Root $ref does not work correctly

[oOLooCoreZOo]

Hi,

I found a crash due to infinite recursion while using local remote schemas.
I use following schemes:
MainSchema.schema.json:

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "$id": "MainSchema.schema.json",
    "$ref": "RemoteSchema.schema.json"
}

RemoteSchema.schema.json:

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "$id": "RemoteSchema.schema.json",
    "type": "object",
    "properties": {
        "street_address": { "type": "string" },
        "city": { "type": "string" },
        "state": { "type": "string" }
  },
  "required": ["street_address", "city", "state"]
}

You can probably get around this by using file:// in the $ref.
However, this is not needed if $ref is used in the properties entry.
I noticed that the function resolveThenPopulateSchema() and makeOrReuseSchema() handle refs different.
I copied the logic from makeOrReuseSchema() and at least in my case this fixed it.

diff --git a/ext/valijson-1.0.3/include/valijson/schema_parser.hpp b/ext/valijson-1.0.3/include/valijson/schema_parser.hpp
index fef97b3f5..40763d989 100644
--- a/ext/valijson-1.0.3/include/valijson/schema_parser.hpp
+++ b/ext/valijson-1.0.3/include/valijson/schema_parser.hpp
@@ -1013,23 +1013,44 @@ private:
         const std::string actualJsonPointer = sanitiseJsonPointer(
                 internal::json_reference::getJsonReferencePointer(jsonRef));

-        if (documentUri && (internal::uri::isUriAbsolute(*documentUri) || internal::uri::isUrn(*documentUri))) {
-            // Resolve reference against remote document
-            if (!fetchDoc) {
-                throwRuntimeError("Fetching of remote JSON References not enabled.");
-            }

-            const typename DocumentCache<AdapterType>::DocumentType *newDoc = fetchDoc(*documentUri);
+        // Determine the actual document URI based on the resolution
+        // scope. An absolute document URI will take precedence when
+        // present, otherwise we need to resolve the URI relative to
+        // the current resolution scope
+        const opt::optional<std::string> actualDocumentUri = resolveDocumentUri(currentScope, documentUri);

-            // Can't proceed without the remote document
-            if (!newDoc) {
-                throwRuntimeError("Failed to fetch referenced schema document: " + *documentUri);
-            }
+        if (actualDocumentUri && (!currentScope || *actualDocumentUri != *currentScope)) {
+            const typename FunctionPtrs<AdapterType>::DocumentType *newDoc = nullptr;
+
+            // Have we seen this document before?
+            typename DocumentCache<AdapterType>::Type::iterator docCacheItr =
+                    docCache.find(*actualDocumentUri);
+            if (docCacheItr == docCache.end()) {
+                // Resolve reference against remote document
+                if (!fetchDoc) {
+                    throwRuntimeError("Fetching of remote JSON References not enabled.");
+                }

-            // Add to document cache
-            typedef typename DocumentCache<AdapterType>::Type::value_type DocCacheValueType;
+                // Returns a pointer to the remote document that was
+                // retrieved, or null if retrieval failed. This class
+                // will take ownership of the pointer, and call freeDoc
+                // when it is no longer needed.
+                newDoc = fetchDoc(*actualDocumentUri);
+
+                // Can't proceed without the remote document
+                if (!newDoc) {
+                    throwRuntimeError("Failed to fetch referenced schema document: " + *actualDocumentUri);
+                }

-            docCache.insert(DocCacheValueType(*documentUri, newDoc));
+                typedef typename DocumentCache<AdapterType>::Type::value_type
+                        DocCacheValueType;
+
+                docCache.insert(DocCacheValueType(*actualDocumentUri, newDoc));
+
+            } else {
+                newDoc = docCacheItr->second;
+            }

             const AdapterType newRootNode(*newDoc);

Can you please check it?
Maybe it is a good idea to unify the behavior?

In addition to this, can you please add a new flag to disable the warning for the RAPIDJSON_ASSERT?

#warning "RAPIDJSON_ASSERT already defined."
#warning "Please include valijson/adapters/rapidjson_adapter.hpp before any RapidJSON headers."

I would like to use my own version. Is it even necessary?

Best regards,
Chris