* fixes in f2b_{mod}_destroy()

src/backend.c

@@ -100,7 +100,7 @@ f2b_backend_init(f2b_backend_t *backend, f2b_config_section_t *config) {
 
 void
 f2b_backend_destroy(f2b_backend_t *backend) {
-  assert(backend != NULL);
+  if (!backend) return;
   backend->destroy(backend->cfg);
   dlclose(backend->h);
   free(backend);

src/filter.c

@@ -159,7 +159,7 @@ f2b_filter_init(f2b_filter_t *filter, f2b_config_section_t *config) {
 
 void
 f2b_filter_destroy(f2b_filter_t *filter) {
-  assert(filter != NULL);
+  if (!filter) return;
   filter->destroy(filter->cfg);
   dlclose(filter->h);
   free(filter);

src/source.c

@@ -96,7 +96,7 @@ f2b_source_init(f2b_source_t *source, f2b_config_section_t *config) {
 
 void
 f2b_source_destroy(f2b_source_t *source) {
-  assert(source != NULL);
+  if (!source) return;
   source->destroy(source->cfg);
   dlclose(source->h);
   free(source);