Command-line configuration

Configure Mypy using command-line flags and options for type checking control

Mypy can be configured using command-line flags in addition to configuration files. Command-line flags have higher precedence than configuration file options (except for inline configuration).

Basic usage

mypy program.py
mypy package/
mypy -m mymodule
mypy -p mypackage

Specifying code to check

files · positional arguments

Files, directories, modules, or packages to type check.

mypy file1.py file2.py
mypy src/

-m MODULE · string

Type check a module by name.

mypy -m myapp.main

-p PACKAGE · string

Type check a package and all its submodules.

mypy -p mypackage

-c PROGRAM_TEXT · string

Type check a program passed as a string.

mypy -c "print('Hello, typed world!')"

Configuration file

--config-file CONFIG_FILE · string

Specify a configuration file to use.

mypy --config-file mypy-strict.ini src/

This flag has the highest precedence and must point to a valid configuration file.

--warn-unused-configs · boolean

Warn about unused [mypy-<pattern>] config file sections.

mypy --warn-unused-configs src/

Python version and platform

--python-version VERSION · string · default: "Current Python version"

Specify the Python version to target. Format: MAJOR.MINOR.

mypy --python-version 3.10 src/

Use this to check code compatibility with different Python versions.

--platform PLATFORM · string · default: "Current platform"

Specify the platform to check against (e.g., linux, darwin, win32).

mypy --platform win32 src/

--always-true NAME · string

Variables to treat as compile-time constants that are always true.

mypy --always-true DEBUG src/

--always-false NAME · string

Variables to treat as compile-time constants that are always false.

mypy --always-false TYPING_ONLY src/

Import discovery

--ignore-missing-imports · boolean

Suppress error messages about imports that cannot be resolved.

mypy --ignore-missing-imports src/

This is a blunt instrument. Consider using per-module configuration instead.

--follow-imports {normal,silent,skip,error} · choice · default: "normal"

How to handle imports:

• normal: Follow imports and type check them
• silent: Follow imports but suppress errors
• skip: Don’t follow imports (treat as Any)
• error: Treat imports as errors

mypy --follow-imports skip src/

--python-executable EXECUTABLE · string

Python executable to use for finding PEP 561 packages.

mypy --python-executable /usr/bin/python3.11 src/

--no-site-packages · boolean

Do not search for installed PEP 561 packages.

mypy --no-site-packages src/

--no-silence-site-packages · boolean

Report errors in installed packages.

mypy --no-silence-site-packages src/

Disallow dynamic typing

--disallow-any-unimported · boolean

Disallow Any types from unfollowed imports.

mypy --disallow-any-unimported src/

--disallow-any-expr · boolean

Disallow all expressions that have type Any.

mypy --disallow-any-expr src/

--disallow-any-decorated · boolean

Disallow functions with Any in signature after decorator transformation.

mypy --disallow-any-decorated src/

--disallow-any-explicit · boolean

Disallow explicit Any in type positions.

mypy --disallow-any-explicit src/

--disallow-any-generics · boolean

Disallow generic types without explicit type parameters.

mypy --disallow-any-generics src/

--disallow-subclassing-any · boolean

Disallow subclassing values of type Any.

mypy --disallow-subclassing-any src/

Untyped definitions and calls

--disallow-untyped-calls · boolean

Disallow calling untyped functions from typed functions.

mypy --disallow-untyped-calls src/

--untyped-calls-exclude MODULE · string

Exclude specific packages/modules from --disallow-untyped-calls.

mypy --disallow-untyped-calls --untyped-calls-exclude=third_party src/

--disallow-untyped-defs · boolean

Disallow defining functions without type annotations.

mypy --disallow-untyped-defs src/

--disallow-incomplete-defs · boolean

Disallow defining functions with incomplete type annotations.

mypy --disallow-incomplete-defs src/

--check-untyped-defs · boolean

Type check the interior of functions without type annotations.

mypy --check-untyped-defs src/

--disallow-untyped-decorators · boolean

Disallow decorating typed functions with untyped decorators.

mypy --disallow-untyped-decorators src/

None and Optional handling

--strict-optional · boolean · default: "True"

Enable strict checking of optional types and None values.

mypy --strict-optional src/

--no-strict-optional · boolean

Disable strict optional checking.

mypy --no-strict-optional src/

Not recommended. This makes None compatible with all types.

