Avoid regressions in clang nullability checks

Clang 15 (and still as of 16) lost the ability to understand null checks in
conditionals, which is supposed to suppress these warnings.  For now, work
around some, and suppress others.

The suppression boilerplate here is noisy and ugly, and hopefully temporary.
It should be removed once the issue is fixed in clang.

See https://github.com/llvm/llvm-project/issues/63018

1 files changed, 15 insertions, 1 deletions

diff --git a/src/writer.c b/src/writer.c
index 2a6d7c31..bdcb8e8e 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -8,6 +8,7 @@
 #include "string_utils.h"
 #include "try.h"
 #include "uri_utils.h"
+#include "warnings.h"
 
 #include "serd/serd.h"
 
@@ -762,7 +763,9 @@ write_uri_node(SerdWriter* const writer,
     SerdURI uri;
     SerdURI abs_uri;
     serd_env_get_base_uri(writer->env, &in_base_uri);
+    SERD_DISABLE_NULL_WARNINGS
     serd_uri_parse(node->buf, &uri);
+    SERD_RESTORE_WARNINGS
     serd_uri_resolve(&uri, &in_base_uri, &abs_uri);
     bool           rooted = uri_is_under(&writer->base_uri, &writer->root_uri);
     SerdURI*       root   = rooted ? &writer->root_uri : &writer->base_uri;
@@ -976,6 +979,8 @@ serd_writer_write_statement(SerdWriter*        writer,
     return SERD_SUCCESS;
   }
 
+  SERD_DISABLE_NULL_WARNINGS
+
   // Separate graphs if necessary
   if ((graph && !serd_node_equals(graph, &writer->context.graph)) ||
       (!graph && writer->context.graph.type)) {
@@ -989,6 +994,8 @@ serd_writer_write_statement(SerdWriter*        writer,
     }
   }
 
+  SERD_RESTORE_WARNINGS
+
   if ((flags & SERD_LIST_CONT)) {
     // Continue a list
     if (!strcmp((const char*)predicate->buf, NS_RDF "first") &&
@@ -1106,11 +1113,14 @@ serd_writer_end_anon(SerdWriter* writer, const SerdNode* node)
   TRY(st, write_sep(writer, SEP_ANON_END));
   pop_context(writer);
 
-  if (serd_node_equals(node, &writer->context.subject)) {
+  SERD_DISABLE_NULL_WARNINGS
+
+  if (node && serd_node_equals(node, &writer->context.subject)) {
     // Now-finished anonymous node is the new subject with no other context
     writer->context.predicate.type = SERD_NOTHING;
   }
 
+  SERD_RESTORE_WARNINGS
   return st;
 }
 
@@ -1201,7 +1211,9 @@ serd_writer_set_root_uri(SerdWriter* writer, const SerdNode* uri)
 
   if (uri && uri->buf) {
     writer->root_node = serd_node_copy(uri);
+    SERD_DISABLE_NULL_WARNINGS
     serd_uri_parse(uri->buf, &writer->root_uri);
+    SERD_RESTORE_WARNINGS
   } else {
     writer->root_node = SERD_NODE_NULL;
     writer->root_uri  = SERD_URI_NULL;
@@ -1240,7 +1252,9 @@ serd_writer_free(SerdWriter* writer)
     return;
   }
 
+  SERD_DISABLE_NULL_WARNINGS
   serd_writer_finish(writer);
+  SERD_RESTORE_WARNINGS
   free_context(&writer->context);
   free_anon_stack(writer);
   serd_stack_free(&writer->anon_stack);