Mapping file paths to modules

One of the main ways you can tell mypy what files to type checkis by providing mypy the paths to those files. For example:

$ mypy file_1.py foo/file_2.py file_3.pyi some/directory

This section describes how exactly mypy maps the provided pathsto modules to type check.

• Files ending in .py (and stub files ending in .pyi) arechecked as Python modules.
• Files not ending in .py or .pyi are assumed to be Pythonscripts and checked as such.
• Directories representing Python packages (i.e. containing ainit.py[i] file) are checked as Python packages; allsubmodules and subpackages will be checked (subpackages mustthemselves have a init.py[i] file).
• Directories that don’t represent Python packages (i.e. not directlycontaining an init.py[i] file) are checked as follows:
  • All *.py[i] files contained directly therein are checked astoplevel Python modules;
  • All packages contained directly therein (i.e. immediatesubdirectories with an init.py[i] file) are checked astoplevel Python packages.

One more thing about checking modules and packages: if the directorycontaining a module or package specified on the command line has aninit.py[i] file, mypy assigns these an absolute module name bycrawling up the path until no init.py[i] file is found.

For example, suppose we run the command mypy foo/bar/baz.py wherefoo/bar/init.py exists but foo/init.py does not. Thenthe module name assumed is bar.baz and the directory foo isadded to mypy’s module search path.

On the other hand, if foo/bar/init.py did not exist, foo/barwould be added to the module search path instead, and the module nameassumed is just baz.

If a script (a file not ending in .py[i]) is processed, the modulename assumed is main (matching the behavior of thePython interpreter), unless —scripts-are-modules is passed.