Add assertions for all non-null pointers in the public API

Clang issues warnings at build time based on the SERD_NONNULL annotations,
which is a much better approach in general.  However, it does not cover cases
where the API is being used with another compiler, or without a compiler that
can statically check things at all (such as Python or other dynamic language
bindings).

In those situations, getting a clear assertion message is a lot less confusing
than a random crash somewhere in serd, and it makes it clear that the bug is in
the caller, so I think it's worth the tedious verbosity.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/world.c b/src/world.c
index 58efac90..39eeaec3 100644
--- a/src/world.c
+++ b/src/world.c
@@ -24,6 +24,7 @@
 #  include <unistd.h>
 #endif
 
+#include <assert.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -110,12 +111,15 @@ serd_world_free(SerdWorld* const world)
 SerdNodes*
 serd_world_nodes(SerdWorld* const world)
 {
+  assert(world);
   return world->nodes;
 }
 
 const SerdNode*
 serd_world_get_blank(SerdWorld* const world)
 {
+  assert(world);
+
   char* buf = world->blank.string;
   memset(buf, 0, BLANK_CHARS + 1);