thedotmack/claude-mem · error · Error

Corrupt JSON file, refusing to overwrite

Error message

Corrupt JSON file, refusing to overwrite: ${filePath}: ${error instanceof Error ? error.message : String(error)}

What it means

readJsonSafe reads a JSON file and parses it (with BOM tolerance for Windows tooling); if reading or parsing fails, it throws with the file path and underlying message, explicitly refusing to let callers overwrite a file it could not understand. The intent is data protection: an unparseable config file may still hold user edits, so blindly overwriting it would destroy data.

Solutions

1. Open the file, fix the JSON syntax error (or the empty/truncated content), and save
2. Back up the corrupt file, then restore it from a known-good version and rerun
3. If truly unrecoverable, manually move/delete the file so a fresh valid one can be written — after confirming nothing valuable is lost
4. Re-save the file as UTF-8 without BOM if Windows tooling rewrote it

Example fix

// before
const config = readJsonSafe<Config>(path); // throws on corrupt file
// after
let config: Config;
try {
  config = readJsonSafe<Config>(path);
} catch {
  backupCorruptFile(path);
  config = defaultConfig;
}

import { existsSync, readFileSync } from 'fs';
if (existsSync(filePath)) { try { JSON.parse(readFileSync(filePath, 'utf-8').replace(/^\uFEFF/, '')); } catch (e) { console.error('corrupt JSON:', filePath, e.message); } }

try { const cfg = readJsonSafe<Config>(path); }
catch (e) { if (e.message.startsWith('Corrupt JSON file')) { backupAndReset(path); const cfg = readJsonSafe<Config>(path); } else throw e; }

When it happens

Trigger: Calling any consumer (knownMarketplaces, installedPlugins, settings, readMcpConfigTolerantly, etc.) when the target file contains invalid JSON (truncated write, manual edit typo, BOM handled elsewhere, empty file).

Common situations: A crashed process left a half-written settings.json; user hand-edited JSON and introduced a syntax error; PowerShell 5.1 or an editor rewrote the file with a UTF-8 BOM (#3013); file exists but is empty.

Understand the failure class

Background: JSON parse error: "Unexpected token" / "not valid JSON" / "failed to parse" — what JSON parsers are really complaining about — this error's family across 45 libraries.

Related errors

• CLAUDE_MEM_TELEGRAM_WRAPUP_ROUTES must be a JSON object
• ActiveServerQueueManager requires…
• Anthropic API error
• canonical content
• canonical content

AI-assisted analysis of thedotmack/claude-mem@d8bc9755e7 (2026-09-17). Data as JSON: /api/errors/6620b2666e93de6d. Report an issue: GitHub.

Appendix: source

Thrown at src/utils/json-utils.ts:13

import { existsSync, readFileSync } from 'fs';
import { parseJsonWithBom } from '../shared/atomic-json.js';

export function readJsonSafe<T>(filePath: string, defaultValue: T): T {
  if (!existsSync(filePath)) return defaultValue;
  try {
    // Windows tooling (PowerShell 5.1, some editors) may rewrite JSON with a
    // UTF-8 BOM. Node/Bun decode that to U+FEFF at offset 0, which JSON.parse
    // rejects. Strip on read so install/uninstall and other callers survive.
    // See #3013.
    return parseJsonWithBom<T>(readFileSync(filePath, 'utf-8'));
  } catch (error: unknown) {
    throw new Error(`Corrupt JSON file, refusing to overwrite: ${filePath}: ${error instanceof Error ? error.message : String(error)}`);
  }
}

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