On Tue, Jul 07, 2026 at 12:55:31PM -0700, Junio C Hamano wrote:

Patrick Steinhardt [off-list ref] writes:

quoted

diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index d7f82e1bec..1212b306b6 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh

@@ -740,6 +740,127 @@ test_expect_success 'geometric repacking honors configured split factor' '
 	)
 '
 
+test_expect_success 'pre-auto-gc hook runs exactly once' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		write_script .git/hooks/pre-auto-gc <<-\EOF &&
+		echo hook >>hook.log
+		EOF
+
+		# Satisfy the auto condition for multiple tasks, both in the
+		# foreground and in the background phase.
+		git config set maintenance.reflog-expire.auto -1 &&
+		git config set maintenance.geometric-repack.auto -1 &&
+		git config set maintenance.rerere-gc.auto -1 &&
+
+		GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+			git maintenance run --auto 2>/dev/null &&
+
+		# The successful hook does not inhibit any of the tasks...
+		test_subcommand git reflog expire --all <trace2.txt &&
+		test_subcommand_flex git repack <trace2.txt &&
+		test_subcommand git rerere gc <trace2.txt &&
+		# ... but it must only have been executed a single time.
+		test_line_count = 1 hook.log
+	)
+'

Somehow I'd feel better if the hook used a full path to the append
only log file, but it is reasonably clear that these three commands
are unlikely to chdir around, so it may be OK.

Obviously not in scope of this topic, but I wonder if we have a
better way to test these three "housekeeping tasks" have run, than
casting in stone the current implementation that spawns these three
external command as subprocesses.

Yeah, this is awfully fragile indeed. Since 25914c4fde (maintenance: add
trace2 regions for task execution, 2020-09-17) we already have trace2
markers for each task that's running, so that may indeed be a much
better way to figure out whether the task is running or not.

I've made some local changes, but will hold back with sending a v2 until
there's more feedback.

Thanks!

Patrick