flycheck-clang-tidy

Flycheck syntax checker using clang-tidy

This library provides a flycheck checker for C/C++ source code using clang-tidy.

Installation

You'll need Emacs 24 for flycheck, so the recommended way to get flycheck-clang-tidy is as a package from the MELPA repository.

Alternatively you have to ensure flycheck is installed, then download this code and add the directory to your Emacs load-path.

Then, in your init.el:

(eval-after-load 'flycheck
  '(add-hook 'flycheck-mode-hook #'flycheck-clang-tidy-setup))

Or, if you use use-package:

(use-package flycheck-clang-tidy
  :after flycheck
  :hook
  (flycheck-mode . flycheck-clang-tidy-setup)
  )

Make sure that the clang-tidy binary is present on Emacs' exec-path, or customize flycheck-clang-tidy-executable to point to the clang-tidy binary.

Usage

When flycheck is enabled (e.g. with global-flycheck-mode), c-mode and c++-mode buffers will be automatically checked using this checker.

To have clang-tidy work correctly, you usally require a compile command database as described in clang-tidy --help. For example using CMake a file named compile_commands.json can be created using -DCMAKE_EXPORT_COMPILE_COMMANDS=ON. flycheck-clang-tidy then looks for this file via variable flycheck-clang-tidy-build-path which defaults to build.

You can pass additional options to clang-tidy using the variable flycheck-clang-tidy-extra-options.

This checker includes an error explainer. Invoking flycheck-explain-error-at-point will search clang.llvm.org for the documentation of the clang-tidy check under point and render the result HTML in a Help buffer. This requires that Emacs is compiled with XML support.

Known problems

When clang-tidy is run via docker, the config file is unquoted before it reaches the process which means that it can't be parsed. The recommended workaround is to add an advice around flycheck-clang-tidy-get-config and quote the config file a second time.

(advice-add 'flycheck-clang-tidy-get-config :around
            (lambda (original-function)
              (shell-quote-argument (funcall original-function))))

Other solutions

If you use lsp-mode with clangd 9.0 or above, you can use the embedded clang-tidy by adding --clang-tidy to lsp-clients-clangd-args.