37 lines
2 KiB
Markdown
37 lines
2 KiB
Markdown
# Using clang-tidy on C++ Code
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[`clang-tidy`](https://clang.llvm.org/extra/clang-tidy/) is a tool to
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automatically check C/C++/Objective-C code for style violations, programming
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errors, and best practices.
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Electron's `clang-tidy` integration is provided as a linter script which can
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be run with `npm run lint:clang-tidy`. While `clang-tidy` checks your on-disk
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files, you need to have built Electron so that it knows which compiler flags
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were used. There is one required option for the script `--output-dir`, which
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tells the script which build directory to pull the compilation information
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from. A typical usage would be:
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`npm run lint:clang-tiy --out-dir ../out/Testing`
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With no filenames provided, all C/C++/Objective-C files will be checked.
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You can provide a list of files to be checked by passing the filenames after
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the options:
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`npm run lint:clang-tiy --out-dir ../out/Testing shell/browser/api/electron_api_app.cc`
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While `clang-tidy` has a
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[long list](https://clang.llvm.org/extra/clang-tidy/checks/list.html)
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of possible checks, in Electron only a few are enabled by default. At the
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moment Electron doesn't have a `.clang-tidy` config, so `clang-tidy` will
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find the one from Chromium at `src/.clang-tidy` and use the checks which
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Chromium has enabled. You can change which checks are run by using the
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`--checks=` option. This is passed straight through to `clang-tidy`, so see
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its documentation for full details. Wildcards can be used, and checks can
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be disabled by prefixing a `-`. By default any checks listed are added to
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those in `.clang-tidy`, so if you'd like to limit the checks to specific
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ones you should first exclude all checks then add back what you want, like
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`--checks=-*,performance*`.
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Running `clang-tidy` is rather slow - internally it compiles each file and
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then runs the checks so it will always be some factor slower than compilation.
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While you can use parallel runs to speed it up using the `--jobs|-j` option,
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`clang-tidy` also uses a lot of memory during its checks, so it can easily
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run into out-of-memory errors. As such the default number of jobs is one.
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