mypy
Optional static typing checks for python
If you don't use python static typing, you should disable this linter by adding PYTHON_MYPY in DISABLE_LINTERS variable in your .mega-linter.yml config file
mypy documentation
- Version in MegaLinter: 1.9.0
- Visit Official Web Site
- See How to configure mypy rules
- If custom
.mypy.iniconfig file isn't found, .mypy.ini will be used
- If custom
- See How to disable mypy rules in files
Configuration in MegaLinter
- Enable mypy by adding
PYTHON_MYPYin ENABLE_LINTERS variable - Disable mypy by adding
PYTHON_MYPYin DISABLE_LINTERS variable
| Variable | Description | Default value |
|---|---|---|
| PYTHON_MYPY_ARGUMENTS | User custom arguments to add in linter CLI call Ex: -s --foo "bar" |
|
| PYTHON_MYPY_COMMAND_REMOVE_ARGUMENTS | User custom arguments to remove from command line before calling the linter Ex: -s --foo "bar" |
|
| PYTHON_MYPY_FILTER_REGEX_INCLUDE | Custom regex including filter Ex: (src\|lib) |
Include every file |
| PYTHON_MYPY_FILTER_REGEX_EXCLUDE | Custom regex excluding filter Ex: (test\|examples) |
Exclude no file |
| PYTHON_MYPY_CLI_LINT_MODE | Override default CLI lint mode - file: Calls the linter for each file- list_of_files: Call the linter with the list of files as argument- project: Call the linter from the root of the project |
list_of_files |
| PYTHON_MYPY_FILE_EXTENSIONS | Allowed file extensions. "*" matches any extension, "" matches empty extension. Empty list excludes all filesEx: [".py", ""] |
[".py"] |
| PYTHON_MYPY_FILE_NAMES_REGEX | File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files Ex: ["Dockerfile(-.+)?", "Jenkinsfile"] |
Include every file |
| PYTHON_MYPY_PRE_COMMANDS | List of bash commands to run before the linter | None |
| PYTHON_MYPY_POST_COMMANDS | List of bash commands to run after the linter | None |
| PYTHON_MYPY_UNSECURED_ENV_VARIABLES | List of env variables explicitly not filtered before calling PYTHON_MYPY and its pre/post commands | None |
| PYTHON_MYPY_CONFIG_FILE | mypy configuration file nameUse LINTER_DEFAULT to let the linter find it |
.mypy.ini |
| PYTHON_MYPY_RULES_PATH | Path where to find linter configuration file | Workspace folder, then MegaLinter default rules |
| PYTHON_MYPY_DISABLE_ERRORS | Run linter but consider errors as warnings | false |
| PYTHON_MYPY_DISABLE_ERRORS_IF_LESS_THAN | Maximum number of errors allowed | 0 |
| PYTHON_MYPY_CLI_EXECUTABLE | Override CLI executable | ['mypy'] |
IDE Integration
Use mypy in your favorite IDE to catch errors before MegaLinter !
MegaLinter Flavours
This linter is available in the following flavours
| Flavor | Description | Embedded linters | Info | |
|---|---|---|---|---|
 |
all | Default MegaLinter Flavor | 122 |   |
| cupcake | MegaLinter for the most commonly used languages | 84 |   |
|
| python | Optimized for PYTHON based projects | 64 |   |
Behind the scenes
How are identified applicable files
- File extensions:
.py
How the linting is performed
- mypy is called once with the list of files as arguments (
list_of_filesCLI lint mode)
Example calls
mypy myfile.py
mypy --config-file .mypy.yml myfile.py
Help content
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 {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
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 Support 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-subclassing-
any)
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: --allow-
incomplete-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-strict-
optional
--implicit-optional Assume arguments with default values of None are
Optional (inverse: --no-implicit-optional)
--no-strict-optional Disable strict Optional checks (inverse: --strict-
optional)
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 non-
Any typed functions (inverse: --no-warn-return-
any)
--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-strict-
equality)
--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: --no-
extra-checks)
--strict Strict mode; enables the following flags: --warn-
unused-configs, --disallow-any-generics,
--disallow-subclassing-any, --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, --extra-
checks
--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: --color-
output)
--no-error-summary Do not show error stats summary (inverse: --error-
summary)
--show-absolute-path Show absolute paths to files (inverse: --hide-
absolute-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: --no-
warn-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: --no-
explicit-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 MODULE
Type-check module; can repeat for more modules
-p PACKAGE, --package PACKAGE
Type-check package recursively; can be repeated
-c PROGRAM_TEXT, --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.
Installation on mega-linter Docker image
- Dockerfile commands :
ENV MYPY_CACHE_DIR=/tmp
- PIP packages (Python):