--implicit-optional · boolean

Treat arguments with None default as having optional type.

mypy --implicit-optional src/

Warnings

--warn-redundant-casts · boolean

Warn about redundant casts.

mypy --warn-redundant-casts src/

--warn-unused-ignores · boolean

Warn about unneeded # type: ignore comments.

mypy --warn-unused-ignores src/

--no-warn-no-return · boolean

Don’t warn about missing return statements.

mypy --no-warn-no-return src/

--warn-return-any · boolean

Warn when returning Any from non-Any function.

mypy --warn-return-any src/

--warn-unreachable · boolean

Warn about unreachable code.

mypy --warn-unreachable src/

Strictness flags

--strict · boolean

Enable all optional error checking flags.

mypy --strict src/

This is equivalent to enabling: --disallow-any-generics, --disallow-untyped-calls, --disallow-untyped-defs, --disallow-incomplete-defs, --check-untyped-defs, --disallow-untyped-decorators, --warn-redundant-casts, --warn-unused-ignores, --warn-return-any, --no-implicit-reexport, --strict-equality, --strict-concatenate, --extra-checks

--allow-untyped-globals · boolean

Suppress errors caused by not being able to infer types of global/class variables.

mypy --allow-untyped-globals src/

--allow-redefinition · boolean

Allow variable redefinition with arbitrary types.

mypy --allow-redefinition src/

--local-partial-types · boolean

Disallow partial types spanning module top level and function.

mypy --local-partial-types src/

--no-implicit-reexport · boolean

Require explicit re-export using from ... as ... or __all__.

mypy --no-implicit-reexport src/

--strict-equality · boolean

Prohibit equality/identity/container checks between non-overlapping types.

mypy --strict-equality src/

--extra-checks · boolean

Enable additional checks that are technically correct but impractical.

mypy --extra-checks src/

Error codes

--enable-error-code ERROR_CODE · string

Enable specific error codes.

mypy --enable-error-code truthy-bool,ignore-without-code src/

--disable-error-code ERROR_CODE · string

Disable specific error codes.

mypy --disable-error-code misc,no-untyped-def src/

Error message formatting

--show-error-context · boolean

Show context in error messages.

mypy --show-error-context src/

--show-column-numbers · boolean

Show column numbers in error messages.

mypy --show-column-numbers src/

--show-error-code-links · boolean

Show documentation links for error codes.

mypy --show-error-code-links src/

--hide-error-codes · boolean

Hide error codes in error messages.

mypy --hide-error-codes src/

--pretty · boolean

Use visually nicer output with soft word wrap and source snippets.

mypy --pretty src/

--no-color-output · boolean

Disable color in error messages.

mypy --no-color-output src/

--no-error-summary · boolean

Hide error summary.

mypy --no-error-summary src/

--show-absolute-path · boolean

Show absolute paths in error messages.

mypy --show-absolute-path src/

Incremental mode

--no-incremental · boolean

Disable incremental mode.

mypy --no-incremental src/

--cache-dir DIR · string · default: ".mypy_cache"

Store cache info in the specified directory.

mypy --cache-dir /tmp/mypy_cache src/

--sqlite-cache · boolean

Use SQLite database for cache storage.

mypy --sqlite-cache src/

--cache-fine-grained · boolean

Include fine-grained dependencies in cache.

mypy --cache-fine-grained src/

--skip-version-check · boolean

Use cache even if generated by different Mypy version.

mypy --skip-version-check src/

--skip-cache-mtime-checks · boolean

Skip cache internal consistency checks based on mtime.

mypy --skip-cache-mtime-checks src/

Reports

Report generation disables incremental mode and slows down checking.

--any-exprs-report DIR · string

Generate a report of Any expressions.

mypy --any-exprs-report reports/ src/

--html-report DIR · string

Generate an HTML coverage report.

mypy --html-report htmlcov/ src/

--linecount-report DIR · string

Generate a line count report.

mypy --linecount-report reports/ src/

--linecoverage-report DIR · string

Generate a JSON line coverage report.

mypy --linecoverage-report reports/ src/

Advanced options

--plugins PLUGIN · string

Specify Mypy plugins to use.

mypy --plugins pydantic.mypy src/

--exclude PATTERN · string

Exclude files/directories matching the pattern.

mypy --exclude '/tests/' src/

--verbose · boolean

Show more verbose messages.

mypy --verbose src/

--pdb · boolean

Invoke debugger on fatal error.

mypy --pdb src/

--show-traceback · boolean

Show traceback on fatal error.

mypy --show-traceback src/

--raise-exceptions · boolean

Raise exceptions on fatal errors (for debugging).

mypy --raise-exceptions src/

Output options

--junit-xml FILE · string

Write a JUnit XML file with type checking results.

mypy --junit-xml junit.xml src/

--junit-format {global,per_file} · choice · default: "global"

Format for JUnit XML output.

mypy --junit-xml junit.xml --junit-format per_file src/

Combining flags

Strict checking

mypy --strict \
  --show-error-codes \
  --pretty \
  src/