{"record":{"id":"2b3c6e829673f035","repo":"warpdotdev/warp","slug":"truncated-tasks-for-forked-conversation-at-block-a","errorCode":null,"errorMessage":"Truncated tasks for forked conversation at block are empty for conversation {}.","messagePattern":"Truncated tasks for forked conversation at block are empty for conversation (.+?)\\.","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"app/src/ai/blocklist/history_model.rs","lineNumber":1854,"sourceCode":"                    if truncated_task.messages.is_empty() {\n                        return None;\n                    }\n                    if let Some(fork_point_exchange) = fork_point_exchange_by_task.get(t.id()) {\n                        reconcile_dangling_tool_calls_in_forked_task(\n                            &mut truncated_task,\n                            &source_task.messages,\n                            &fork_point_exchange.added_message_ids,\n                        );\n                    }\n                    Some(truncated_task)\n                } else {\n                    None\n                }\n            })\n            .collect();\n\n        if truncated_tasks.is_empty() {\n            return Err(anyhow!(\n                \"Truncated tasks for forked conversation at block are empty for conversation {}.\",\n                conversation.id()\n            ));\n        }\n\n        let updated_tasks_with_new_ids =\n            update_forked_task_properties(truncated_tasks, prefix, false, title_override);\n\n        let Some(sqlite_sender) = GlobalResourceHandlesProvider::as_ref(app)\n            .get()\n            .model_event_sender\n            .clone()\n        else {\n            return Err(anyhow!(\"No sqlite sender available.\"));\n        };\n\n        // We preserve reverted action IDs. Orphaned IDs (for actions not in fork) are harmless.\n        // The reverted states are only copied to the new conversation if the revert happened before the user clicked fork,","sourceCodeStart":1836,"sourceCodeEnd":1872,"githubUrl":"https://github.com/warpdotdev/warp/blob/e72fd7aacbbb2236d9b3be2aad7e7178fe94b4bc/app/src/ai/blocklist/history_model.rs#L1836-L1872","documentation":"In the fork-at-block flow of BlocklistAIHistoryModel, each existing task is truncated at the fork point (`truncated_task` computed per task, `None` when the task has nothing past/before the fork). If every task truncates to None — or the conversation has no tasks at all — `truncated_tasks` is empty and the model refuses to build the fork because there would be no content to persist or show.","triggerScenarios":"Calling fork-at-block on a conversation where no task's messages intersect the fork_point_exchange.added_message_ids: the chosen block precedes all task content, the exchange's message ids belong to no task, or the conversation's tasks have not been loaded/hydrated yet (cloud or DB fetch still in flight).","commonSituations":"Fork clicked on the very first block before any agent turn; forking a cloud conversation whose tasks are not yet hydrated locally; fork-point exchange id pointing at a system/placeholder exchange with no task messages.","solutions":["Verify the conversation actually has tasks loaded (hydrated from cloud/DB) before offering fork-at-block in the UI","Before calling, check that at least one task's messages intersect the fork exchange's added_message_ids","If tasks should exist, wait for hydration to complete and retry the fork","Surface a user-facing 'nothing to fork at this block' message instead of an internal anyhow error"],"exampleFix":"// before\nlet forked = model.fork_conversation_at_block(conv_id, exchange_id)?;\n\n// after: guard the precondition at the call site\nlet has_content = model\n    .conversation(&conv_id)\n    .map(|c| !c.tasks().is_empty())\n    .unwrap_or(false);\nanyhow::ensure!(has_content, \"Conversation has no tasks to fork at this block\");\nlet forked = model.fork_conversation_at_block(conv_id, exchange_id)?;","handlingStrategy":"validation","validationCode":"// Before forking at a block, confirm the conversation has tasks that cross the fork point.\nlet conv = BlocklistAIHistoryModel::as_ref(ctx).conversation(&conversation_id);\nanyhow::ensure!(\n    conv.as_ref().map(|c| !c.tasks().is_empty()).unwrap_or(false),\n    \"Conversation has no tasks to fork at this block\"\n);","typeGuard":"fn can_fork_at_block(conv: &AIConversation, fork_point_exchange: &AIExchange) -> bool {\n    !conv.tasks().is_empty()\n        && conv\n            .tasks()\n            .iter()\n            .any(|t| messages_intersect(t, &fork_point_exchange.added_message_ids))\n}","tryCatchPattern":"match model.fork_conversation_at_block(conv_id, exchange_id) {\n    Ok(forked) => forked,\n    Err(e) if e.to_string().contains(\"Truncated tasks for forked conversation\") => {\n        // benign precondition failure: tell the user there is nothing to fork here\n        show_info_toast(\"Nothing to fork at this block\");\n        return Ok(None);\n    }\n    Err(e) => return Err(e),\n}","preventionTips":["Disable the fork-at-block affordance for conversations with no tasks","Wait for cloud/DB hydration of tasks before enabling fork","Log truncated-task counts per fork attempt to catch truncation-logic regressions early"],"tags":["conversation","fork","state","validation","agent"],"backgroundTag":null,"analyzedSha":"e72fd7aacbbb2236d9b3be2aad7e7178fe94b4bc","analyzedAt":"2026-08-16T08:27:25.381Z","schemaVersion":2},"datasetVersion":"2026-08-16T13:17:31.715Z"}