pathlib.Path.__rtruediv__ micropython incompatability.

[BrianPugh]

I wanted to add the following magic method to the pathlib.Path object:

    def __rtruediv__(self, other):
        return Path(other, self._path)

so that the following unittest would be satisfied:

    def test_rtruediv(self):
        res = "foo" / Path("bar")
        self.assertTrue(res == Path("foo/bar"))

However, I get the following stacktrace:

Traceback (most recent call last):
  File "/Users/brianpugh/.micropython/lib/unittest/__init__.py", line 392, in run_one
  File "./tests/test_pathlib.py", line 327, in test_rtruediv
TypeError: can't convert 'Path' object to str implicitly

The __rtruediv__ method never gets called, suggesting that the str.__truediv__ gets called in a way that is different than in cpython. I'm not familiar enough with cpython or micropython internals to know str's __truediv__ implementation, but something is up.

[dlech]

Does your target have MICROPY_PY_ALL_SPECIAL_METHODS enabled?

[BrianPugh]

I no longer see the options in ports/unix/mpconfigport.h, but I added it as true. Did a clean rebuild; same issue.

[dlech]

And also MICROPY_PY_REVERSE_SPECIAL_METHODS?

[BrianPugh]

no luck setting both to true; i'm digging a lil deeper.

[BrianPugh]

I think this comment here is incorrect (as in, we shouldn't allow truediv with a string, not sure if comment is up to date with implementation):

https://github.com/micropython/micropython/blob/2e4dda3c2072c4de15ac8d51ddb471b9c3833db7/py/objstr.c#L376

I'll see if I can come up with a fix.

[BrianPugh]

Will be resolved in:

micropython/micropython#10844

Closing this issue for now.

[dpgeorge]

This (reverse inplace ops with str) is now supported in MicroPython.

[BrianPugh]

excellent! iirc i have a test somewhere just to make sure this works as expected for pathlib, I'll open a PR. Thank you very much!

[BrianPugh]

Added support in #663