[issue38924] pathlib paths .normalize()

[Ionuț Ciocîrlan]

Ionuț Ciocîrlan <ionut.ciocirlan at gmail.com> added the comment:

> Can you please add an example of how normalize() should behave?

```
>>> mypath = PurePosixPath("foo/bar/bzz")
>>> mypath /= "../../"
>>> mypath
PurePosixPath('foo/bar/bzz/../..')
>>> mypath = mypath.normalize()
>>> mypath
PurePosixPath('foo')
>>> mypath /= "../../../there"
>>> mypath
PurePosixPath('foo/../../../there')
>>> mypath = mypath.normalize()
>>> mypath
PurePosixPath('../../there')
>>> mypath /= "../../and/back/again"
>>> mypath
PurePosixPath('../../there/../../and/back/again')
>>> mypath = mypath.normalize()
>>> mypath
PurePosixPath('../../../and/back/again')
```

> I assume you want the same behaviour as os.path.normpath which already accepts a pathlike object to be added to pathlib.

Yes, exactly the same behaviour, but arguing that normpath() can take a pathlib object is just saying that it saves you from doing an intermediate str(), which is, well, nice, but still not pretty. Consider `mypath = mypath.normalize()` vs. `mypath = PurePosixPath(normpath(mypath))`.

> Do note that Path inherits from PurePath, so providing a normalize() method on the latter means it will end up on the former.

That could be "circumvented" with a bit of code shuffling, e.g. moving everything from `PurePath` to a `PathBase` or `_Path` or somesuch, and forking the inheritance from there. On the other hand, it might be useful. I personally can't think of a scenario, but the GNU folk certainly think so, see `realpath --logical`: https://www.gnu.org/software/coreutils/manual/html_node/realpath-invocation.html

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<https://bugs.python.org/issue38924>
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