Subject: Re: [PATCH 0/4] Add more tests of cvsimport

From: Michael Haggerty <[email-masked]>
Date: Fri, 20 Feb 2009 11:21:38 +0100

Jeff King wrote:
> On Fri, Feb 20, 2009 at 06:18:09AM +0100, Michael Haggerty wrote:
> [...]
> I do wonder, though, whether it would be simpler to make a "cvs import
> test suite" that could pluggably test cvs2svn, git-cvsimport, or other
> converters. Then you could test each on the exact same set of test
> repos. And abstracting "OK, now make a repository from this cvsroot"
> wouldn't be that hard for each command (I wouldn't think, but obviously
> I haven't tried it :) ).

Many tests only need to compare the contents of branches/tags checked
out of CVS with those checked out of the converted repository.  Such
tests could pretty easily be made agnostic about what conversion tool
they are testing and also, for that matter, the type of the target VCS
(git, SVN, hg, ...).  Testing incremental conversions at that level of
detail would not be much harder.

But other tests would be harder to write in a neutral fashion.  For
example, the cvs2svn test suite has tests of log messages, character-set
conversions of metadata, correct commit ordering, branching topology, etc.

In fact, one of the many things I haven't gotten around to yet is
writing a nontrivial test suite for cvs2git.  I'd like to share as much
as possible with the cvs2svn test suite, but there is a lot there that
is SVN-specific.

>> Patch 1 splits out some code into a library usable by multiple
>> CVS-related tests.
> 
> That is definitely a good first step, though the usual naming convention
> is t/lib-cvs.sh. See t/lib-{git-svn,httpd,rebase}.sh, for example.

Thanks, I hadn't noticed that.  I'll change it the v2 of the patch.

>> Patch 2 changes the library to add the -f option when invoking cvs (to
>> make it ignore the user's ~/.cvsrc file).
> 
> The code in t9600 (which gets moved to lib-cvs in your patch 1) sets
> HOME explicitly. So is this really a problem?

That's a good question.  I just checked, and empirically cvs uses .cvsrc
from my true home directory even if HOME is set differently.  So I think
that the -f option is indeed necessary.

>> Patch 4 adds a new test script t9601 that tests "git cvsimport"'s
>> handling of CVS vendor branches.  One of these tests fails due to an
>> actual bug.
> 
> Cool. Are you volunteering to fix git-cvsimport, too? :)

Not unless you call cvs2git the fixed version :-)

>> Finally, the *,v files comprising the CVS repository have blank
>> trailing lines, triggering a warning from "git diff --check".  I don't
>> think that CVS strictly requires the blank lines, but they are always
>> generated by CVS, so I left them in.  But if the "git diff --check"
>> warnings are considered a serious problem, the blank lines could
>> probably be removed.
> 
> It's best to leave them in, I think, to create as realistic a test as
> possible. But you should mark the paths as "we don't care about
> whitespace" using gitattributes. I.e.,:
> 
> diff --git a/t/t9601/.gitattributes b/t/t9601/.gitattributes
> new file mode 100644
> index 0000000..562b12e
> --- /dev/null
> +++ b/t/t9601/.gitattributes
> @@ -0,0 +1 @@
> +* -whitespace

Cool, I didn't know about that feature.  I'll include that in v2 as well.

Thanks for the feedback!

BTW, I don't want to trash "git cvsimport".  I'm not brave enough even
to try to implement incremental conversions in cvs2git.  So the fact
that cvsimport sometimes works is already impressive :-)  I also
understand that its limitations come from those of cvsps, another
impressive but flawed tool (which in turn is being used outside of its
design limits).  But I hope to raise awareness that cvsps-based tools
are not the best choice for "one-shot" conversions, and maybe work
against people's tendency to use the "default" tool unless it obviously
blows up.

Michael