Guard semantic checks for invalid manifests

tests/test_schema_semantic_gate.py

@@ -0,0 +1,98 @@
+"""Schema-invalid synthetic manifests must not crash semantic validation."""
+
+from __future__ import annotations
+
+import io
+import json
+import sys
+import tempfile
+import unittest
+from contextlib import redirect_stdout
+from pathlib import Path
+from unittest import mock
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+try:
+    import validate_schemas
+except ImportError as exc:
+    validate_schemas = None
+    IMPORT_ERROR = str(exc)
+else:
+    IMPORT_ERROR = ""
+
+
+@unittest.skipIf(validate_schemas is None, f"validate_schemas unavailable: {IMPORT_ERROR}")
+class SemanticManifestValidation(unittest.TestCase):
+    def test_invalid_synthetic_manifest_reports_schema_errors_without_crashing(self):
+        with tempfile.TemporaryDirectory(dir=REPO_ROOT) as directory:
+            root = Path(directory)
+            (root / "emulators").mkdir()
+            platforms = root / "platforms"
+            platforms.mkdir()
+            (platforms / "_data_dirs.yml").write_text(
+                "data_directories: {}\n", encoding="utf-8"
+            )
+            (root / "database.json").write_text(
+                json.dumps({"files": None}), encoding="utf-8"
+            )
+            install = root / "install"
+            install.mkdir()
+            (install / "synthetic.json").write_text(
+                json.dumps({"files": None}), encoding="utf-8"
+            )
+            api = root / "docs" / "api" / "v1"
+            api.mkdir(parents=True)
+            (api / "catalog.json").write_text(
+                json.dumps({"count": 1, "items": None}), encoding="utf-8"
+            )
+
+            output = io.StringIO()
+            with mock.patch.object(validate_schemas, "ROOT", root), mock.patch.object(
+                sys, "argv", ["validate_schemas.py"]
+            ), redirect_stdout(output):
+                result = validate_schemas.main()
+
+        self.assertEqual(result, 1)
+        text = output.getvalue().replace("\\", "/")
+        self.assertIn("database.json", text)
+        self.assertIn("install/synthetic.json", text)
+        self.assertIn("docs/api/v1/catalog.json", text)
+        self.assertIn("files", text)
+        self.assertIn("items", text)
+        self.assertNotIn("Traceback", text)
+
+    def test_valid_synthetic_manifest_still_runs_semantic_checks(self):
+        manifest = {
+            "manifest_version": 2,
+            "source": "full",
+            "regions": [],
+            "platform": "synthetic",
+            "display_name": "Synthetic",
+            "version": "test",
+            "generated": "2026-10-21T00:00:00Z",
+            "base_destination": "",
+            "detect": [],
+            "standalone_copies": [],
+            "total_files": 1,
+            "total_size": 0,
+            "total_omitted": 0,
+            "omitted_files": [],
+            "files": [],
+        }
+        with tempfile.TemporaryDirectory(dir=REPO_ROOT) as directory:
+            path = Path(directory) / "synthetic.json"
+            path.write_text(json.dumps(manifest), encoding="utf-8")
+            errors = validate_schemas._validate_json_files(
+                [path],
+                "install-manifest.schema.json",
+                validate_schemas._semantic_install_checks,
+            )
+
+        self.assertEqual(len(errors), 1)
+        self.assertIn("total_files does not equal len(files)", errors[0])
+
+
+if __name__ == "__main__":
+    unittest.main()