Properly set the failing validator for min/maxContains.

Also check that only one error is raised for maxContains,
which is the case right now due to short circuiting as
soon as we see too many matches.

Author: Julian

jsonschema/_validators.py

@@ -118,6 +118,8 @@ def contains(validator, contains, instance, schema):
                 yield ValidationError(
                     "Too many items match the given schema "
                     f"(expected at most {max_contains})",
+                    validator="maxContains",
+                    validator_value=max_contains,
                 )
                 return
 
@@ -131,6 +133,8 @@ def contains(validator, contains, instance, schema):
             yield ValidationError(
                 "Too few items match the given schema (expected at least "
                 f"{min_contains} but only {matches} matched)",
+                validator="minContains",
+                validator_value=min_contains,
             )
 
 

jsonschema/tests/test_validators.py

@@ -1221,6 +1221,94 @@ def test_prefixItems_with_items(self):
             ),
         )
 
+    def test_contains_too_many(self):
+        """
+        `contains` + `maxContains` produces only one error, even if there are
+        many more incorrectly matching elements.
+        """
+        schema = {"contains": {"type": "string"}, "maxContains": 2}
+        validator = validators.Draft202012Validator(schema)
+        error, = validator.iter_errors(["foo", 2, "bar", 4, "baz", "quux"])
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.absolute_path,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                "Too many items match the given schema (expected at most 2)",
+                "maxContains",
+                2,
+                ["foo", 2, "bar", 4, "baz", "quux"],
+                deque([]),
+                {"contains": {"type": "string"}, "maxContains": 2},
+                deque(["contains"]),
+                "$",
+            ),
+        )
+
+    def test_contains_too_few(self):
+        schema = {"contains": {"type": "string"}, "minContains": 2}
+        validator = validators.Draft202012Validator(schema)
+        error, = validator.iter_errors(["foo", 2, 4])
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.absolute_path,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                (
+                    "Too few items match the given schema "
+                    "(expected at least 2 but only 1 matched)"
+                ),
+                "minContains",
+                2,
+                ["foo", 2, 4],
+                deque([]),
+                {"contains": {"type": "string"}, "minContains": 2},
+                deque(["contains"]),
+                "$",
+            ),
+        )
+
+    def test_contains_none(self):
+        schema = {"contains": {"type": "string"}, "minContains": 2}
+        validator = validators.Draft202012Validator(schema)
+        error, = validator.iter_errors([2, 4])
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.absolute_path,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                "[2, 4] does not contain items matching the given schema",
+                "contains",
+                {"type": "string"},
+                [2, 4],
+                deque([]),
+                {"contains": {"type": "string"}, "minContains": 2},
+                deque(["contains"]),
+                "$",
+            ),
+        )
+
 
 class MetaSchemaTestsMixin(object):
     # TODO: These all belong upstream