Re: [RFC PATCH 2/4] test-lib: allow testing another git build tree

Thomas Rast [off-list ref] writes:

On Wednesday 14 December 2011 19:07:35 Junio C Hamano wrote:

quoted

Thomas Rast [off-list ref] writes:

quoted

The perf-lib work wants this feature, so we may as well do it for
test-lib in general.

How is this different from what GIT_TEST_INSTALLED already gives us
(other than "needs more diskspace to keep another source tree fully
built", that is)?

I was scared away by the note that it would use (among others) perl
libs from the current build tree.  Upon investigation I also see that
the test-* situation is still not satisfactory.  Some (like
test-chmtime) are used by the tests for a vital task, and if they ever
have to be fixed, we would want to use the fixed version in any "test
an old git" run.  OTOH, others (e.g., test-dump-cache-tree) are linked
with the rest of the code and serve to test an otherwise not
accessible part of it, and testing an old git should use them from the
tested tree.

Okay, so GIT_BUILD_DIR variant should now use everything from the tree
being tested for consistency to improve the situation, right?

Ehh, not quite, if you worry about an old one having broken test-chmtime,
you actively do not want that consistency; how is that addressed?

Not that I think we should address such issues---these standalone programs
tend to be small and simple, so always using them from the tree being
tested is a much better policy than using them from the tree you are
running the tests from.

The disk space argument is moot IMO:

I was not really worried about "space" (disks are cheap) but more about
mental burden of having to keep multiple build trees in the source area.
Keeping multiple installed versions is already necessary to be able to
quickly respond to "I am using Git version X and this does not work".