Re: git aliases and GIT_PREFIX

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