Fix field validation on Base64Bytes and Base64Str

pydantic/types.py

@@ -2344,9 +2344,11 @@ def __get_pydantic_json_schema__(
         return field_schema
 
     def __get_pydantic_core_schema__(self, source: type[Any], handler: GetCoreSchemaHandler) -> core_schema.CoreSchema:
+        base_schema: Any = handler(source)
+        del base_schema['type']
         return core_schema.with_info_after_validator_function(
             function=self.decode,
-            schema=core_schema.bytes_schema(),
+            schema=core_schema.bytes_schema(**base_schema),
             serialization=core_schema.plain_serializer_function_ser_schema(function=self.encode),
         )
 

tests/test_types.py

@@ -5508,6 +5508,42 @@ class Model(BaseModel):
     }
 
 
+def test_base64_with_valid_min_length() -> None:
+    class Model(BaseModel):
+        base64_value: Base64Bytes = Field(min_length=3)
+
+    value = b'Zm9v'
+    m = Model.model_construct(base64_value=value)
+    assert m.base64_value == value
+    assert Model.model_json_schema() == {
+        'properties': {
+            'base64_value': {
+                'format': 'base64',
+                'minLength': 3,
+                'title': 'Base64 Value',
+                'type': 'string',
+            }
+        },
+        'required': ['base64_value'],
+        'title': 'Model',
+        'type': 'object',
+    }
+
+
+def test_base64_with_invalid_min_length() -> None:
+    """Check that an error is raised when the length of the base64
+    value is less or more than the min_length and max_length"""
+
+    class Model(BaseModel):
+        base64_value: Base64Bytes = Field(min_length=3, max_length=5)
+
+    with pytest.raises(ValidationError):
+        Model(**{'base64_value': b''})
+
+    with pytest.raises(ValidationError):
+        Model(**{'base64_value': b'123456'})
+
+
 @pytest.mark.parametrize(
     ('field_type', 'input_data'),
     [