A quality checker for Python wheels

GitHub | PyPI | Issues

Getting the right files into your wheel is tricky, and sometimes we mess up and publish a wheel containing __pycache__ directories or tests/ . Do we have to manually check the contents of every wheel we build before uploading it to PyPI? How about letting this program check for you? Just run check-wheel-contents on your wheel, and it'll fail and notify you if any of several common errors & mistakes are detected. The errors are described below, along with common causes and corresponding fixes.

Installation

check-wheel-contents requires Python 3.6 or higher. Just use pip for Python 3 (You have pip, right?) to install check-wheel-contents and its dependencies:

python3 -m pip install check-wheel-contents

Usage

check-wheel-contents [<options>] <wheel or directory> ...

check-wheel-contents takes zero or more paths as arguments, each pointing to either a wheel to analyze or a directory that will be traversed for wheels to analyze. If a given wheel fails any checks, a message will be printed for each check along with (if applicable) a list of filepaths in the wheel causing the check to fail, and the command will exit with a nonzero status. If a wheel passes all checks, the program will print {path_to_wheel}: OK .

Options

• -c <file> , --config <file> — Read configuration from the given file; see below for more information
• --no-config — Disable reading from the configuration file
• -h , --help — Display a usage message and exit
• -V , --version — Display the program version and exit

The remaining options can be given either on the command line or in the configuration file; see "Configuration Options" for more information.

Configuration

Configuration File

If a configuration file is specified on the command line with the --config option, check-wheel-contents reads its configuration from the given file. Files with a .toml extension are parsed as TOML files, and the configuration is read from the tool.check-wheel-contents table. All other files are parsed as INI files, and their configuration is read from the [check-wheel-contents] section (unless the file is named setup.cfg , in which case the section [tool:check-wheel-contents] is used instead).

If no configuration file is specified on the command line, the program begins searching for a file named pyproject.toml , tox.ini , setup.cfg , check-wheel-contents.cfg , or .check-wheel-contents.cfg , starting in the current directory and going up. The files are read using the same rules as for the --config option, and the first file in the list that contains the appropriate section is used. Searching stops once a directory containing any of the named files is found, even if none of them contain the relevant section.

Configuration Options

The following options may be set either on the command line or in the configuration file. Settings given on the command line override those in the configuration file. Unknown keys in configuration files are ignored.

--select <checks> / select = <checks>

Select/enable only the given checks. <checks> is a comma-separated list of check IDs and/or check ID prefixes (to select all checks beginning with the given prefixes).

In a TOML file, <checks> may alternatively be given as a list of strings.

By default, all checks are selected (though some checks are no-ops when certain other options are/aren't given).

--ignore <checks> / ignore = <checks>

Ignore/skip the given checks. <checks> is a comma-separated list of check IDs and/or check ID prefixes (to ignore all checks beginning with the given prefixes).

In a TOML file, <checks> may alternatively be given as a list of strings.

By default, no checks are ignored.

--toplevel <names> / toplevel = <names>

Tell check-wheel-contents to check that the toplevel library entries of the wheel equal the set of names in the comma-separated list <names> ; e.g., --toplevel foo.py,bar/ checks that foo.py , bar , and nothing else is at the top level of your wheel. Trailing slashes on directory names are optional.

In a TOML file, <names> may alternatively be given as a list of strings.

This option disables check W009 and enables checks W201 and W202.

--package <path> / package = <paths>

Tell check-wheel-contents to check that the wheel's library sections contain the file tree rooted at <path> .

Paths given on the command line are resolved relative to the current working directory. Paths given in a configuration file are resolved relative to the directory containing the configuration file.

On the command line, multiple paths can be specified by supplying --package multiple times. In a configuration file, multiple paths can be specified by setting package to a comma-separated list of paths. In a TOML file, <paths> may alternatively be given as a list of strings.

This option disables check W009 and enables checks W101 and W102.

--src-dir <path> / src_dir = <paths>

The same as --package , except that only the contents of <path> (which must be a directory) and not <path> itself are checked against the wheel's contents.

--package-omit <patterns> / package_omit = <patterns>

Ignore files & directories inside --package or --src-dir arguments that match any of the glob patterns in the comma-separated list <patterns> . Ignored files will not be looked for in wheels for check W101, and if any of them do show up in a wheel, it will cause check W102 to fail.

In a TOML file, <patterns> may alternatively be given as a list of strings.

The default set of ignored patterns is .*, CVS, RCS, *.pyc, *.pyo, *.egg-info .

Checks

Note: Unless otherwise stated, the common causes and their fixes listed here are specific to projects developed using setuptools. Users of other tools like flit and poetry will have to consult those projects' documentation in order to resolve failed checks.

Note: When rebuilding a wheel with setuptools, it is a good idea to delete the build/ directory first. (This can be done in a single command with python setup.py clean --all bdist_wheel .) Not doing this can cause various checks to continue to fail or new ones to start failing.

