test-lib: set GIT_CEILING_DIRECTORIES to protect the surrounding repository

Every once in a while a test somehow manages to escape from its trash
directory and modifies the surrounding repository, whether because of
a bug in git itself, a bug in a test [1], or e.g. when trying to run
tests with a shell that is, in general, unable to run our tests [2].

Set GIT_CEILING_DIRECTORIES="$TRASH_DIRECTORY/.." as an additional
safety measure to protect the surrounding repository at least from
modifications by git commands executed in the tests (assuming that
handling of ceiling directories during repository discovery is not
broken, and, of course, it won't save us from regular shell commands,
e.g. 'cd .. && rm -f ...').

[1] e.g. https://public-inbox.org/git/20210423051255.GD2947267@szeder.dev
[2] $ git symbolic-ref HEAD
    refs/heads/master
    $ ksh ./t2011-checkout-invalid-head.sh
    [... a lot of "not ok" ...]
    $ git symbolic-ref HEAD
    refs/heads/other

    (In short: 'ksh' doesn't support the 'local' builtin command,
    which is used by 'test_oid', causing it to return with error
    whenever it's called, leaving ZERO_OID set to empty, so when the
    test 'checkout main from invalid HEAD' runs 'echo $ZERO_OID
    >.git/HEAD' it writes a corrupt (not invalid) HEAD, and subsequent
    git commands don't recognize the repository in the trash directory
    anymore, but operate on the surrounding repo.)

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
SZEDER Gábor 2021-08-29 11:25:36 +02:00 committed by Junio C Hamano
parent 225bc32a98
commit 614c3d8f2e

View file

@ -1343,7 +1343,8 @@ fi
GIT_TEMPLATE_DIR="$GIT_BUILD_DIR"/templates/blt
GIT_CONFIG_NOSYSTEM=1
GIT_ATTR_NOSYSTEM=1
export PATH GIT_EXEC_PATH GIT_TEMPLATE_DIR GIT_CONFIG_NOSYSTEM GIT_ATTR_NOSYSTEM
GIT_CEILING_DIRECTORIES="$TRASH_DIRECTORY/.."
export PATH GIT_EXEC_PATH GIT_TEMPLATE_DIR GIT_CONFIG_NOSYSTEM GIT_ATTR_NOSYSTEM GIT_CEILING_DIRECTORIES
if test -z "$GIT_TEST_CMP"
then