wpiformat 2026.62

Linters and formatters for ensuring WPILib's source code conforms to its style guide

wpiformat

Provides linters and formatters for ensuring WPILib's C++, Java, and Python code conform to its style guide. WPILib uses a variant of the Google style guides.

Project Setup

To use wpiformat with a new project, copy .wpiformat-license from the examples folder into the project. If you're using C or C++, also create a new .clang-format file based on the desired C/C++ style.

Supported tasks

Name	File types	Description
BraceComment	C, C++	Ensures the trailing comment on the closing brace of extern and namespace declarations matches the declaration name.
CIdentList	C	Replaces empty identifier lists () with (void).
ClangFormat	C, C++	Runs clang-format.
ClangTidy	C, C++	Runs clang-tidy.
CMakeFormat	CMake	Runs gersemi.
EofNewline	all	Ensures that the file has zero EOF newlines if it's empty or one EOF newline.
GTestName	C, C++	Ensures Google Test test names follow the format TEST(ThingTest, Thing).
IncludeGuard	C header, C++ header	Makes include guards follow the Google style guide.
JavaClass	Java	Removes extra newlines after the line containing class.
Jni	C++ source	Formats JNI signatures according to javah's output.
LicenseUpdate	C, C++, Java	Updates the license header at the top of the file.
Lint	C++	Runs cpplint.py.
PyFormat	Python	Runs black.
UsingDeclaration	C++ header	Disallows using declarations in header global namespaces.
UsingNamespaceStd	C++	Warns against using namespace std;.
Whitespace	all	Removes trailing whitespace.

.wpiformat

This file contains groups of filename regular expressions.

groupName {
  regex_here
}

The regexes are matched using re.search(), so they don't have to match a file's whole path.

Empty config groups can be omitted. Directory separators must be /, not \. During processing, they will be replaced internally with an os.sep that is automatically escaped for regexes.

wpiformat checks the currently processed file's directory for a .wpiformat file first and traverses up the directory tree if one isn't found. This allows configs which are closer to the processed file to override a project's main config.

Specifying files to format

wpiformat has the following file extension associations: .h for C header files, .c for C source files, .hpp for C++ header files, .cpp for C++ source files, .py for Python files, and .java for Java files. Additional C and C++ files can be associated with the following groups:

• cHeaderFileInclude
• cppHeaderFileInclude
• cppSrcFileInclude

It's common to match just the file extension like so:

cppHeaderFileInclude {
  \.inc$
}

Ignoring files

There are two groups of regexes which prevent tasks (i.e., formatters and linters) from running on matching files:

• generatedFileExclude (generated files)
• modifiableFileExclude (modifiable files)

Generated files should not be modified by the user; if they are, wpiformat will emit warnings. No warnings are emitted for modifications to modifiable files. Exclusion groups take precedence over inclusion groups.

Files excluded from version control via .gitignore are skipped as modifiable.

The following file types are skipped as modifiable due to significant trailing whitespace:

• .jinja
• .patch

The following binary file types are skipped as modifiable:

• .dll
• .flac
• .gif
• .icns
• .ico
• .jar
• .jpeg
• .jpg
• .m4a
• .mp3
• .mp4
• .pdf
• .png
• .rknn
• .so
• .svg
• .tflite
• .ttf
• .wav
• .webp
• .woff2

License update exclusion

Filenames matching regexes in the group licenseUpdateExclude will be skipped by the license header update task.

Include guards

Valid include guard patterns have the following properties:

• Use capital letters
• Start with the repository name
• Include the path to the file and the filename itself
• Have directory separators and hyphens replaced with underscores
• Have a trailing underscore

The path to the file starts from the repository root by default. Other paths, such as include directories, can be specified in the includeGuardRoots group. If a path matches, that string will be truncated from the include guard pattern.

For example, given a file at allwpilib/src/main/native/include/wpiutil/support/ConcurrentQueue.h and an include path of src/main/native/include/, the resulting include guard would be ALLWPILIB_WPIUTIL_SUPPORT_CONCURRENTQUEUE_H_.

The repoRootNameOverride group allows one to override the repository name used in include guards. This is useful for giving subprojects within one repository different repository roots in their include guards. Only specify one name in this group because subsequent names will be ignored.

.wpiformat-license

This file contains the license header template. It should contain Copyright (c) followed by the company name and the string {year}. See the .wpiformat-license file in the examples directory.

wpiformat checks the currently processed file's directory for a .wpiformat-license file first and traverses up the directory tree if one isn't found. This allows templates which are closer to the processed file to override a project's main template.

License header semantics

The license header is always at the beginning of the file and ends after two newlines. If there isn't one, or it doesn't contain the required copyright contents, wpiformat inserts a new one containing the current year.

.wpiformat-license special variables

{year} is replaced with a year range from the earliest copyright year in the file to the current year. If the earliest year is the current year, only that year will be written.

// Copyright (c) {year} Company Name. All Rights Reserved.

{padding} is optional and represents an expanding space which pads the line to 80 columns. Multiple instances of {padding} on the same line share the padding equally.

/*{padding}Company Name{padding}*/

{filename} is optional and represents the current file's path relative to the Git repository root. Path separators are normalized to forward slashes on all platforms.