This section provides a list of tools that some have found useful for ensuring their code abides by Drake’s Code Style Guide. The list is by no means comprehensive. If your favorite tools or methodologies are not listed, we would be delighted to learn about them. Please document your trick and submit a pull request!

Automated style checks

Code style tests are run by default during bazel test and the results are cached so that only edited files are re-checked. In other words, no special action is required by a developer.

However, you may still invoke code style checks directly if desired, as follows:

cd /path/to/drake
bazel test --config lint //...         # Only run style checks; don't build or test anything else.
bazel test --config lint //common/...  # Check common/ and its child subdirectories.

User manuals for the style-checking tools are as follows:

C/C++: See the cpplint USAGE string at https://github.com/google/styleguide/blob/gh-pages/cpplint/cpplint.py.
- In particular, note the // NOLINT(foo/bar) syntax to disable a warning.
Python: See the pycodestyle manual at http://pycodestyle.readthedocs.io/en/latest/intro.html.
- The syntax # noqa can be used to quiet the warning about an overly-long line.
Bazel: Uses both pycodestyle like Python, and also the buildifier tool as described in Updating BUILD files.

Manual style fixups

C/C++: Clang-Format

The Mandatory platform-specific instructions install Drake’s required version of clang-format, depending on the platform (macOS or Ubuntu).

To run clang-format:

clang-format-15 -i -style=file [file name]

Using clang-format will modify the entire file that is specified. As an alternative, you can use git clang-format on Ubuntu to change only the portions of a file that you have modified. To run git clang-format:

# For development on Ubuntu: format a file that has been staged in git
git clang-format-15 --binary=/usr/bin/clang-format-15 -- [file name]

# For development on Ubuntu: format a file that has been modified but not staged
git clang-format-15 --binary=/usr/bin/clang-format-15 -f -- [file name]

On macOS, the command to use is /opt/homebrew/opt/llvm@15/bin/clang-format. Note in particular that 15 is part of the directory name, not a suffix on the program name.

IDE integration

Most IDEs can run clang-format automatically. We have some tips for specific IDEs: