{"record":{"id":"e216e68029103117","repo":"earendil-works/pi","slug":"cannot-fork-source-session-has-no-header-resol","errorCode":null,"errorMessage":"Cannot fork: source session has no header: ${resolvedSourcePath}","messagePattern":"Cannot fork: source session has no header: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"packages/coding-agent/src/core/session-manager.ts","lineNumber":1595,"sourceCode":"\t * @param targetCwd Target working directory (where the new session will be stored)\n\t * @param sessionDir Optional session directory. If omitted, uses default for targetCwd.\n\t */\n\tstatic forkFrom(\n\t\tsourcePath: string,\n\t\ttargetCwd: string,\n\t\tsessionDir?: string,\n\t\toptions?: NewSessionOptions,\n\t): SessionManager {\n\t\tconst resolvedSourcePath = resolvePath(sourcePath);\n\t\tconst resolvedTargetCwd = resolvePath(targetCwd);\n\t\tconst sourceEntries = loadEntriesFromFile(resolvedSourcePath);\n\t\tif (sourceEntries.length === 0) {\n\t\t\tthrow new Error(`Cannot fork: source session file is empty or invalid: ${resolvedSourcePath}`);\n\t\t}\n\n\t\tconst sourceHeader = sourceEntries.find((e) => e.type === \"session\") as SessionHeader | undefined;\n\t\tif (!sourceHeader) {\n\t\t\tthrow new Error(`Cannot fork: source session has no header: ${resolvedSourcePath}`);\n\t\t}\n\n\t\tconst dir = sessionDir ? normalizePath(sessionDir) : getDefaultSessionDir(resolvedTargetCwd);\n\t\tif (!existsSync(dir)) {\n\t\t\tmkdirSync(dir, { recursive: true });\n\t\t}\n\n\t\t// Create new session file with new ID but forked content\n\t\tif (options?.id !== undefined) {\n\t\t\tassertValidSessionId(options.id);\n\t\t}\n\t\tconst newSessionId = options?.id ?? createSessionId();\n\t\tconst timestamp = new Date().toISOString();\n\t\tconst fileTimestamp = timestamp.replace(/[:.]/g, \"-\");\n\t\tconst newSessionFile = join(dir, `${fileTimestamp}_${newSessionId}.jsonl`);\n\n\t\t// Write new header pointing to source as parent, with updated cwd\n\t\tconst newHeader: SessionHeader = {","sourceCodeStart":1577,"sourceCodeEnd":1613,"githubUrl":"https://github.com/earendil-works/pi/blob/4af9d21d3b4d664e4a29fcabfec85171077248e3/packages/coding-agent/src/core/session-manager.ts#L1577-L1613","documentation":"Error \"Cannot fork: source session has no header: ${resolvedSourcePath}\" thrown in earendil-works/pi.","triggerScenarios":"Thrown at packages/coding-agent/src/core/session-manager.ts:1595 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"4af9d21d3b4d664e4a29fcabfec85171077248e3","analyzedAt":"2026-08-24T13:07:14.692Z","schemaVersion":2},"datasetVersion":"2026-08-24T17:17:21.512Z"}