Fix items' instance path as well.

Author: Julian

jsonschema/_validators.py

@@ -1,5 +1,4 @@
 from fractions import Fraction
-from itertools import islice
 from urllib.parse import urldefrag, urljoin
 import re
 
@@ -72,8 +71,12 @@ def items(validator, items, instance, schema):
         message = f"Expected at most {prefix} items, but found {len(instance)}"
         yield ValidationError(message)
     else:
-        for item in islice(instance, prefix, None):
-            yield from validator.descend(instance=item, schema=items)
+        for index in range(prefix, len(instance)):
+            yield from validator.descend(
+                instance=instance[index],
+                schema=items,
+                path=index,
+            )
 
 
 def additionalItems(validator, aI, instance, schema):

jsonschema/tests/test_validators.py

@@ -1163,6 +1163,58 @@ def test_prefixItems(self):
             ),
         )
 
+    def test_prefixItems_with_items(self):
+        schema = {
+            "items": {"type": "string"},
+            "prefixItems": [{}],
+        }
+        validator = validators.Draft202012Validator(schema)
+        e1, e2 = validator.iter_errors(["foo", 2, "bar", 4, "baz"])
+        self.assertEqual(
+            (
+                e1.message,
+                e1.validator,
+                e1.validator_value,
+                e1.instance,
+                e1.absolute_path,
+                e1.schema,
+                e1.schema_path,
+                e1.json_path,
+            ),
+            (
+                "2 is not of type 'string'",
+                "type",
+                "string",
+                2,
+                deque([1]),
+                {"type": "string"},
+                deque(["items", "type"]),
+                "$[1]",
+            ),
+        )
+        self.assertEqual(
+            (
+                e2.message,
+                e2.validator,
+                e2.validator_value,
+                e2.instance,
+                e2.absolute_path,
+                e2.schema,
+                e2.schema_path,
+                e2.json_path,
+            ),
+            (
+                "4 is not of type 'string'",
+                "type",
+                "string",
+                4,
+                deque([3]),
+                {"type": "string"},
+                deque(["items", "type"]),
+                "$[3]",
+            ),
+        )
+
 
 class MetaSchemaTestsMixin(object):
     # TODO: These all belong upstream