core/exec-invoke: add a comment that acquire_home uses result from get_fixed_user

Prompted by https://github.com/systemd/systemd/pull/33016#discussion_r1614848067

diff --git a/src/core/exec-invoke.c b/src/core/exec-invoke.c
index e719976daa4fca45be64d83a839c6444cdbc48e7..ee62ff3dd42847c9c69777d5d0874cdf4d52c912 100644 (file)
--- a/src/core/exec-invoke.c
+++ b/src/core/exec-invoke.c
@@ -3594,7 +3594,7 @@ static int acquire_home(const ExecContext *c, const char **home, char **ret_buf)
 
         /* If WorkingDirectory=~ is set, try to acquire a usable home directory. */
 
-        if (*home)
+        if (*home) /* Already acquired from get_fixed_user()? */
                 return 0;
 
         if (!c->working_directory_home)