W001 — Wheel contains .pyc/.pyo files

This check fails if there are any files in the wheel with a .pyc or .pyo extension. Such files are compiled Python bytecode files, and they do not belong in wheels, because (a) they are platform-specific and thus useless to many of your users, and (b) pip generates .pyc files for the .py files in your wheel automatically.

Common causes:

• You have include_package_data set to True , your MANIFEST.in contains graft packagename or recursive-include packagename * , and the line global-exclude *.py[co] or similar is either missing from the MANIFEST.in or else in the wrong location.

  Solution: Ensure that global-exclude *.py[co] appears in your MANIFEST.in file after all include , recursive-include , global-include , and graft commands.

• You have [install]optimize = 1 set in setup.cfg (or, equivalently, options={"install": {"optimize": "1"}} set in setup.py ).

  Solution: Remove this setting. It's only useful when using setup.py install anyway, which is deprecated.

W002 — Wheel contains duplicate files

This check fails if any two files in the wheel have the same contents. Common file contents, such as files that are empty or just contain the line " # -*- coding: utf-8 -*- ", are excluded from this check.

Common causes:

• (Build tool agnostic) You copied a file or directory when you actually meant to rename it.

  Solution: Delete the original copy of the file or directory.

• You built a wheel, renamed a file or directory, and then built a wheel again without first deleting the build/ directory.

  Solution: Delete the build/ directory and build the wheel again.

W003 — Wheel contains non-module at library toplevel

This check fails if there are any files at the root of the purelib or platlib section of the wheel that are not Python modules or .pth files. Non-modules belong elsewhere in a wheel:

• Licenses and similar notices should be stored in the wheel's *.dist-info directory using wheel 's license_files option.
• Package data/resource files belong inside a package directory so that they can be located with pkg_resources or importlib-resources .
• A project's README should already be used as the project's long_description , in which case the text of the README is already included in the wheel inside the *.dist-info/METADATA file. There should thus be no need to store the README in the wheel's library sections.

W004 — Module is not located at importable path

This check fails if there are any Python modules in the purelib or platlib section of the wheel that cannot be imported due to one or more of their path components being invalid Python identifiers.

Common causes:

• (Build tool agnostic) You gave a package directory or module a name containing a hyphen or other character not allowed in Python identifiers.

  Solution: Rename the offending directory or module to remove the offending character, most likely by changing it to an underscore.

• (Build tool agnostic) You gave a package directory or module the name of a Python keyword.

  Solution: Rename the offending directory or module.

W005 — Wheel contains common toplevel name in library

This check fails if there are any files or directories named .eggs , .nox , .tox , .venv , build , data , dist , doc , docs , example , examples , src , test , tests , or venv located at the root of the purelib or platlib section of the wheel. These names are conventionally used for directories that don't belong in wheels (aside from src , whose contents belong in wheels but itself does not belong in a wheel). Projects should only use toplevel names that resemble the project name; using common names will cause different projects' files to overwrite each other on installation.

Common causes:

• For src : You failed to set up your src/ layout correctly. src should not contain an __init__.py file, where='src' needs to be passed to setuptools.find_packages() in setup.py , and package_dir={"": "src"} needs to be passed to setup() in setup.py .

• For directories other than src : The directory contains an __init__.py file, and the directory is not listed in the exclude argument to setuptools.find_packages() in setup.py .

  Solution: Include 'DIRNAME' and 'DIRNAME.*' in the list passed to the exclude argument of find_packages() .

• For directories other than src : The directory is listed in the exclude argument to find_packages() , but 'DIRNAME.*' is not, and a subdirectory of the directory contains an __init__.py file.

  Solution: Include 'DIRNAME.*' in the list passed to the exclude argument of find_packages() .

• You actually want to include your tests or examples in your wheel.

  Solution: Move the tests or whatever to inside your main package directory (e.g., move tests/ to somepackage/tests/ ) so that they won't collide with other projects' files on installation.

W006 — __init__.py at top level of library

This check fails if there is a file named __init__.py at the root of the purelib or platlib section of the wheel. __init__.py files only belong inside package directories, not at the root of an installation.

Common causes:

• You failed to set up your src/ layout correctly. src should not contain an __init__.py file, where='src' needs to be passed to setuptools.find_packages() in setup.py , and package_dir={"": "src"} needs to be passed to setup() in setup.py .

• You created an __init__.py file at the root of your project and set packages='.' in setup.py .

  Solution: Configure your project's packages correctly. For single-file modules, pass a list of their names (without the .py extension) to the py_modules argument to setup() . For package modules (directories), pass a list of their names and the dotted names of their descendant subpackages (possibly obtained by calling setuptools.find_packages() ) to packages .

W007 — Wheel library is empty

This check fails if the wheel contains no files in either its purelib or platlib section.

Common causes:

• Your project consists of a single-file .py module, but you declared it to setup() in setup.py using the packages keyword.

  Solution: Single-file modules must be declared to setup() using the py_modules keyword. Pass it a list of the names of your single-file modules without the .py extension.

• You are using setuptools.find_packages() to list your packages for setup() , but your package does not contain an __init__.py file.

