dev ninja-build python3-pip`
+On Ubuntu 24.04, used in CI, the dependencies can be installed as such:
+- `apt install build-essential clang-format clang-format-18 clang-tools-18 cmake gcovr git libcunit1-dev ninja-build python3-pip`
 - `pip3 install -r tools/requirements-compliance.txt`
 
 For macOS the development dependencies can be installed as such:
@@ -148,9 +148,9 @@ The style is based on the LLVM style, but with 4 instead of 2 spaces indentation
 characters per line.
 
 To check if your code matches the expected style, the following commands are helpful:
- - `git clang-format-14 --diff`: Show what needs to be changed to match the expected code style
- - `git clang-format-14`: Apply all needed changes directly
- - `git clang-format-14 --commit main`: Fix code style for all changes since main
+ - `git clang-format-18 --diff`: Show what needs to be changed to match the expected code style
+ - `git clang-format-18`: Apply all needed changes directly
+ - `git clang-format-18 --commit main`: Fix code style for all changes since main
 
 If existing code gets reformatted, this must be done in a separate commit. Its commit id has to be added to the file
 `.git-blame-ignore-revs` and committed in yet another commit.

tools/ci/run_ci.sh

@@ -24,7 +24,7 @@ OPT_BRANCH_SOURCE=
 OPT_BRANCH_TARGET=main
 OPT_C_EXTENSIONS=""
 OPT_C_STANDARD=""
-OPT_CLANG_FORMAT="clang-format-14"
+OPT_CLANG_FORMAT="clang-format-18"
 OPT_SANITIZER=""
 OPT_SCAN_BUILD=""
 OPT_SONARQUBE=""
@@ -103,11 +103,12 @@ function run_clang_format() {
   # shellcheck disable=SC2064
   trap "{ rm -f -- '${patch_file}'; }" EXIT TERM INT
 
-  "git-${OPT_CLANG_FORMAT}" --diff "${OPT_BRANCH_TARGET}" 2>&1 |
+  (set +o pipefail; "git-${OPT_CLANG_FORMAT}" --diff "${OPT_BRANCH_TARGET}" 2>&1 |
     { grep -v \
       -e 'no modified files to format' \
       -e 'clang-format did not modify any files' || true;
     } > "${patch_file}"
+  )
 
   if [ -s "${patch_file}" ]; then
     cat "${patch_file}"