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Fix UNPREPARED handling in ResponseFuture to allow recovery on query ID mismatch #726

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Fix UNPREPARED handling in ResponseFuture to allow recovery on query ID mismatch #726

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42e844a
Initial plan
Copilot Mar 4, 2026
a957d3f
Fix hexlify log format and add regression test docstring for Prepared…
Copilot Mar 4, 2026
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9 changes: 7 additions & 2 deletions cassandra/cluster.py
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Original file line number Diff line number Diff line change
Expand Up @@ -4724,13 +4724,18 @@ def _set_result(self, host, connection, pool, response):
self.prepared_statement = self.session.cluster._prepared_statements[query_id]
except KeyError:
if not self.prepared_statement:
log.error("Tried to execute unknown prepared statement: id=%s", hexlify(query_id))
log.error(
"Tried to execute unknown prepared statement: id=%s",
hexlify(query_id).decode('ascii'),
)
self._set_final_exception(response)
return
log.warning(
"UNPREPARED for query id %s while executing statement id %s. "
"Could not resolve returned id in cache, proceeding with in-flight context.",
hexlify(query_id), hexlify(self.prepared_statement.query_id))
hexlify(query_id).decode('ascii'),
hexlify(self.prepared_statement.query_id).decode('ascii'),
)

current_keyspace = self._connection.keyspace
prepared_keyspace = self.prepared_statement.keyspace
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8 changes: 7 additions & 1 deletion tests/unit/test_response_future.py
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Original file line number Diff line number Diff line change
Expand Up @@ -622,6 +622,12 @@ def test_prepared_query_not_found_bad_keyspace(self):
rf.result()

def test_prepared_query_not_found_uses_local_prepared_context(self):
"""
Regression test: the original code asserted response.info == self.prepared_statement.query_id,
which raised AssertionError when the server returned a different query id (e.g. due to a
coordinator race or restart), preventing recovery. The fix removes the assertion and falls
back to the in-flight prepared_statement context so reprepare can still proceed.
"""
session = self.make_session()
pool = session._pools.get.return_value
connection = Mock(spec=Connection)
Expand All @@ -639,7 +645,7 @@ def test_prepared_query_not_found_uses_local_prepared_context(self):
rf.prepared_statement.query_string = "SELECT * FROM foobar"
rf.prepared_statement.keyspace = "FooKeyspace"

# Different query id in UNPREPARED response should not prevent reprepare when local context exists.
# Server returns a *different* query id in UNPREPARED — old code would raise AssertionError here.
result = Mock(spec=PreparedQueryNotFound, info=b"other-query-id")
rf._set_result(None, None, None, result)

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