mypy - Man Page
manual page for mypy 1.13.0-dev
Examples (TL;DR)
- Type check a specific file:
mypy path/to/file.py
- Type check a specific [m]odule:
mypy -m module_name
- Type check a specific [p]ackage:
mypy -p package_name
- Type check a string of code:
mypy -c "code"
- Ignore missing imports:
mypy --ignore-missing-imports path/to/file_or_directory
- Show detailed error messages:
mypy --show-traceback path/to/file_or_directory
- Specify a custom configuration file:
mypy --config-file path/to/config_file
- Display [h]elp:
mypy -h
Description
usage: mypy [-h] [-v] [-V] [more options; see below]
[-m MODULE] [-p PACKAGE] [-c PROGRAM_TEXT] [files ...]
Mypy is a program that will type check your Python code.
Pass in any files or folders you want to type check. Mypy will recursively traverse any provided folders to find .py files:
$ mypy my_program.py my_src_folder
For more information on getting started, see:
- https://mypy.readthedocs.io/en/stable/getting_started.html
For more details on both running mypy and using the flags below, see:
- https://mypy.readthedocs.io/en/stable/running_mypy.html - https://mypy.readthedocs.io/en/stable/command_line.html
You can also use a config file to configure mypy instead of using command line flags. For more details, see:
- https://mypy.readthedocs.io/en/stable/config_file.html
options
- --enable-incomplete-feature {InlineTypedDict,PreciseTupleTypes}
Enable support of incomplete/experimental features for early preview
Optional arguments
- -h, --help
Show this help message and exit
- -v, --verbose
More verbose messages
- -V, --version
Show program's version number and exit
- -O, --output FORMAT
Set a custom output format
Config file
Use a config file instead of command line arguments. This is useful if you are using many flags or want to set different options per each module.
- --config-file CONFIG_FILE
Configuration file, must have a [mypy] section (defaults to mypy.ini, .mypy.ini, pyproject.toml, setup.cfg, ~/.config/mypy/config, ~/.mypy.ini)
- --warn-unused-configs
Warn about unused '[mypy-<pattern>]' or '[[tool.mypy.overrides]]' config sections (inverse: --no-warn-unused-configs)
Import discovery
Configure how imports are discovered and followed.
- --no-namespace-packages
Disable support for namespace packages (PEP 420, __init__.py-less) (inverse: --namespace-packages)
- --ignore-missing-imports
Silently ignore imports of missing modules
- --follow-imports {normal,silent,skip,error}
How to treat imports (default normal)
- --python-executable EXECUTABLE
Python executable used for finding PEP 561 compliant installed packages and stubs
- --no-site-packages
Do not search for installed PEP 561 compliant packages
- --no-silence-site-packages
Do not silence errors in PEP 561 compliant installed packages
- --junit-format {global,per_file}
If --junit-xml is set, specifies format. global: single test with all errors; per_file: one test entry per file with failures
Platform configuration
Type check code assuming it will be run under certain runtime conditions. By default, mypy assumes your code will be run using the same operating system and Python version you are using to run mypy itself.
- --python-version x.y
Type check code assuming it will be running on Python x.y
- --platform PLATFORM
Type check special-cased code for the given OS platform (defaults to sys.platform)
- --always-true NAME
Additional variable to be considered True (may be repeated)
- --always-false NAME
Additional variable to be considered False (may be repeated)
Disallow dynamic typing
Disallow the use of the dynamic 'Any' type under certain conditions.
- --disallow-any-unimported
Disallow Any types resulting from unfollowed imports
- --disallow-any-expr
Disallow all expressions that have type Any
- --disallow-any-decorated
Disallow functions that have Any in their signature after decorator transformation
- --disallow-any-explicit
Disallow explicit Any in type positions
- --disallow-any-generics
Disallow usage of generic types that do not specify explicit type parameters (inverse: --allow-any-generics)
- --disallow-subclassing-any
Disallow subclassing values of type 'Any' when defining classes (inverse: --allow-subclassingany)
Untyped definitions and calls
Configure how untyped definitions and calls are handled. Note: by default, mypy ignores any untyped function definitions and assumes any calls to such functions have a return type of 'Any'.
- --disallow-untyped-calls
Disallow calling functions without type annotations from functions with type annotations (inverse: --allow-untyped-calls)
- --untyped-calls-exclude MODULE
Disable --disallow-untyped-calls for functions/methods coming from specific package, module, or class
- --disallow-untyped-defs
Disallow defining functions without type annotations or with incomplete type annotations (inverse: --allow-untyped-defs)
- --disallow-incomplete-defs
Disallow defining functions with incomplete type annotations (while still allowing entirely unannotated definitions) (inverse: --allowincomplete-defs)
- --check-untyped-defs
Type check the interior of functions without type annotations (inverse: --no-check-untyped-defs)
- --disallow-untyped-decorators
Disallow decorating typed functions with untyped decorators (inverse: --allow-untyped-decorators)
None and Optional handling
Adjust how values of type 'None' are handled. For more context on how mypy handles values of type 'None', see: https://mypy.readthedocs.io/en/stable/kinds_of_types.html#no-strictoptional
- --implicit-optional
Assume arguments with default values of None are Optional (inverse: --no-implicit-optional)
- --no-strict-optional
Disable strict Optional checks (inverse: --strictoptional)
Configuring warnings
Detect code that is sound but redundant or problematic.
