[Distutils] use of '_' in package name causing version parsing issue?

[Baiju M]

On Thu, Mar 11, 2010 at 11:05 AM, Baiju M <mbaiju at zeomega.com> wrote:
> On Thu, Mar 11, 2010 at 10:09 AM, P.J. Eby <pje at telecommunity.com> wrote:
>> At 09:50 AM 3/10/2010 +0530, Baiju M wrote:
>>>
>>> I spend some time with Buildout and setuptools code to identify the issue.
>>> I will try to explain my findings.
>>>
>>> 1. Buildout is relying on pkg_resources.Requirement.parse function to
>>>    get the "project_name" like this:
>>>
>>>     pkg_resources.Requirement.parse('jiva_interface').project_name
>>>
>>>    I can see from the code of `Requirement` class that, the `__init__`
>>>    method is deprecated and recommend to use `parse`
>>>    function.
>>
>> It is undocumented, not deprecated.  You are simply not supposed to create
>> instances via that (private) constructor.
>
> Okay, fine.  Buildout doesn't create any instance directly.
>
>>>  Does this mean that we should not use the attributes
>>>    of an instance of `Requirement` class?  This is very important as
>>>    the `parse` function return a list of instances of `Requirement` class.
>>
>> Requirement objects are documented; see:
>>
>>  http://peak.telecommunity.com/DevCenter/PkgResources#requirement-objects
>
> So, according to the EBNF given there, "_" is a valid project_name identifier:
>
>  project_name ::= identifier
>  identifier   ::= [-A-Za-z0-9_]+
>
>>>   So, if it is acceptable to use the "project_name" attribute, then
>>>   Buildout can rely on it, right ?
>>
>> Yes.
>>
>>>   According to this code, this will be the result:
>>>
>>>     pkg_resources.safe_name('jiva_interface')
>>>     'jiva-interface'
>>>
>>>   And:
>>>
>>>     pkg_resources.Requirement.parse('jiva_interface').project_name
>>>     'jiva-interface'
>>>
>>>    Is this behavior correct ?
>>
>> Yes it is. All non-alphanumeric, non-dot characters are replaced with '-' in
>> a project name.  This turns project names like e.g. "Foo's Bar Factory" into
>> their canonical form (i.e., "Foo-s-Bar-Factory").
>
> If "_" is a valid project_name identifier, why it is replaces with "-" ?

There nearly 300 packages in PyPI with "_" in the package name.
For all the packages built using Setuptools, the "Name" field in
the PKG-INFO file is replaced with "-".

I checked some of the packages built with "distutils.core" [1]
Distutils is not replacing "Name" field in PKG-INFO file
with "-".

Why Setuptools is behaving different from Distutils ?

Regards,
Baiju M

[1] http://pypi.python.org/pypi/text_table/0.02