Refactor TruncateError handling for better readability

Keep TruncateError in the error tuple but check for it specifically
within the block to avoid retry logic. This makes it clearer that
TruncateError is similar to other request errors but requires
different handling.

Co-authored-by: mykaul <4655593+mykaul@users.noreply.github.com>

Author: Copilot

cassandra/cluster.py

@@ -5257,21 +5257,18 @@ def _set_result(self, host, connection, pool, response):
                         self.query, retry_num=self._query_retries, **response.info)
                 elif isinstance(response, (OverloadedErrorMessage,
                                            IsBootstrappingErrorMessage,
-                                           ServerError)):
+                                           TruncateError, ServerError)):
                     log.warning("Host %s error: %s.", host, response.summary)
                     if self._metrics is not None:
                         self._metrics.on_other_error()
+                    # TruncateError should not be retried as it indicates a permanent failure
+                    if isinstance(response, TruncateError):
+                        self._set_final_exception(response.to_exception())
+                        return
                     cl = getattr(self.message, 'consistency_level', None)
                     retry = retry_policy.on_request_error(
                         self.query, cl, error=response,
                         retry_num=self._query_retries)
-                elif isinstance(response, TruncateError):
-                    # TruncateError should not be retried as it indicates a permanent failure
-                    log.warning("Host %s truncate error: %s.", host, response.summary)
-                    if self._metrics is not None:
-                        self._metrics.on_other_error()
-                    self._set_final_exception(response.to_exception())
-                    return
                 elif isinstance(response, PreparedQueryNotFound):
                     if self.prepared_statement:
                         query_id = self.prepared_statement.query_id