scalar unregister: stop FSMonitor daemon

Especially on Windows, we will need to stop that daemon, just in case
that the directory needs to be removed (the daemon would otherwise hold
a handle to that directory, preventing it from being deleted).

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/scalar/scalar.c

@@ -244,6 +244,16 @@ static int start_fsmonitor_daemon(void)
 	return 0;
 }
 
+static int stop_fsmonitor_daemon(void)
+{
+	assert(have_fsmonitor_support());
+
+	if (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING)
+		return run_git("fsmonitor--daemon", "stop", NULL);
+
+	return 0;
+}
+
 static int register_dir(void)
 {
 	if (add_or_remove_enlistment(1))
@@ -468,6 +478,9 @@ static int delete_enlistment(struct strbuf *enlistment)
 	strbuf_release(&parent);
 #endif
 
+	if (have_fsmonitor_support() && stop_fsmonitor_daemon())
+		return error(_("failed to stop the FSMonitor daemon"));
+
 	if (remove_dir_recursively(enlistment, 0))
 		return error(_("failed to delete enlistment directory"));