- --warn-redundant-casts
Warn about casting an expression to its inferred type (inverse: --no-warn-redundant-casts)
- --warn-unused-ignores
Warn about unneeded '# type: ignore' comments (inverse: --no-warn-unused-ignores)
- --no-warn-no-return
Do not warn about functions that end without returning (inverse: --warn-no-return)
- --warn-return-any
Warn about returning values of type Any from nonAny typed functions (inverse: --no-warn-returnany)
- --warn-unreachable
Warn about statements or expressions inferred to be unreachable (inverse: --no-warn-unreachable)
Miscellaneous strictness flags
- --allow-untyped-globals
Suppress toplevel errors caused by missing annotations (inverse: --disallow-untyped-globals)
- --allow-redefinition
Allow unconditional variable redefinition with a new type (inverse: --disallow-redefinition)
- --no-implicit-reexport
Treat imports as private unless aliased (inverse: --implicit-reexport)
- --strict-equality
Prohibit equality, identity, and container checks for non-overlapping types (inverse: --no-strictequality)
- --extra-checks
Enable additional checks that are technically correct but may be impractical in real code. For example, this prohibits partial overlap in TypedDict updates, and makes arguments prepended via Concatenate positional-only (inverse: --noextra-checks)
- --strict
Strict mode; enables the following flags: --warnunused-configs, --disallow-any-generics, --disallow-subclassing-any, --disallow-untypedcalls, --disallow-untyped-defs, --disallowincomplete-defs, --check-untyped-defs, --disallowuntyped-decorators, --warn-redundant-casts, --warn-unused-ignores, --warn-return-any, --noimplicit-reexport, --strict-equality, --extrachecks
- --disable-error-code NAME
Disable a specific error code
- --enable-error-code NAME
Enable a specific error code
Configuring error messages
Adjust the amount of detail shown in error messages.
- --show-error-context
Precede errors with "note:" messages explaining context (inverse: --hide-error-context)
- --show-column-numbers
Show column numbers in error messages (inverse: --hide-column-numbers)
- --show-error-end
Show end line/end column numbers in error messages. This implies --show-column-numbers (inverse: --hide-error-end)
- --hide-error-codes
Hide error codes in error messages (inverse: --show-error-codes)
- --show-error-code-links
Show links to error code documentation (inverse: --hide-error-code-links)
- --pretty
Use visually nicer output in error messages: Use soft word wrap, show source code snippets, and show error location markers (inverse: --no-pretty)
- --no-color-output
Do not colorize error messages (inverse: --coloroutput)
- --no-error-summary
Do not show error stats summary (inverse: --errorsummary)
- --show-absolute-path
Show absolute paths to files (inverse: --hideabsolute-path)
Incremental mode
Adjust how mypy incrementally type checks and caches modules. Mypy caches type information about modules into a cache to let you speed up future invocations of mypy. Also see mypy's daemon mode: mypy.readthedocs.io/en/stable/mypy_daemon.html#mypy-daemon
- --no-incremental
Disable module cache (inverse: --incremental)
- --cache-dir DIR
Store module cache info in the given folder in incremental mode (defaults to '.mypy_cache')
- --sqlite-cache
Use a sqlite database to store the cache (inverse: --no-sqlite-cache)
- --cache-fine-grained
Include fine-grained dependency information in the cache for the mypy daemon
- --skip-version-check
Allow using cache written by older mypy version
- --skip-cache-mtime-checks
Skip cache internal consistency checks based on mtime
Advanced options
Debug and customize mypy internals.
- --pdb
Invoke pdb on fatal error
- --show-traceback, --tb
Show traceback on fatal error
- --raise-exceptions
Raise exception on fatal error
- --custom-typing-module MODULE
Use a custom typing module
- --old-type-inference
Disable new experimental type inference algorithm
- --custom-typeshed-dir DIR
Use the custom typeshed in DIR
- --warn-incomplete-stub
Warn if missing type annotation in typeshed, only relevant with --disallow-untyped-defs or --disallow-incomplete-defs enabled (inverse: --nowarn-incomplete-stub)
- --shadow-file SOURCE_FILE SHADOW_FILE
When encountering SOURCE_FILE, read and type check the contents of SHADOW_FILE instead.
Report generation
Generate a report in the specified format.
--any-exprs-report DIR
--cobertura-xml-report DIR
--html-report DIR
--linecount-report DIR
--linecoverage-report DIR
--lineprecision-report DIR
--txt-report DIR
--xml-report DIR
--xslt-html-report DIR
--xslt-txt-report DIR
Miscellaneous
- --junit-xml JUNIT_XML
Write junit.xml to the given file
- --find-occurrences CLASS.MEMBER
Print out all usages of a class member (experimental)
- --scripts-are-modules
Script x becomes module x instead of __main__
- --install-types
Install detected missing library stub packages using pip (inverse: --no-install-types)
- --non-interactive
Install stubs without asking for confirmation and hide errors, with --install-types (inverse: --interactive)
Running code
Specify the code you want to type check. For more details, see mypy.readthedocs.io/en/stable/running_mypy.html#running-mypy
- --explicit-package-bases
Use current directory and MYPYPATH to determine module names of files passed (inverse: --noexplicit-package-bases)
- --exclude PATTERN
Regular expression to match file names, directory names or paths which mypy should ignore while recursively discovering files to check, e.g. --exclude '/setup\.py$'. May be specified more than once, eg. --exclude a --exclude b
- -m, --module MODULE
Type-check module; can repeat for more modules
- -p, --package PACKAGE
Type-check package recursively; can be repeated
- -c, --command PROGRAM_TEXT
Type-check program passed in as string
- files
Type-check given files or directories
Environment variables
Define MYPYPATH for additional module search path entries. Define MYPY_CACHE_DIR to override configuration cache_dir path.