t5304: use "reflog expire --all" to clear the reflog

This test checks that unreachable objects are really removed. For the test to
work, it has to ensure that no reflog retain any reachable objects.

Previously, it did this by manipulating the file system to remove reflog in the
first test, and relying on git not updating the reflog if the relevant logfile
doesn't exist in follow-up tests.

Now, explicitly clear the reflog using 'reflog expire'. This reduces the
dependency between test functions. It also is more amenable to use with
reftable, which has no concept of (non)-existence of a reflog

Signed-off-by: Han-Wen Nienhuys <[email protected]>
Reviewed-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: hanwen

t/t5304-prune.sh

@@ -81,29 +81,28 @@ test_expect_success 'prune: prune nonsense parameters' '
 
 test_expect_success 'prune: prune unreachable heads' '
 	git config core.logAllRefUpdates false &&
-	mv .git/logs .git/logs.old &&
-	: > file2 &&
+	>file2 &&
 	git add file2 &&
 	git commit -m temporary &&
 	tmp_head=$(git rev-list -1 HEAD) &&
 	git reset HEAD^ &&
+	git reflog expire --all &&
 	git prune &&
 	test_must_fail git reset $tmp_head --
 '
 
 test_expect_success 'prune: do not prune detached HEAD with no reflog' '
 	git checkout --detach --quiet &&
 	git commit --allow-empty -m "detached commit" &&
-	# verify that there is no reflogs
-	# (should be removed and disabled by previous test)
-	test_path_is_missing .git/logs &&
+	git reflog expire --all &&
 	git prune -n >prune_actual &&
 	test_must_be_empty prune_actual
 '
 
 test_expect_success 'prune: prune former HEAD after checking out branch' '
 	head_oid=$(git rev-parse HEAD) &&
 	git checkout --quiet main &&
+	git reflog expire --all &&
 	git prune -v >prune_actual &&
 	grep "$head_oid" prune_actual
 '