Having a common formatting convention throughout the code makes it more easy to follow for every developer.

Ideally, every source file in Gaudi should follow the same conventions, but with many contributors and no tool to enforce the conventions, the sources tend to get chaotic. So, in the context of GAUDI-1176, we added customized rules for the tool clang-format and helpers to use it.

For Python code we try to follow the rules described in PEP-8. The tool autopep8 can be used to fix the code, and if available it is used by the same helpers that we provide for clang-format.

To avoid that the rules are not followed, an automatic test is run on the merge requests to verify that they were applied, so developers and contributors are encouraged to apply the format rules to the files they modify.

Formatting the code

There are several ways to apply the formating rules via the clang-format tool. For example, the clang-format documentation page shows how to integrate its use in popular editors like Vim and Emacs, and IDEs like Qt Creator have plugins to call automatically clang-format. In this cases, to format Gaudi sources, one you specify the style file.

For the cases where integration with an editor or an IDE is not possible, or when the command line is preferred, we added a wrapper script in the build directory (apply-formatting) that simplifies the call to clang-format and autopep8. To use it you need to pass to it the path to the files you want to reformat (only C++ and Python files are taken into account). For example to apply the formatting rules to all files modified between two commits one can do something like:

cd gaudi_src_dir
gaudi_build_dir/apply-formatting $(git diff --name-only origin/master HEAD)

It's also possible to apply the formatting rules to all the files in the project with the special build target apply-formatting.