migration/cpr: Document obscure usage of g_autofree when parse str

HMP parsing of cpr_exec_command contains an obscure usage of g_autofree.
Provide a document for it to be clear that it's intentional, rather than
memory leaked.

Cc: Dr. David Alan Gilbert <dave@treblig.org>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Dr. David Alan Gilbert <dave@treblig.org>
Link: https://lore.kernel.org/r/20251023161657.2821652-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>

diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index 847d18faaacd0aafff4353d19bc1ce193bd026c3..79426bf5d7e4735b53fc6ffdd34361fef64e101d 100644 (file)
--- a/migration/migration-hmp-cmds.c
+++ b/migration/migration-hmp-cmds.c
@@ -734,6 +734,12 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
         visit_type_bool(v, param, &p->direct_io, &err);
         break;
     case MIGRATION_PARAMETER_CPR_EXEC_COMMAND: {
+        /*
+         * NOTE: g_autofree will only auto g_free() the strv array when
+         * needed, it will not free the strings within the array. It's
+         * intentional: when strv is set, the ownership of the strings will
+         * always be passed to p->cpr_exec_command via QAPI_LIST_APPEND().
+         */
         g_autofree char **strv = NULL;
         g_autoptr(GError) gerr = NULL;
         strList **tail = &p->cpr_exec_command;