feat: stubgen warn some modules are ignored

[tsbkw]

Print message how many modules ignored when some modules are blacklisted. see: #9599
There are two preceding pull requests exist but no updates since about one year ago.

Suppose these project structure,

a
  __init__.py
  a.py
  vendor
    __init__.py
    a.py

After this change, print messages like this. (line starts with Ignored is added)

$ python -m mypy.stubgen a
Processed 2 modules
Generated files under out/a/
Ignored 2 files

And when specified verbose flag, print message like this. (line starts with Ignored and following the lines are added)

$ python -m mypy.stubgen a -v
Processing 2 files...
Processing a
Created out/a/__init__.pyi
Processing a.a
Created out/a/a.pyi
Processed 2 modules
Generated files under out/a/
Ignored 2 modules
        ignored: a/vendor/__init__.py
        ignored: a/vendor/a.py

[sobolevn]

Generally looks like a good idea to me!
It is better to be explicit about what is not processes and why.

[sobolevn]

Suggested change

	if len(ignored_py_modules):
	if ignored_py_modules:

is enough.

[tsbkw]

Thank you for reviewing!
I fixed this, and also clarify the reason why some modules are not processed by aab77a6

[sobolevn]

what is "FAIL"?

[tsbkw]

In fact I wrote in the same way as files initialized here.

mypy/mypy/test/teststubgen.py

Line 98 in 1104810

files = {os.path.relpath(mod.path or "FAIL") for mod in py_mods}

StubSource.path may be None, so I guess the original code intend to express failure of module finding and also avoiding error which caused by passing None to os.path.relpath.
Maybe "NOT_FOUND" or just skipping mod without mod.path like below is better. Which do you think is better?

{os.path.relpath(mod.path) for mod in ignored_py_mods if mod.path is not None}

[sobolevn]

Thanks! LGTM, except one question.

I will wait for someone else to double check, because I only have one commit to stubgen. This is not something I am very familiar with.

[sobolevn]

ignored_py_mods var is not asserted here.
Do we have something to check here?

[tsbkw]

Well I checked this test case and found its name test_module_not_found is confusing because module is found at this case.

I confirmed that I didn't make any unintentional changes by checking out master branch of mypy, and modified mypy/test/teststubgen.py around L103 like below and run pytest -k StubgenCmdLine -vvv.
The result of the assert_equal(c_mods, []) is fine but assert_equal(py_mods, []) reports error because mymodule was found.

    @unittest.skipIf(sys.platform == "win32", "clean up fails on Windows")
    def test_module_not_found(self) -> None:
        current = os.getcwd()
        captured_output = io.StringIO()
        sys.stdout = captured_output
        with tempfile.TemporaryDirectory() as tmp:
            try:
                os.chdir(tmp)
                self.make_file(tmp, "mymodule.py", content="import a")
                opts = parse_options(["-m", "mymodule"])
                py_mods, c_mods = collect_build_targets(opts, mypy_options(opts))
                assert captured_output.getvalue() == ""
                assert_equal(c_mods, [])
>               assert_equal(py_mods, [])
E               AssertionError: [<mypy.stubgen.StubSource object at 0x113393190>] != []

I fixed test case name and add assertions for variables py_mods, c_mods, ignored_py_mods by 4f44401.

[tsbkw]

Really thank you for reviewing.

I will wait for someone else to double check, because I only have one commit to stubgen. This is not something I am very familiar with.

Totally fine and I will wait for another review 👍