[PATCH v4 01/12] t2407: test bisect and rebase as black-boxes

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <derrickstolee@github.com>

The tests added by d2ba271aad0 (branch: check for bisects and rebases,
2022-06-14) modified hidden state to verify the branch_checked_out()
helper. While this indeed checks that the method implementation is _as
designed_, it doesn't show that it is _correct_. Specifically, if 'git
bisect' or 'git rebase' change their back-end for preserving refs, then
these tests do not demonstrate that drift as a bug in
branch_checked_out().

Modify the tests in t2407 to actually rely on a paused bisect or rebase.
This requires adding the !SANITIZE_LEAK prereq for tests using those
builtins. The logic is still tested for leaks in the final test which
does set up that back-end directly for an error state that should not be
possible using Git commands.

Reported-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
---
 t/t2407-worktree-heads.sh | 57 +++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 26 deletions(-)

diff --git a/t/t2407-worktree-heads.sh b/t/t2407-worktree-heads.sh
index b6be42f74a2..100ab286d5c 100755
--- a/t/t2407-worktree-heads.sh
+++ b/t/t2407-worktree-heads.sh
@@ -7,13 +7,18 @@ TEST_PASSES_SANITIZE_LEAK=true
 
 test_expect_success 'setup' '
 	test_commit init &&
-	git branch -f fake-1 &&
-	git branch -f fake-2 &&
 
 	for i in 1 2 3 4
 	do
+		git checkout -b conflict-$i &&
+		echo "not I" >$i.t &&
+		git add $i.t &&
+		git commit -m "will conflict" &&
+
+		git checkout - &&
 		test_commit $i &&
 		git branch wt-$i &&
+		git branch fake-$i &&
 		git worktree add wt-$i wt-$i || return 1
 	done &&
 
@@ -44,26 +49,26 @@ test_expect_success 'refuse to overwrite: checked out in worktree' '
 	done
 '
 
-test_expect_success 'refuse to overwrite: worktree in bisect' '
-	test_when_finished rm -rf .git/worktrees/wt-*/BISECT_* &&
+test_expect_success !SANITIZE_LEAK 'refuse to overwrite: worktree in bisect' '
+	test_when_finished git -C wt-4 bisect reset &&
 
-	touch .git/worktrees/wt-4/BISECT_LOG &&
-	echo refs/heads/fake-2 >.git/worktrees/wt-4/BISECT_START &&
+	# Set up a bisect so HEAD no longer points to wt-4.
+	git -C wt-4 bisect start &&
+	git -C wt-4 bisect bad wt-4 &&
+	git -C wt-4 bisect good wt-1 &&
 
-	test_must_fail git branch -f fake-2 HEAD 2>err &&
-	grep "cannot force update the branch '\''fake-2'\'' checked out at.*wt-4" err
+	test_must_fail git branch -f wt-4 HEAD 2>err &&
+	grep "cannot force update the branch '\''wt-4'\'' checked out at.*wt-4" err
 '
 
-test_expect_success 'refuse to overwrite: worktree in rebase' '
-	test_when_finished rm -rf .git/worktrees/wt-*/rebase-merge &&
+test_expect_success !SANITIZE_LEAK 'refuse to overwrite: worktree in rebase' '
+	test_when_finished git -C wt-2 rebase --abort &&
 
-	mkdir -p .git/worktrees/wt-3/rebase-merge &&
-	touch .git/worktrees/wt-3/rebase-merge/interactive &&
-	echo refs/heads/fake-1 >.git/worktrees/wt-3/rebase-merge/head-name &&
-	echo refs/heads/fake-2 >.git/worktrees/wt-3/rebase-merge/onto &&
+	# This will fail part-way through due to a conflict.
+	test_must_fail git -C wt-2 rebase conflict-2 &&
 
-	test_must_fail git branch -f fake-1 HEAD 2>err &&
-	grep "cannot force update the branch '\''fake-1'\'' checked out at.*wt-3" err
+	test_must_fail git branch -f wt-2 HEAD 2>err &&
+	grep "cannot force update the branch '\''wt-2'\'' checked out at.*wt-2" err
 '
 
 test_expect_success !SANITIZE_LEAK 'refuse to fetch over ref: checked out' '
@@ -77,24 +82,24 @@ test_expect_success !SANITIZE_LEAK 'refuse to fetch over ref: checked out' '
 '
 
 test_expect_success !SANITIZE_LEAK 'refuse to fetch over ref: worktree in bisect' '
-	test_when_finished rm -rf .git/worktrees/wt-*/BISECT_* &&
+	test_when_finished git -C wt-4 bisect reset &&
 
-	touch .git/worktrees/wt-4/BISECT_LOG &&
-	echo refs/heads/fake-2 >.git/worktrees/wt-4/BISECT_START &&
+	# Set up a bisect so HEAD no longer points to wt-4.
+	git -C wt-4 bisect start &&
+	git -C wt-4 bisect bad wt-4 &&
+	git -C wt-4 bisect good wt-1 &&
 
-	test_must_fail git fetch server +refs/heads/fake-2:refs/heads/fake-2 2>err &&
+	test_must_fail git fetch server +refs/heads/wt-4:refs/heads/wt-4 2>err &&
 	grep "refusing to fetch into branch" err
 '
 
 test_expect_success !SANITIZE_LEAK 'refuse to fetch over ref: worktree in rebase' '
-	test_when_finished rm -rf .git/worktrees/wt-*/rebase-merge &&
+	test_when_finished git -C wt-3 rebase --abort &&
 
-	mkdir -p .git/worktrees/wt-4/rebase-merge &&
-	touch .git/worktrees/wt-4/rebase-merge/interactive &&
-	echo refs/heads/fake-1 >.git/worktrees/wt-4/rebase-merge/head-name &&
-	echo refs/heads/fake-2 >.git/worktrees/wt-4/rebase-merge/onto &&
+	# This will fail part-way through due to a conflict.
+	test_must_fail git -C wt-3 rebase conflict-3 &&
 
-	test_must_fail git fetch server +refs/heads/fake-1:refs/heads/fake-1 2>err &&
+	test_must_fail git fetch server +refs/heads/wt-3:refs/heads/wt-3 2>err &&
 	grep "refusing to fetch into branch" err
 '
 
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