fix: guard malformed JSON in JSONConverter content_key path (#11980)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: David S. Batista <dsbatista@gmail.com>

Author: 3 people

haystack/components/converters/json.py

@@ -211,7 +211,15 @@ def _get_content_and_meta(self, source: ByteStream) -> list[tuple[str, dict[str,
         else:
             # We just load the whole file as JSON if the user didn't provide a jq filter.
             # We put it in a list even if it's not to ease handling it later on.
-            objects = [json.loads(file_content)]
+            try:
+                objects = [json.loads(file_content)]
+            except json.JSONDecodeError as exc:
+                logger.warning(
+                    "Failed to extract text from {source}. Skipping it. Error: {error}",
+                    source=source.meta["file_path"],
+                    error=exc,
+                )
+                return []
 
         result = []
         if self._content_key is not None:

releasenotes/notes/fix-json-converter-content-key-malformed-8a7abe0d43e5355c.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Fixed ``JSONConverter`` crashing on a malformed JSON source when it is
+    configured with ``content_key`` and no ``jq_schema``. The non-jq branch
+    called ``json.loads`` without a guard, so a single invalid ``.json`` file
+    raised an unhandled ``JSONDecodeError`` and aborted the whole run. Invalid
+    JSON is now caught, logged, and skipped, matching the behavior of the
+    ``jq_schema`` path.

test/components/converters/test_json.py

@@ -258,6 +258,23 @@ def test_run_with_bad_encoding(tmpdir, caplog):
     assert result == {"documents": []}
 
 
+def test_run_with_malformed_json_and_content_key(tmpdir, caplog):
+    test_file = Path(tmpdir / "test_file.json")
+    test_file.write_text("This is not valid JSON.", "utf-8")
+
+    sources = [test_file]
+    converter = JSONConverter(content_key="motivation")
+
+    caplog.clear()
+    with caplog.at_level(logging.WARNING):
+        result = converter.run(sources=sources)
+
+    records = caplog.records
+    assert len(records) == 1
+    assert records[0].msg.startswith(f"Failed to extract text from {test_file}. Skipping it. Error:")
+    assert result == {"documents": []}
+
+
 def test_run_with_single_meta(tmpdir):
     first_test_file = Path(tmpdir / "first_test_file.json")
     second_test_file = Path(tmpdir / "second_test_file.json")