chore: import upstream snapshot with attribution

test/fuzz/fuzz_pipeline_loads.py

@@ -0,0 +1,46 @@
+# SPDX-FileCopyrightText: 2022-present deepset GmbH <info@deepset.ai>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""Fuzz target for ``Pipeline.loads`` — deserializing untrusted serialized pipelines.
+
+Loading a serialized pipeline is an explicit attack surface (see SECURITY.md), so this
+target feeds arbitrary fuzzer bytes through the YAML unmarshaller and ``from_dict``.
+"""
+
+import sys
+
+import atheris
+
+with atheris.instrument_imports():
+    from haystack import Pipeline
+    from haystack.core.errors import DeserializationError, PipelineError
+
+# Exceptions that are a normal reaction to malformed input. Anything else — a crash,
+# unbounded recursion, a hang, or an unexpected exception type — is a genuine finding.
+_EXPECTED = (DeserializationError, PipelineError, ValueError, TypeError, KeyError)
+
+# Known finding, deferred to a separate fix: non-dict YAML documents (e.g. an empty
+# string, a bare scalar, or a list) unmarshal cleanly and then make ``from_dict`` raise
+# a raw ``AttributeError`` from ``data.get(...)`` instead of a ``DeserializationError``.
+# Tolerated here so the target builds and fuzzes; remove once ``from_dict`` validates
+# its input type and this collapses back into ``DeserializationError``.
+_KNOWN_BUGS = (AttributeError,)
+
+
+def TestOneInput(data: bytes) -> None:
+    """Feed one fuzzer-generated input to ``Pipeline.loads`` as a YAML document."""
+    try:
+        Pipeline.loads(data)
+    except _EXPECTED + _KNOWN_BUGS:
+        pass
+
+
+def main() -> None:
+    """Set up and run the Atheris fuzzing loop."""
+    atheris.Setup(sys.argv, TestOneInput)
+    atheris.Fuzz()
+
+
+if __name__ == "__main__":
+    main()