Merge pull request piccolo-orm#31 from piccolo-orm/relative_module_error

raise an error if a relative module is given for a ForeignKey references argument

Author: dantownsend

piccolo/table.py

@@ -200,6 +200,11 @@ def __init_subclass__(
                     references = cls
                 else:
                     if "." in references:
+                        # Don't allow relative modules - this may change in
+                        # the future.
+                        if references.startswith("."):
+                            raise ValueError("Relative imports aren't allowed")
+
                         module_path, table_class_name = references.rsplit(
                             ".", maxsplit=1
                         )

tests/columns/test_foreignkey.py

@@ -90,6 +90,22 @@ def tearDown(self):
         Manager.alter().drop_table().run_sync()
 
 
+class TestForeignKeyRelativeError(TestCase):
+    def test_foreign_key_relative_error(self):
+        """
+        Make sure that a references argument which contains a relative module
+        isn't allowed.
+        """
+        with self.assertRaises(ValueError) as manager:
+
+            class Band(Table):
+                manager = ForeignKey("..example_app.tables.Manager", null=True)
+
+        self.assertEqual(
+            manager.exception.__str__(), "Relative imports aren't allowed"
+        )
+
+
 class TestReferences(TestCase):
     def test_foreign_key_references(self):
         """