twisted.python.versions support for SVN 1.6.1 and above

[termim]

In Subversion 1.6.1 they removed deprecated .svn/format file. The workspace format version remains the same v10. This broke twisted.python.versions. Attached patch fixes that (relative Twisted-8.2.0).

[glyph]

Thanks for your contribution! Please see TwistedDevelopment for some guidelines on getting this patch integrated more quickly. A few notes:

1. Please contribute patches from a recent version of trunk, not the latest release. Also, please base your patches from the root of the tree rather than someplace inside it; it makes it easier to review patches if they are uniform.
2. Please include some unit tests. We would generally prefer it if patches are developed in a test-driven way, since this makes it easier to achieve full code coverage. (In other words: if it's not test-driven, we can usually tell, because there are code-paths which the tests don't catch.)

Thanks again! Looking forward to an updated patch.

[termim]

fix versions.py for SVN >= 1.6.1 relative to trunk rev.27108

[termim]

Ok. Patch updated relative to the current trunk. I'm not sure regarding the unit tests. Currently this functionality (versions) has no unit tests at all.

[thijs]

I remember a patch from feisley for svn 1.5 that also didn't come with unit tests but was applied to the trunk so putting this one up for review.

[exarkun]

Things were worse in the past than we would like them to be in the future. :) Even if a past change to this code was untested, that doesn't mean future changes may be untested. This must have unit tests. Also, #3511 did include unit tests (although it also speculatively fixed the code for SVN 1.6 as well, prior to the release of SVN 1.6, which turned out to be a failure, it seems).

[exarkun]

(In [27132]) Branching to 'svn-wc-version-3905'

[exarkun]

Gave something a whack in the branch. As time goes on, I'm less enamored of this functionality. The idea was that this would help us interpret bug reports. In practice, I haven't seen that happen.

[mwh]

Assuming this branch actually fixes the problem (something I'm not in a position to test) I think this looks fine. Please land, if you can test it.

I also agree that this looks like a treadmill it would be good to get off, but that's a matter for another branch.

[exarkun]

I tried it out on Karmic which has svn 1.6.1. And buildbot is happy.

[exarkun]

(In [27184]) Merge svn-wc-version-3905

Author: termim, exarkun Reviewer: mwhudson Fixes: #3905

Update twisted.python.versions so that it can actually parse svn 1.6.1's entries files.

[feisley]

Just a thought for the future, if this functionality is going to be kept in Twisted, it might be worth considering using utilities to get this rather than inspecting the format file itself.

For example: "svn info --xml" will give you the revision in XML format that is trivial to parse.

I think it is safe to assume if we are inspecting the information from a working copy that the cli tools are available to us, and if they are not, we simply do the same thing we do if the format file is not of appropriate version.