Add suffix property to zipfile.Path

[MrQubo]

BPO	44095
Nosy	@jaraco, @miguendes, @MrQubo
PRs	bpo-44095: Add suffix, stem and suffixes to zipfile.Path #26129

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-05-14.18:00:17.721>
created_at = <Date 2021-05-10.05:29:23.213>
labels = ['type-feature', 'library', '3.11']
title = 'Add suffix property to zipfile.Path'
updated_at = <Date 2021-05-14.18:00:17.720>
user = 'https://github.com/MrQubo'

bugs.python.org fields:

activity = <Date 2021-05-14.18:00:17.720>
actor = 'jaraco'
assignee = 'none'
closed = True
closed_date = <Date 2021-05-14.18:00:17.721>
closer = 'jaraco'
components = ['Library (Lib)']
creation = <Date 2021-05-10.05:29:23.213>
creator = 'MrQubo'
dependencies = []
files = []
hgrepos = []
issue_num = 44095
keywords = ['patch']
message_count = 6.0
messages = ['393352', '393637', '393650', '393671', '393682', '393683']
nosy_count = 3.0
nosy_names = ['jaraco', 'miguendes', 'MrQubo']
pr_nums = ['26129']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue44095'
versions = ['Python 3.11']

[MrQubo]

suffix property is present on pathlib.Path (specifically pathlib.PurePath) and it could also be added to zipfile.Path for consistency.

My use case is filtering files by suffix:
patch_files = list(filter(lambda file: file.suffix == '.patch', files))

Besides suffix also most of the other pathlib.PurePath properties and methods could be added.

[miguendes]

+1.

The docstring says:

class Path:
    """
    A pathlib-compatible interface for zip files.

but only a few methods are supported. It'd be nice to have at least stem, parents, suffixes, parts, which IMHO would make sense here.

I'd love to work on this if the Core Devs think it makes sense and if OP is not doing so also.

[MrQubo]

Thank for your interest Miguel. I have no experience with CPython codebase so I'll be glad if you work on this.

I think treating ZipFile's like a separate drive would be the best. If we agree on this then probably all of the properties and methods from pathlib could be implemented. But without this at least suffix, suffixes, stem, with_name(), with_stem(), and with_suffix() makes perfect sense.

If some of the properties/methods won't be implemented on zipfile.Path then it would be useful to raise NotImplementedError. Currently, trying to use suffix property, raises the error AttributeError: 'Path' object has no attribute 'suffix'. This is confusing as the name of the class is the same as in pathlib.Path so it's not immediately obvious that it meant zipfile.Path.

The use-case for mimicking those two interfaces closely is to use both interchangeably (thanks to duck-typing).

[miguendes]

I prototyped something by adding suffix, suffixes, and stem. To me these are the most obvious ones and would be useful right away.

Regarding the others I'm not so sure. It seems that zipfile.Path is just a convenient class to provide basic navigational operations. It's not meant to be 100% consistent with pathlib.Path.

In any case, it'd nice to discuss it.

Here it is: #26129

[jaraco]

Sounds good to me. In general, it's easier to contribute first to https://github.com/jaraco/zipp and those changes can be readily merged into CPython. No worries, though. If these changes can be accepted here, I should be able to graft them onto jaraco/zipp as well, and thus provide the functionality for older Pythons.

At this point, Python 3.10 is frozen for features, which this change would be, so I'm updating the target version to 3.11.

It's not meant to be 100% consistent with pathlib.Path.

That's right. It's meant to provide whatever consistency makes sense, but a subset of what's available on pathlib.Path. Happy to accept any contributions that would be useful.

> A pathlib-compatible interface
only a few methods are supported

Indeed, perhaps the documentation should be more clear about what is and isn't supported.

[jaraco]

Thanks for the excellent patch. I've created jaraco/zipp#74 to track the backport of these changes.