Fix relative refs in handler-loaded schemas

fastjsonschema/ref_resolver.py

@@ -163,7 +163,7 @@ def _ensure_walked(self, uri, schema):
         normalized = normalize(uri) if uri else ''
         if normalized in self._walked_uris:
             return
-        self.walk(schema)
+        self.walk(schema, rewrite_refs=False)
         self._walked_uris.add(normalized)
 
     def get_uri(self):
@@ -178,7 +178,7 @@ def get_scope_name(self):
         name = name.lower().rstrip('_')
         return name
 
-    def walk(self, node: dict, depth=0):
+    def walk(self, node: dict, depth=0, rewrite_refs=True):
         """
         Walk thru schema and dereferencing ``id`` and ``$ref`` instances
         """
@@ -190,15 +190,16 @@ def walk(self, node: dict, depth=0):
         if isinstance(node, bool):
             pass
         elif '$ref' in node and isinstance(node['$ref'], str):
-            ref = node['$ref']
-            node['$ref'] = urlparse.urljoin(self.resolution_scope, ref)
+            if rewrite_refs:
+                ref = node['$ref']
+                node['$ref'] = urlparse.urljoin(self.resolution_scope, ref)
         elif ('$id' in node or 'id' in node) and isinstance(get_id(node), str):
             with self.in_scope(get_id(node)):
                 self.store[normalize(self.resolution_scope)] = node
                 for _, item in node.items():
                     if isinstance(item, dict):
-                        self.walk(item, depth + 1)
+                        self.walk(item, depth + 1, rewrite_refs)
         else:
             for _, item in node.items():
                 if isinstance(item, dict):
-                    self.walk(item, depth + 1)
+                    self.walk(item, depth + 1, rewrite_refs)

tests/test_integration.py

@@ -146,3 +146,24 @@ def test_swap_handlers():
     }
     validator2 = compile({"$ref": "sch://schema"}, handlers={"sch": repo2.__getitem__})
     assert validator2("hello world") is not None
+
+
+def test_relative_ref_in_remote_schema_is_resolved_once():
+    repo = {
+        'schemas/main.json': {
+            'definitions': {
+                'object': {
+                    'type': 'object',
+                    'properties': {'value': {'$ref': 'main.json#/definitions/string'}},
+                },
+                'string': {'type': 'string'},
+            },
+        },
+    }
+
+    validator = compile(
+        {'$ref': 'schemas/main.json#/definitions/object'},
+        handlers={'': repo.__getitem__},
+    )
+
+    assert validator({'value': 'ok'}) == {'value': 'ok'}