Re: git aliases and GIT_PREFIX

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Thu, Oct 28 2021, Federico Kircheis wrote:

> Hello to everyone,
>
> today I reported what I believed to be a bug on
>
>  https://github.com/git-for-windows/git/issues/3496
>
> and learned about GIT_DIR when working with aliases and git worktree.
>
>
>
> It's annoying that GIT_DIR it is defined only if (as far as I've
> understood) working from a worktrees or submodule, as it does not seem 
> to be related to those type of repositories.
>
> This is also irritating because apparently working aliases breaks when
> being executed from those repositories.
>
>
> I believe it would be better if GIT_DIR it's either always set or
> never (could someone enlighten me why the variable is needed in first
> place?).

I don't know the full story, but a good place to start is to apply this
patch:

diff --git a/cache.h b/cache.h
index eba12487b99..84d4c8da167 100644
--- a/cache.h
+++ b/cache.h
@@ -486,7 +486,7 @@ static inline enum object_type object_type(unsigned int mode)
 }
 
 /* Double-check local_repo_env below if you add to this list. */
-#define GIT_DIR_ENVIRONMENT "GIT_DIR"
+#define GIT_DIR_ENVIRONMENT "POISON_GIT_DIR"
 #define GIT_COMMON_DIR_ENVIRONMENT "GIT_COMMON_DIR"
 #define GIT_NAMESPACE_ENVIRONMENT "GIT_NAMESPACE"
 #define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE"

If you then run the full test suite that comes with git you should get a
pretty good picture of why/how not having GIT_DIR breaks.

Surely some of those reasons are fixable, e.g. are we invoking our own
"git" with "GIT_DIR=<path> git [...]", then we can just use "git
--git-dir=<path>", some of the others might be tricky.

When I did that the failed tests were the following:

Test Summary Report
-------------------
t9401-git-cvsserver-crlf.sh                      (Wstat: 256 Tests: 18 Failed: 16)
  Failed tests:  2-8, 10-18
  Non-zero exit status: 1
t9400-git-cvsserver-server.sh                    (Wstat: 256 Tests: 45 Failed: 23)
  Failed tests:  2, 20, 22-25, 27-41, 43, 45
  Non-zero exit status: 1
t9200-git-cvsexportcommit.sh                     (Wstat: 256 Tests: 15 Failed: 13)
  Failed tests:  1-2, 4-8, 10-15
  Non-zero exit status: 1
t9402-git-cvsserver-refs.sh                      (Wstat: 256 Tests: 37 Failed: 25)
  Failed tests:  7-12, 14-24, 27-29, 31-32, 34, 36-37
  Non-zero exit status: 1
t5516-fetch-push.sh                              (Wstat: 256 Tests: 103 Failed: 3)
  Failed tests:  101-103
  Non-zero exit status: 1
t5500-fetch-pack.sh                              (Wstat: 256 Tests: 373 Failed: 6)
  Failed tests:  7, 38-42
  Non-zero exit status: 1
t7003-filter-branch.sh                           (Wstat: 256 Tests: 48 Failed: 10)
  Failed tests:  6-7, 9-14, 16, 19
  Non-zero exit status: 1
t7406-submodule-update.sh                        (Wstat: 256 Tests: 57 Failed: 1)
  Failed test:  13
  Non-zero exit status: 1
t9902-completion.sh                              (Wstat: 256 Tests: 212 Failed: 2)
  Failed tests:  11-12
  Non-zero exit status: 1
t5601-clone.sh                                   (Wstat: 256 Tests: 107 Failed: 3)
  Failed tests:  12-13, 35
  Non-zero exit status: 1
t1510-repo-setup.sh                              (Wstat: 256 Tests: 109 Failed: 26)
  Failed tests:  3-4, 6, 8-9, 14-17, 21, 23-24, 29-30, 55
                57, 59-60, 67, 69-70, 73-74, 78, 80-81
  Non-zero exit status: 1
t5310-pack-bitmaps.sh                            (Wstat: 256 Tests: 73 Failed: 1)
  Failed test:  48
  Non-zero exit status: 1
t5401-update-hooks.sh                            (Wstat: 256 Tests: 13 Failed: 9)
  Failed tests:  3-10, 12
  Non-zero exit status: 1
t5531-deep-submodule-push.sh                     (Wstat: 256 Tests: 27 Failed: 22)
  Failed tests:  2-3, 5-15, 18-20, 22-27
  Non-zero exit status: 1
t2400-worktree-add.sh                            (Wstat: 256 Tests: 71 Failed: 2)
  Failed tests:  61-62
  Non-zero exit status: 1
t3430-rebase-merges.sh                           (Wstat: 256 Tests: 25 Failed: 1)
  Failed test:  11
  Non-zero exit status: 1
t5801-remote-helpers.sh                          (Wstat: 256 Tests: 31 Failed: 28)
  Failed tests:  2, 4-17, 19-31
  Non-zero exit status: 1
t7401-submodule-summary.sh                       (Wstat: 256 Tests: 23 Failed: 1)
  Failed test:  14
  Non-zero exit status: 1
t0001-init.sh                                    (Wstat: 256 Tests: 61 Failed: 3)
  Failed tests:  10, 13, 36
  Non-zero exit status: 1
t1500-rev-parse.sh                               (Wstat: 256 Tests: 75 Failed: 7)
  Failed tests:  35-36, 45, 49-51, 59
  Non-zero exit status: 1
t1501-work-tree.sh                               (Wstat: 256 Tests: 39 Failed: 19)
  Failed tests:  4-7, 9-11, 13-15, 17-18, 24-26, 31, 33-34
                39
  Non-zero exit status: 1
t5509-fetch-push-namespaces.sh                   (Wstat: 256 Tests: 14 Failed: 1)
  Failed test:  14
  Non-zero exit status: 1
t4201-shortlog.sh                                (Wstat: 256 Tests: 25 Failed: 1)
  Failed test:  9
  Non-zero exit status: 1
t5519-push-alternates.sh                         (Wstat: 256 Tests: 8 Failed: 8)
  Failed tests:  1-8
  Non-zero exit status: 1
t6060-merge-index.sh                             (Wstat: 256 Tests: 7 Failed: 2)
  Failed tests:  6-7
  Non-zero exit status: 1
t7409-submodule-detached-work-tree.sh            (Wstat: 256 Tests: 2 Failed: 2)
  Failed tests:  1-2
  Non-zero exit status: 1
t5403-post-checkout-hook.sh                      (Wstat: 256 Tests: 8 Failed: 1)
  Failed test:  8
  Non-zero exit status: 1
t2201-add-update-typechange.sh                   (Wstat: 256 Tests: 6 Failed: 2)
  Failed tests:  5-6
  Non-zero exit status: 1
t5402-post-merge-hook.sh                         (Wstat: 256 Tests: 6 Failed: 4)
  Failed tests:  3-6
  Non-zero exit status: 1
t1515-rev-parse-outside-repo.sh                  (Wstat: 256 Tests: 4 Failed: 1)
  Failed test:  3
  Non-zero exit status: 1
Files=940, Tests=24858, 144 wallclock secs ( 6.34 usr  1.64 sys + 654.49 cusr 307.66 csys = 970.13 CPU)
Result: FAIL
make: *** [Makefile:53: prove] Error 1