[FEATURE] Add __all__ definition to __init__

[martsa1]

Is your feature request related to a problem

Yes

When running a fairly strict mypy configuration, mypy complains that the typer module is missing all its attributes.

The solution you would like

We can resolve this by adding a __all__ definition to the top level init.

Describe alternatives you've considered

Using a less strict mypy configuration doesn't yield these errors, but that then allows typing compromises to slip into my code elsewhere.

Additional context

Sample mypy config:

[mypy]
allow_redefinition = False
check_untyped_defs = True
disallow_any_generics = True
disallow_any_unimported = True
disallow_incomplete_defs = True
disallow_subclassing_any = True
disallow_untyped_calls = True
disallow_untyped_decorators = True
disallow_untyped_defs = True
ignore_errors = False
ignore_missing_imports = True
implicit_reexport = False
local_partial_types = True
mypy_path = type_stubs
no_implicit_optional = True
strict_equality = True
strict_optional = True
warn_no_return = True
warn_redundant_casts = True
warn_return_any = True
warn_unreachable = True
warn_unused_configs = True
warn_unused_ignores = True

Sample script:

import typer


def main() -> None:
    typer.secho("hello, world!", fg=typer.colors.GREEN)


if __name__ == "__main__":
    main()

Mypy Errors:

$ mypy sample.py
sample.py:5: error: Module has no attribute "secho"; maybe "echo"?
Found 1 error in 1 file (checked 1 source file)

Adding the following to typer/__init__.py:

__all__ = [
    "Abort",
    "Argument",
    "BadParameter",
    "CallbackParam",
    "Context",
    "Exit",
    "FileBinaryRead",
    "FileBinaryWrite",
    "FileText",
    "FileTextWrite",
    "Option",
    "Typer",
    "clear",
    "colors",
    "confirm",
    "echo",
    "echo_via_pager",
    "edit",
    "format_filename",
    "get_app_dir",
    "get_binary_stream",
    "get_terminal_size",
    "get_text_stream",
    "getchar",
    "launch",
    "open_file",
    "pause",
    "progressbar",
    "prompt",
    "run",
    "secho",
    "style",
    "unstyle",
]

Resolves the above error & any others like it.

Typer version: 0.2.1, mypy version: 0.782, python: 3.6.10

[victorphoenix3]

I could work on this!

[martsa1]

If no-one gets to it I'll eventually raise a PR. I was thinking it would be worth a test to verify that the __all__ is up to date with the imports as part of such a PR. It wouldn't take very long (assuming the above list is correct), and would help ensure that any future import additions/removals are kept up to date.

I might have time the weekend after this, but if you're likely to get to it first, by all means go for it. 😄

[victorphoenix3]

• The issue arises because of the --no-implicit-reexport flag that is enabled during a --strict mypy run. It does not allow re-exporting imported modules unless the item is imported using import-x-as-x or is included in __all__ .
  In my PR I have used import x as x rather than __all__ which requires extra maintenance.
• Another option is to add implicit_reexport = True to the mypy.ini file and the import/export errors don't arise even with the strict configuration.

[victorphoenix3]

@tiangolo

[pmav99]

this is a probably a duplicate of #112

[tiangolo]

Thanks for the discussion here everyone! @victorphoenix3 added support for mypy --strict on #147.

Available in Typer version 0.3.2 🚀 🎉

[martsa1]

@victorphoenix3 Thanks for getting to this! Your implementation is much nicer than anything I would have put together!

@tiangolo Thanks for merging, and thanks for the awesome Typer. 👍