From 30221d4de4097a91f33c7a1c23290db78f392726 Mon Sep 17 00:00:00 2001
From: Matt Faltyn <faltyn.matthew@gmail.com>
Date: Sun, 26 Jul 2026 20:34:42 +0200
Subject: [PATCH] fix(validation): report schema errors for invalid YAML

Signed-off-by: Matt Faltyn <faltyn.matthew@gmail.com>
---
 validation/test_validate.py | 61 +++++++++++++++++++++++++++++++++++++
 validation/validate.py      |  9 +++---
 2 files changed, 65 insertions(+), 5 deletions(-)
 create mode 100644 validation/test_validate.py

diff --git a/validation/test_validate.py b/validation/test_validate.py
new file mode 100644
index 00000000..0a646037
--- /dev/null
+++ b/validation/test_validate.py
@@ -0,0 +1,61 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+import io
+import sys
+import tempfile
+import unittest
+from contextlib import redirect_stdout
+from pathlib import Path
+from unittest.mock import patch
+
+from validation import validate
+
+
+class ValidateCliTest(unittest.TestCase):
+    def test_schema_invalid_documents_report_errors(self) -> None:
+        schema_path = Path(__file__).parents[1] / "core-spec" / "osi-schema.json"
+
+        cases = (
+            ("", "(root)"),
+            ("[]\n", "(root)"),
+            ("scalar\n", "(root)"),
+            ("semantic_model: invalid\n", "semantic_model"),
+        )
+        for content, error_path in cases:
+            with self.subTest(content=content), tempfile.TemporaryDirectory() as tmpdir:
+                yaml_path = Path(tmpdir) / "model.yaml"
+                yaml_path.write_text(content, encoding="utf-8")
+                stdout = io.StringIO()
+
+                with (
+                    patch.object(
+                        sys,
+                        "argv",
+                        ["validate.py", str(yaml_path), "--schema", str(schema_path)],
+                    ),
+                    redirect_stdout(stdout),
+                    self.assertRaises(SystemExit) as raised,
+                ):
+                    validate.main()
+
+                self.assertEqual(raised.exception.code, 1)
+                self.assertIn(f"[Schema] {error_path}:", stdout.getvalue())
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/validation/validate.py b/validation/validate.py
index 258d34f1..bd73e5cb 100644
--- a/validation/validate.py
+++ b/validation/validate.py
@@ -75,7 +75,7 @@
 SKIP_SQL_VALIDATION = {"MDX", "TABLEAU", "MAQL"}
 
 
-def validate_schema(data: dict, schema: dict) -> list[str]:
+def validate_schema(data: object, schema: dict) -> list[str]:
     """Validate against JSON Schema."""
     validator = Draft202012Validator(schema)
     errors = []
@@ -255,11 +255,10 @@ def main():
             sys.exit(1)
 
     # Run validations
-    errors = []
-    errors.extend(validate_schema(data, schema))
+    errors = validate_schema(data, schema)
 
-    # Run semantic-model-specific checks only for semantic model payloads.
-    if data.get("semantic_model"):
+    # Semantic checks assume the schema has established the nested data shapes.
+    if not errors and isinstance(data, dict) and data.get("semantic_model"):
         errors.extend(validate_unique_names(data))
         errors.extend(validate_references(data))
         errors.extend(validate_sql(data))