[Distutils] How to specific metadata version in setup.py?

[Tres Seaver]

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Sridhar Ratnakumar wrote:
> On 2010-03-19, at 2:27 PM, Tarek Ziadé wrote:
> 
>> On Fri, Mar 19, 2010 at 5:22 PM, Tarek Ziadé <ziade.tarek at gmail.com> wrote:
>> [..]
>>> You can't do it, distutils will automatically set 1.0 or 1.1 depending
>>> on the options you have used. (and not 1.2)
>> Re-reading the current distutils (1) code, I realize that it'll switch
>> to 1.1 *only* if you have used
>> provides, requires or obsolete, so it's partially implemented.
> 
> Ok. As a result of this, PKG-INFO that contains the "Classifiers"
> fields still has 1.0 as Metadata-Version. Consequently,
> http://pypi.python.org/pypi/pkginfo fails to read extra metadata fields.
> If Tres is reading this, I had to do the following hack as a workaroud:
> 
>     from pkginfo import Distribution
>     
>     class PkgInfoFile(Distribution):
>         # Not all packages' PKG-INFO define the proper metadata
>         # For eg., modern-package-template uses the Classifiers field and yet
>         # uses 1.0 as the metadata version (Classifiers is only defined in 1.1)
>         metadata_version = '1.2' # not all PKG-INFO file have proper metadata version

If you know you want to parse '1.2' fields regardless of the version in
the PKG-INFO file, then set the 'metadata_version' attribute on the
Distribution instance before calling 'parse'. E.g.::

  from pkginfo import Distribution
  d = Distribution()
  d.metadata_version = '1.2'
  d.parse(open('/path/to/PKG-INFO').read())

The concrete classes (SDist, BDist, Develop, Installed) all take
'metadata_version' as a constructor argument, just to provide for this
case.  I'm not sure why you would define a PkgInfo class, actually:  it
needs to have a 'read' method, at least, to allow the usual operation
('extractMetadata') to work.  I think your usecase is probably covered
by either the Installed or Develop classes.  If you do have a usedase,
the public bzr branch is here:

  lp:~tseaver/pkginfo/trunk

I'll be glad to review and merge a patch which adds your support, and
make a new release.

>> The new class is much cleaner in the implementation, and so is the
>> register command for PyPI.
>>
>> Notice that we have almost finished the implementation of PEP 345 on
>> PyPI side so we will soon be able to push PEP 345 fields over there.
> 

> Wasn't PEP 345 fully implemented for distutils1? Ah, I see that it is
> still "Draft" mode.
> 
> Can I use distutils2 to parse PKG-INFO (as a replacement for the
> `pkginfo` project)? Will it read all the fields despite the
> inaccurate Metadata-Version field?

I haven't looked at 'distutils2' yet.


Tres.
- --
===================================================================
Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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