What is clang-tidy?

clang-tidy is a static analysis tool using the LLVM / clang tooling. It can detect a number of issues with C++ code, like common readability problems, performance or memory safety issues.

The ACTS CI automatically runs clang-tidy on all compilation units to detect as many problems as possible, and requires developers to resolve them. It is configured with a file .clang-tidy located in the repository root. Many editors / IDEs support clang-tidy and will automatically pick up this configuration file.

By default, only a limited number of checks are configured in this file, but this list might change in the future. If you experience CI failures that are associated with clang-tidy, you can drill down into the CI job outputs to get a report on the issues it detected. The report should give you an error / warning code, e.g. readability-braces-around-statements. The LLVM documentation has details on all possible error codes, in this particular example you would find it here. This page will tell you that clang-tidy wants you to replace

if (condition)


if (condition) {

Some error codes are less obvious, or not this trivial to fix. When in doubt, @mention the ACTS maintainers on your pull request.