[OE-core] OE-Core and Bitbake wrapper changes (min 2.7.3 python version)

[Mark Hatle]

On 6/7/13 10:12 AM, Richard Purdie wrote:
> On Fri, 2013-06-07 at 10:06 -0500, Mark Hatle wrote:
>> On 6/7/13 5:47 AM, Richard Purdie wrote:
>>> Its not secret that I hate the current bitbake wrapper script and want
>>> to remove it for 101 different reasons.
>>>
>>> I now have code which removes the need for the double execution of
>>> bitbake which was the only fundamental reason we had it. The question
>>> therefore remains, what to do with the other pieces of the wrapper,
>>> specifically the tar and git versions checks.
>>>
>>> As a reminder for those who don't remember the problem here, the git
>>> version is checked since we use certain parameters in the git fetcher
>>> which need certain versions of git and git is in ASSUME_PROVIDED these
>>> days. Its possible to trigger git operations at part time to resolve
>>> revisions. tar is even more ugly since the wrong version has issues
>>> extracting sstate archives. These issues mean injecting building them
>>> into the dependency chain at the right point is hard.
>>>
>>> Personally, I think we carry around a bit too much legacy these days and
>>> its starting to hurt us. I would therefore like to propose that we take
>>> this opportunity to do some spring cleaning and simply error on:
>>>
>>> * broken tar versions
>>> * too old versions of git
>>> * python < 2.7.3
>>>
>>> The python version check would move to the oe-init-build-env script, the
>>> git/tar versions to sanity.bbclass.
>>
>> Can we also add the python check to bitbake as well?  My concern is not everyone
>> uses the oe-init-build-env script, so ensuring that bitbake stops immediately
>> and tells the user what's wrong is important.
>
> We do have checks in there and these will move to the new versions. The
> issue we've had before is that you get a syntax error from python trying
> to *parse* bin/bitbake. We obviously try and avoid that but it can slip
> in for older python versions.
>
>>> The recommendation for anyone with these older versions would be to
>>> install our standalone tools tarball which would have python 2.7.3 and
>>> working versions of tar/git.
>>>
>>> The reason for the python version change is so we can embrace the
>>> unittest improvements in 2.7 and drop all of the workarounds for pre
>>> 2.7.3 bugs in bitbake. This starts to move us towards python 3, if this
>>> tarball works well, we'd use the same approach to move to python 3.
>>>
>>> Any objections?
>>
>> No objection, this seems fine.  It would be nice if there was a simple way (for
>> the tar and git cases) to be able to build them as a user step and then be able
>> to use them, but that "nice experience" can easily be handled by documentation
>> as well.
>
> "bitbake tar-native-replacement git-native-replacement" will still be
> available as things stand but you'd have to put something into the
> sanity check to look at the recipes being targeted and skip the sanity
> tests. Its complexity I'd prefer not to have and will suck from a
> usability perspective since the user would have to remember to do this
> each time. The question "can't bitbake do this itself" then comes back
> but you really do need a wrapper as there is too much version specific
> knowledge. So in summary, I don't want to go here for the rapidly
> reducing number of users this affects.

Sorry, I wasn't clear.  I meant that when it fails, it points the user at 
documentation that explains how they can build git/tar, etc..  Adding the code 
to do the build automatically should not be needed.

> Cheers,
>
> Richard
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