  Solution: Create an __init__.py file in your package. If this is not an option because you are building a namespace package, use setuptools.find_namespace_packages() instead of find_packages() . Be sure to set the arguments appropriately so that the function only finds your main package; see the documentation for further information .

• You're deliberately creating a wheel that only contains scripts, headers, or other data files.

  Solution: Ignore this check.

W008 — Wheel is empty

This check fails if the wheel contains no files other than the *.dist-info metadata directory. It is a stronger check than W007, intended for users who are creating wheels that only contain scripts, headers, and other data files and thus need to ignore W007.

Common causes:

• Same causes as for W007

• You're deliberately creating an empty wheel whose only function is to cause a set of dependencies to be installed.

  Solution: Ignore this check.

W009 — Wheel contains multiple toplevel library entries

This check fails if the wheel's purelib and platlib sections contain more than one toplevel entry between them, excluding .pth files and files & directories that begin with an underscore. This is generally a sign that something has gone wrong in packaging your project, as very few projects want to distribute code with multiple top-level modules or packages.

This check is disabled if the --toplevel , --package , or --src-dir option is given either on the command line or in the configuration file.

Common causes:

• You built a wheel, renamed a toplevel file or directory, and then built a wheel again without first deleting the build/ directory.

  Solution: Delete the build/ directory and build the wheel again.

• You are using setuptools.find_packages() in your setup.py , your project contains multiple directories with __init__.py files, and one or more of these directories (other than your main package) is not listed in the exclude argument to find_packages() .

  Solution: Pass a list of all __init__.py -having directories in your project other than your main package to the exclude argument of find_packages() . For proper exclusion, each directory DIRNAME should correspond to two elements of this list, 'DIRNAME' and 'DIRNAME.*' , in order to ensure that the directory and all of its subdirectories are excluded.

• You are deliberately creating a wheel with multiple top-level Python modules or packages.

  Solution: Use the --toplevel option to let check-wheel-contents know what toplevel entries to expect.

W010 — Toplevel library directory contains no Python modules

This check fails if a directory tree rooted at the root of the purelib or platlib section of the wheel contains no Python modules. *-stubs directories are excluded from this check.

W101 — Wheel library is missing files in package tree

This check is only enabled if the --package or --src-dir option is set. This check fails if a path in a tree rooted at an argument to --package or inside an argument to --src-dir does not appear in the wheel's purelib or platlib section. Empty directories and local files & directories that match any of the patterns specified with --package-omit or its default value are excluded from this check.

Note that this check only checks file paths, i.e., names of files & directories. File contents are not examined.

For example, given the below local tree:

/usr/src/project/
├── foo/
│   ├── .gitignore
│   ├── __init__.py
│   └── foo.py
└── src/
    ├── bar/
    │   ├── __init__.py
    │   ├── bar.py
    │   ├── empty/
    │   └── quux/
    │       └── data.dat
    └── bar.egg-info/
        └── PKG-INFO

If the options --package /usr/src/project/foo and --src-dir /usr/src/project/src are supplied and --package-omit is left at its default value, then check-wheel-contents will look for the following paths in the wheel, and the check will fail if any of them do not appear in either the purelib or platlib section:

foo/__init__.py
foo/foo.py
bar/__init__.py
bar/bar.py
bar/quux/data.dat

Note that foo/.gitignore and src/bar.egg-info are omitted from this check (and if they do appear in the wheel, it will cause check W102 to fail). Empty directories are ignored altogether.

Common causes:

• For Python files: You failed to pass all of your project's packages & subpackages to setup() 's packages argument. If you are using setuptools.find_packages() , all of your packages & subpackages need to contain __init__.py files.
• For non-Python files: You failed to declare your project's package data appropriately. See the setuptools documentation for information on how to do this < https://setuptools.readthedocs.io/en/latest/setuptools.html#including-data-files>_ .

W102 — Wheel library contains files not in package tree

This check is only enabled if the --package or --src-dir option is set. This check fails if the purelib or platlib section of the wheel contains any files at paths that do not exist in any of the file trees specified with --package or --src-dir .

Note that this check only checks file paths, i.e., names of files & directories. File contents are not examined.

For example, given the local tree and options shown in the example under W101, this check will fail if the wheel contains any files in its purelib or platlib section other than the following:

foo/__init__.py
foo/foo.py
bar/__init__.py
bar/bar.py
bar/quux/data.dat

Note that files & directories that match any of the patterns specified with --package-omit or its default value are ignored in local trees, and so any entries with those names in the wheel will cause this check to fail. Empty directories are ignored altogether.

Common causes: See common causes of W009

W201 — Wheel library is missing specified toplevel entry

This check is only enabled if the --toplevel option is set. This check fails if one or more of the names given in the --toplevel option does not appear at the root of the purelib or platlib section of the wheel.

Common causes: See common causes of W007

W202 — Wheel library has undeclared toplevel entry

This check is only enabled if the --toplevel option is set. This check fails if there is a file or directory at the root of the purelib or platlib section of the wheel that is not listed in the --toplevel option. *.pth files are ignored for the purposes of this check.

Common causes: See common causes of W009