completion: extract repository discovery from __gitdir()

To prepare for caching the path to the repository in the following
commit, extract the repository discovering part of __gitdir() into the
__git_find_repo_path() helper function, which stores the found path in
the $__git_repo_path variable instead of printing it.  Make __gitdir()
a wrapper around this new function.  Declare $__git_repo_path local in
the toplevel completion functions __git_main() and __gitk_main() to
ensure that it never leaks into the environment and influences
subsequent completions (though this isn't necessary right now, as
__gitdir() is still only executed in subshells, but will matter for
the following commit).

Adjust tests checking __gitdir() or any other completion function
calling __gitdir() to perform those checks in a subshell to prevent
$__git_repo_path from leaking into the test environment.  Otherwise
leave the tests unchanged to demonstrate that this change doesn't
alter __gitdir()'s behavior.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 16 insertions, 6 deletions

diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 984df05..1816ed2 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -147,19 +147,25 @@ test_expect_success '__gitdir - from command line (through $__git_dir)' '
 
 test_expect_success '__gitdir - repo as argument' '
 	echo "otherrepo/.git" >expected &&
-	__gitdir "otherrepo" >"$actual" &&
+	(
+		__gitdir "otherrepo" >"$actual"
+	) &&
 	test_cmp expected "$actual"
 '
 
 test_expect_success '__gitdir - remote as argument' '
 	echo "remote" >expected &&
-	__gitdir "remote" >"$actual" &&
+	(
+		__gitdir "remote" >"$actual"
+	) &&
 	test_cmp expected "$actual"
 '
 
 test_expect_success '__gitdir - .git directory in cwd' '
 	echo ".git" >expected &&
-	__gitdir >"$actual" &&
+	(
+		__gitdir >"$actual"
+	) &&
 	test_cmp expected "$actual"
 '
 
@@ -450,7 +456,9 @@ test_expect_success '__git_remotes - list remotes from $GIT_DIR/remotes and from
 	git remote add remote_in_config_1 git://remote_1 &&
 	test_when_finished "git remote remove remote_in_config_2" &&
 	git remote add remote_in_config_2 git://remote_2 &&
-	__git_remotes >actual &&
+	(
+		__git_remotes >actual
+	) &&
 	test_cmp expect actual
 '
 
@@ -459,8 +467,10 @@ test_expect_success '__git_is_configured_remote' '
 	git remote add remote_1 git://remote_1 &&
 	test_when_finished "git remote remove remote_2" &&
 	git remote add remote_2 git://remote_2 &&
-	verbose __git_is_configured_remote remote_2 &&
-	test_must_fail __git_is_configured_remote non-existent
+	(
+		verbose __git_is_configured_remote remote_2 &&
+		test_must_fail __git_is_configured_remote non-existent
+	)
 '
 
 test_expect_success 'setup for ref completion' '