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Clang-Tidy

Clang-Tidy Setup​

The Mozilla VPN Client project utilizes Clang-Tidy to enforce code quality standards. Clang-Tidy is provided with our conda-environment.

Prerequisites​

In general, the default conda-env should be working out of the box, in case its not:

To run clang-tidy you need to generate a compile-commands.json,

  1. Set the Generator to Ninja or Makefiles
  2. Use Clang as the compiler
  3. Enable compilation-databases (-DCMAKE_EXPORT_COMPILE_COMMANDS=ON)

Running Clang-Tidy​

You can build a clang-tidy report by calling:

    # For all files
    cmake --build <build_dir> --target clang_tidy_report
    # Just a subtarget
    cmake --build <build_dir> --target ${target}_clang_tidy_report

This will report errors and suggestions to the console, as well as build a yaml report for each target in <build_dir>/clang-tidy/<target>-report.yaml.

Fixing Issues:​

Some checks can be fixed automatically. You can use clang-apply-replacements to auto apply any suggestion.

    # Generate a report in <build_dir>/clang-tidy/
    cmake --build <build_dir> --target clang_tidy_report
    # Apply all suggestions: 
    clang-apply-replacements <build_dir>/clang-tidy/

Help​

Error: error: 'some.h' file not found [clang-diagnostic-error]​

Make sure that either all targets (including tests) are built or try configuring with -DBUILD_TESTS=OFF.

This might happen clang-tidy reads the compilation database for each file i.e a.cpp, if there are 2 object files built from a.cpp i.e:

add_library(lib_a a.cpp)
add_library(lib_b a.cpp)

it will pick one, so either make sure only one lib is configured, all possible dependencies for a.cpp are attached to the lint target or create a smaller target.

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