tests: add set/unset GIT_DIR pairs where appropriate

There are quite a few tests that assume that the default of the
`safe.bareRepository` setting is that it allows discovery of bare
repositories. This is unsafe. To allow the default to change, this
commit tackles a couple of places in the test suite: By setting GIT_DIR
after changing the current working directory to the bare repository,
Git no longer needs to discover it, and by unsetting GIT_DIR as soon
as leaving said directory, Git once again returns to the regular
programming of discovering the `.git` directory.

This commit can be validated mechanically by running the following
command-line:

  git diff HEAD^! | awk '
      /^diff/,/^\+\+\+/ { next }
      /^-/ { old[m++] = substr($0,2) }
      /^\+/ {
        new = substr($0,2)
        # undo: strip GIT_DIR export
        gsub(/ GIT_DIR=[.] && export GIT_DIR &&/, "", new)
        # undo: strip sane_unset GIT_DIR
        gsub(/ && sane_unset GIT_DIR/, "", new)
        if (old[n++] != new) print old[n-1] " != " new
      }'

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

t/t1400-update-ref.sh

@@ -29,10 +29,10 @@ test_expect_success setup '
 	git checkout --orphan main &&
 	create_test_commits "" &&
 	mkdir $bare &&
-	cd $bare &&
+	cd $bare && GIT_DIR=. && export GIT_DIR &&
 	git init --bare -b main &&
 	create_test_commits "bare" &&
-	cd -
+	cd - && sane_unset GIT_DIR
 '
 
 test_expect_success "create $m" '

t/t1800-hook.sh

@@ -533,9 +533,9 @@ test_expect_success 'server hooks expect stdout redirected to stderr' '
 	test_when_finished "rm -f stdout.actual stderr.actual" &&
 	git init --bare remote-server &&
 	git remote add origin-server remote-server &&
-	cd remote-server &&
+	cd remote-server && GIT_DIR=. && export GIT_DIR &&
 	setup_hooks pre-receive update post-receive post-update &&
-	cd .. &&
+	cd .. && sane_unset GIT_DIR &&
 	git push origin-server HEAD:new-branch >stdout.actual 2>stderr.actual &&
 	check_stdout_merged_to_stderr pre-receive update post-receive post-update
 '

t/t2400-worktree-add.sh

@@ -198,7 +198,7 @@ test_expect_success '"add" default branch of a bare repo' '
 test_expect_success '"add" to bare repo with worktree config' '
 	(
 		git clone --bare . bare3 &&
-		cd bare3 &&
+		cd bare3 && GIT_DIR=. && export GIT_DIR &&
 		git config extensions.worktreeconfig true &&
 
 		# Add config values that are erroneous to have in
@@ -212,7 +212,7 @@ test_expect_success '"add" to bare repo with worktree config' '
 		git config --worktree bogus.key value &&
 		git config --unset core.bare &&
 		git worktree add ../there4 main &&
-		cd ../there4 &&
+		cd ../there4 && sane_unset GIT_DIR &&
 
 		# Simple check that a Git command does not
 		# immediately fail with the current setup

t/t5500-fetch-pack.sh

@@ -454,11 +454,11 @@ test_expect_success 'fetch in shallow repo unreachable shallow objects' '
 	(
 		git clone --bare --branch B --single-branch "file://$(pwd)/." no-reflog &&
 		git clone --depth 1 "file://$(pwd)/no-reflog" shallow9 &&
-		cd no-reflog &&
+		cd no-reflog && GIT_DIR=. && export GIT_DIR &&
 		git tag -d TAGB1 TAGB2 &&
 		git update-ref refs/heads/B B~~ &&
 		git gc --prune=now &&
-		cd ../shallow9 &&
+		cd ../shallow9 && sane_unset GIT_DIR &&
 		git fetch origin &&
 		git fsck --no-dangling
 	)

t/t5540-http-push-webdav.sh

@@ -40,13 +40,13 @@ test_expect_success 'setup remote repository' '
 	git commit -m initial &&
 	cd - &&
 	git clone --bare test_repo test_repo.git &&
-	cd test_repo.git &&
+	cd test_repo.git && GIT_DIR=. && export GIT_DIR &&
 	git --bare update-server-info &&
 	test_hook --setup post-update <<-\EOF &&
 	exec git update-server-info
 	EOF
 	ORIG_HEAD=$(git rev-parse --verify HEAD) &&
-	cd - &&
+	cd - && sane_unset GIT_DIR &&
 	mv test_repo.git "$HTTPD_DOCUMENT_ROOT_PATH"
 '
 

t/t5541-http-push-smart.sh

@@ -26,11 +26,11 @@ test_expect_success 'setup remote repository' '
 	git commit -m initial &&
 	cd - &&
 	git clone --bare test_repo test_repo.git &&
-	cd test_repo.git &&
+	cd test_repo.git && GIT_DIR=. && export GIT_DIR &&
 	git config http.receivepack true &&
 	git config core.logallrefupdates true &&
 	ORIG_HEAD=$(git rev-parse --verify HEAD) &&
-	cd - &&
+	cd - && sane_unset GIT_DIR &&
 	mv test_repo.git "$HTTPD_DOCUMENT_ROOT_PATH"
 '