fix: handle non-dict parsed JSON in firmware version manifest parser

parse_versioning kept the last json.loads-parseable line and then indexed it
with a string key. When that line parsed to a non-dict (e.g. a JSON array),
the index raised an uncaught TypeError because only KeyError was handled,
aborting the task. Guard that the parsed value is a dict before indexing and
fall through to the existing 'no JSON could be loaded' path otherwise. Adds a
regression test covering the non-dict input case.

Author: dholt

roles/nvidia-dgx-firmware/files/parse_manifest.py

@@ -173,6 +173,11 @@ def return_json(payload):
             manifest_json = json.loads(line)
         except ValueError:
             pass
+
+    if not isinstance(manifest_json, dict):
+        print('No JSON could be loaded, is the container already running?')
+        exit(1)
+
     try:
         if manifest_json['ErrorWritingVersioning']:
             print('No JSON could be loaded, is the container already running?')

roles/nvidia-dgx-firmware/tests/test_parse_manifest.py

@@ -0,0 +1,34 @@
+import subprocess
+import sys
+import tempfile
+import unittest
+
+from pathlib import Path
+
+
+SCRIPT = Path(__file__).resolve().parents[1] / 'files' / 'parse_manifest.py'
+
+
+class ParseManifestTest(unittest.TestCase):
+    def test_parse_versioning_rejects_non_dict_json(self):
+        with tempfile.TemporaryDirectory() as temp_dir:
+            manifest = Path(temp_dir) / 'versioning.json'
+            manifest.write_text('[1,2,3]\n')
+
+            result = subprocess.run(
+                [sys.executable, str(SCRIPT), 'parse_versioning', str(manifest)],
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+                universal_newlines=True,
+            )
+
+        self.assertEqual(result.returncode, 1)
+        self.assertEqual(
+            result.stdout,
+            'No JSON could be loaded, is the container already running?\n',
+        )
+        self.assertEqual(result.stderr, '')
+
+
+if __name__ == '__main__':
+    unittest.main()