Skip to content

Blog

Guides to running clang-format and clang-tidy with cpp-linter.

  • in Guides
  • 7 min read

Run clang-tidy on pull requests with GitHub Actions

Running clang-tidy once on a laptop is easy. Running it on every pull request is where projects get stuck: clang-tidy needs the real compile flags or it reports missing headers, the first run on an existing code base produces thousands of findings nobody asked for, and the output ends up in a CI log that contributors do not open.

With the GitHub Actions job below, clang-tidy findings appear as review comments on the lines a pull request changed, and the check turns red when something is left unfixed.

  • in Guides
  • 6 min read

Set up a clang-format pre-commit hook for C and C++

Formatting comments are the cheapest part of a code review to get rid of. A pre-commit hook runs clang-format on the files in each commit, so badly formatted code rarely reaches a pull request, and CI stops failing for a missing space.

With the pre-commit framework, nobody on the team has to install LLVM, and everyone gets the same clang-format version.

  • in Guides
  • 4 min read

Moving to cpp-linter from other clang-format and clang-tidy actions

A common C++ workflow on GitHub has two lint jobs that grew up separately: a format check that fails the build, and a clang-tidy job that posts review comments. They pin different clang versions, they run on different triggers, and when one of them starts flaking nobody remembers why it was configured that way. Both jobs can be one cpp-linter-action step.

  • in Guides
  • 4 min read

One clang-format version everywhere: pre-commit, CI and your laptop

A pull request fails the format check. The author runs clang-format -i locally, pushes, and it fails again with a different diff. Nothing is wrong with the code. The laptop has clang-format 18, CI installed 21 from a package repository last week, and the reviewer's editor plugin ships 19.

Every major LLVM release changes clang-format's output in small ways: new style options, changed defaults, fixed bugs. clang-tidy is worse, because new checks appear and old ones move between categories. Pinning the project version of a linter wrapper does not help if the wrapper pulls whatever clang happens to be around.