On Thu, Apr 15, 2021 at 9:36 AM David Mertz <me...@gnosis.cx> wrote:
> On Thu, Apr 15, 2021 at 4:55 PM Christopher Barker <python...@gmail.com>
> wrote:
>
>> Presumably that's why importlib.metadata exists in the stdlib.
>>
>
> I was so hopeful about this, but in the end... not really. I have not
> used this capability before. Here are a few different situations I know of:
>
> >>> import re, statistics, pandas, vaex, bs4
> >>> for mod in [re, statistics, pandas, vaex, bs4]:
> ... try:
> ... print(mod.__name__, end=" ")
> ... print(mod.__version__)
> ... except:
> ... print("__version__ not present")
> ...
> re 2.2.1
> statistics __version__ not present
> pandas 1.2.4
> vaex {'vaex': '4.1.0', 'vaex-core': '4.1.0', 'vaex-viz': '0.5.0',
> 'vaex-hdf5': '0.7.0', 'vaex-server': '0.4.0', 'vaex-astro': '0.8.0',
> 'vaex-jupyter': '0.6.0', 'vaex-ml': '0.11.1'}
> bs4 4.9.3
>
> >>> for mod in [re, statistics, pandas, vaex, bs4]:
> ... try:
> ... print(mod.__name__, version(mod.__name__))
> ... except Exception as err:
> ... print(mod.__name__, repr(err))
> ...
> re PackageNotFoundError('re')
> statistics PackageNotFoundError('statistics')
> pandas 1.2.4
> vaex 4.1.0
> bs4 PackageNotFoundError('bs4')
>
> It seems like (somehow or another) importlib.metadata is doing something
> perhaps more useful for vaex. But it is doing distinctly worse for re,
> statistics, and bs4.
>
I don't see how importlib.metadata plays into your code sample since you
didn't import it to use it?
>
> Version is arguably useful from the package user side. As I believe Victor
>> mentioned, there are two uses for version information: display to the user
>> -- for which version strings are fine, or programmatic comparison -- for
>> which something like the Version object is very helpful. Do we only need to
>> use version information programmatically when we are creating (or
>> installing) packages? I don't think so -- I know I have code that (poorly)
>> does version checking programmatically.
>>
>
And is installing a dependency that much of a burden for that code?
>
> I think the key thing that Chris and I are pointing to is that there is a
> definite use for versions that is NOT for package maintainers/creators.
> Interactive use is definitely one such case, and eyeballing something, even
> if it is the oddball use that Vaex has, can help with figuring out an
> issue. But in actual code, I relatively often do something like this. Or
> rather, the below is what I would find really nice to be able to do.
>
> ver = robust_version(module)
> if ver >= (5, 2, 1):
> doit_modern_style()
> elif ver < (5, 2, 1):
> doit_old_style
> else:
> doit_unversioned_style()
>
> I'd like code like that to ALWAYS succeed. No exceptions raised. And it
> would *usually* use reasonable heuristics to figure out some sort of
> structured version info as well as is possible. I.e. probably look in
> several places and return some custom object that represents a "best
> effort." That object might be like NaN in being neither less than nor more
> than other things, in the fallback case.
>
All doable with importlib.metadata and 'packaging'.
-Brett
>
> --
> The dead increasingly dominate and strangle both the living and the
> not-yet born. Vampiric capital and undead corporate persons abuse
> the lives and control the thoughts of homo faber. Ideas, once born,
> become abortifacients against new conceptions.
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