not calling schemas (#5641)

* not calling schemas * Update public/pathway/python/pathway/internals/schema.py Co-authored-by: Michał Bartoszkiewicz <[email protected]> * import --------- Co-authored-by: Michał Bartoszkiewicz <[email protected]> GitOrigin-RevId: 48b344f718a691fcb23fe0fd3a237e361e69131a
pathwaycom · Feb 8, 2024 · 1f40e26 · 1f40e26
1 parent 4c4c94b
commit 1f40e26
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diff --git a/python/pathway/internals/schema.py b/python/pathway/internals/schema.py
@@ -11,7 +11,7 @@
 from os import PathLike
 from pydoc import locate
 from types import MappingProxyType
-from typing import TYPE_CHECKING, Any, get_type_hints
+from typing import TYPE_CHECKING, Any, NoReturn, get_type_hints
 from warnings import warn
 
 import numpy as np
@@ -270,6 +270,11 @@ def __init__(self, *args, append_only: bool | None = None, **kwargs) -> None:
         }
         self.__types__ = {k: v.typehint for k, v in self.__dtypes__.items()}
 
+    def __call__(self) -> NoReturn:
+        raise TypeError(
+            "Schemas should not be called. Use `table.schema` not `table.schema()."
+        )
+
     def __or__(self, other: type[Schema]) -> type[Schema]:  # type: ignore
         return schema_add(self, other)  # type: ignore
 

diff --git a/python/pathway/tests/test_schema.py b/python/pathway/tests/test_schema.py
@@ -338,3 +338,13 @@ class D(pw.Schema, append_only=True):
         pass
 
     assert D.universe_properties.append_only is True
+
+
+def test_schemas_not_to_be_called():
+    with pytest.raises(TypeError):
+        pw.Table.empty().schema()
+
+
+def test_advanced_schemas_not_to_be_called():
+    with pytest.raises(TypeError):
+        (pw.Table.empty().schema | pw.Table.empty().schema)()