.. program:: stubgen
A stub file (see PEP 484) contains only type hints for the public interface of a module, with empty function bodies. Mypy can use a stub file instead of the real implementation to provide type information for the module. They are useful for third-party modules whose authors have not yet added type hints (and when no stubs are available in typeshed) and C extension modules (which mypy can't directly process).
Mypy includes the stubgen tool that can automatically generate
stub files (.pyi files) for Python modules and C extension modules.
For example, consider this source file:
from other_module import dynamic
BORDER_WIDTH = 15
class Window:
parent = dynamic()
def __init__(self, width, height):
self.width = width
self.height = height
def create_empty() -> Window:
return Window(0, 0)Stubgen can generate this stub file based on the above file:
from typing import Any
BORDER_WIDTH: int = ...
class Window:
parent: Any = ...
width: Any = ...
height: Any = ...
def __init__(self, width, height) -> None: ...
def create_empty() -> Window: ...Stubgen generates draft stubs. The auto-generated stub files often
require some manual updates, and most types will default to Any.
The stubs will be much more useful if you add more precise type annotations,
at least for the most commonly used functionality.
The rest of this section documents the command line interface of stubgen. Run :option:`stubgen --help` for a quick summary of options.
Note
The command-line flags may change between releases.
You can give stubgen paths of the source files for which you want to generate stubs:
$ stubgen foo.py bar.py
This generates stubs out/foo.pyi and out/bar.pyi. The default
output directory out can be overridden with :option:`-o DIR <-o>`.
You can also pass directories, and stubgen will recursively search
them for any .py files and generate stubs for all of them:
$ stubgen my_pkg_dir
Alternatively, you can give module or package names using the :option:`-m` or :option:`-p` options:
$ stubgen -m foo -m bar -p my_pkg_dir
Details of the options:
.. option:: -m MODULE, --module MODULE
Generate a stub file for the given module. This flag may be repeated
multiple times.
Stubgen *will not* recursively generate stubs for any submodules of
the provided module.
.. option:: -p PACKAGE, --package PACKAGE
Generate stubs for the given package. This flag maybe repeated
multiple times.
Stubgen *will* recursively generate stubs for all submodules of
the provided package. This flag is identical to :option:`--module` apart from
this behavior.
Note
You can't mix paths and :option:`-m`/:option:`-p` options in the same stubgen invocation.
Stubgen applies heuristics to avoid generating stubs for submodules that include tests or vendored third-party packages.
By default stubgen will try to import the target modules and packages. This allows stubgen to use runtime introspection to generate stubs for C extension modules and to improve the quality of the generated stubs. By default, stubgen will also use mypy to perform light-weight semantic analysis of any Python modules. Use the following flags to alter the default behavior:
.. option:: --no-import
Don't try to import modules. Instead only use mypy's normal search mechanism to find
sources. This does not support C extension modules. This flag also disables
runtime introspection functionality, which mypy uses to find the value of
``__all__``. As result the set of exported imported names in stubs may be
incomplete. This flag is generally only useful when importing a module causes
unwanted side effects, such as the running of tests. Stubgen tries to skip test
modules even without this option, but this does not always work.
.. option:: --no-analysis
Don't perform semantic analysis of source files. This may generate
worse stubs -- in particular, some module, class, and function aliases may
be represented as variables with the ``Any`` type. This is generally only
useful if semantic analysis causes a critical mypy error. Does not apply to
C extension modules. Incompatible with :option:`--inspet-mode`.
.. option:: --inspect-mode
Import and inspect modules instead of parsing source code. This is the default
behavior for c modules and pyc-only packages. The flag is useful to force
inspection for pure python modules that make use of dynamically generated
members that would otherwiswe be omitted when using the default behavior of
code parsing. Implies :option:`--no-analysis` as analysis requires source
code.
.. option:: --doc-dir PATH
Try to infer better signatures by parsing .rst documentation in ``PATH``.
This may result in better stubs, but currently it only works for C extension
modules.
.. option:: -h, --help
Show help message and exit.
.. option:: --ignore-errors
If an exception was raised during stub generation, continue to process any
remaining modules instead of immediately failing with an error.
.. option:: --include-private
Include definitions that are considered private in stubs (with names such
as ``_foo`` with single leading underscore and no trailing underscores).
.. option:: --export-less
Don't export all names imported from other modules within the same package.
Instead, only export imported names that are not referenced in the module
that contains the import.
.. option:: --search-path PATH
Specify module search directories, separated by colons (only used if
:option:`--no-import` is given).
.. option:: -o PATH, --output PATH
Change the output directory. By default the stubs are written in the
``./out`` directory. The output directory will be created if it doesn't
exist. Existing stubs in the output directory will be overwritten without
warning.
.. option:: -v, --verbose
Produce more verbose output.
.. option:: -q, --quiet
Produce less verbose output.