handler.c: Do not call free callback on failed payload

The free callback is meant to be executed whenever libweb fails to
execute something and let the user deallocate any pending memory.
However, the payload callback should deallocate user memory by itself on
failure, since relying on the free payload for this purpose is not
intuitive and fragile.

1 files changed, 3 insertions, 0 deletions

diff --git a/handler.c b/handler.c
index f30cfc3..455832b 100644
--- a/handler.c
+++ b/handler.c
@@ -75,6 +75,9 @@ static int on_payload(const struct http_payload *const p,
                 s->payload = r->step.payload;
                 c->args = r->args;
             }
+            else
+                /* Avoid calling r->free again on exit. */
+                *r = (const struct http_response){0};
 
             return ret;
         }