oven-sh/bun · error · BuildError

Failed to load config file: ${path}

Error message

Failed to load config file: ${path}

What it means

loadConfigFile() in scripts/build.ts reads and JSON.parses the file passed via --config-file (used by ninja's generator-rule replay of the configure step; legacy flat configs are wrapped as overrides). This BuildError wraps any read or parse failure — the file is missing, unreadable, or not valid JSON.

Source

Thrown at scripts/build.ts:369

  const merged = [...bypass].join(",");
  process.env.NO_PROXY = merged;
  process.env.no_proxy = merged;
}

/**
 * Load a ConfigureInput from JSON (for ninja's generator rule replay).
 *
 * Current format: `{ profile?: string, overrides?: PartialConfig }`.
 * Legacy format (pre profile-name persistence): a flat PartialConfig — if we
 * see neither `profile` nor `overrides` keys, wrap the whole object as
 * overrides so old build dirs still regen.
 */
function loadConfigFile(path: string): ConfigureInput {
  let raw: Record<string, unknown>;
  try {
    raw = JSON.parse(readFileSync(path, "utf8")) as Record<string, unknown>;
  } catch (cause) {
    throw new BuildError(`Failed to load config file: ${path}`, { cause });
  }
  if ("profile" in raw || "overrides" in raw) {
    return raw as ConfigureInput;
  }
  // Legacy flat PartialConfig.
  return { overrides: raw as PartialConfig };
}

// ───────────────────────────────────────────────────────────────────────────
// CLI arg parsing
// ───────────────────────────────────────────────────────────────────────────

interface CliArgs {
  profile: string;
  /** PartialConfig overrides from --<field>=<value> flags. */
  overrides: PartialConfig;
  /** Explicit ninja targets from --target=X. Empty = use defaults. */
  ninjaTargets: string[];

View on GitHub (pinned to 8c5296ac45)

Solutions

1. Validate the JSON: jq . <path> to get the exact syntax error
2. Fix the reported syntax error
3. If unsure, delete the config and reconfigure normally — bun bd regenerates it
4. Confirm the path passed via --config-file exists

Example fix

# before — broken JSON (trailing comma)
{ "profile": "debug", "overrides": { "asan": false, } }

# after
{ "profile": "debug", "overrides": { "asan": false } }

import { readFileSync } from "node:fs";
const raw = readFileSync(path, "utf8");
JSON.parse(raw); // surfaces the exact offset before build.ts wraps it
// legacy flat configs are fine — loadConfigFile wraps them as { overrides: raw }

try { loadConfigFile(path); }
catch (e) {
  if (/Failed to load config file/.test(e.message)) {
    console.error(`${path} is not valid JSON — run: jq . ${path}`);
  }
  throw e;
}

When it happens

Trigger: Hand-editing the generated config JSON and leaving a syntax error; pointing --config-file at a stale path after the build dir moved; a truncated file from an interrupted write; encoding/BOM issues.

Common situations: Manually tweaking profile/overrides in the generated JSON and breaking commas; renaming or copying build directories; editors or git operations touching generated files.

Related errors

• Failed to exec ${exe}
• Unknown config field: --${rawKey}
• ${bunProfile} not found — build it first (bun run build:rele
• file did not exist after write: ${outputPath}
• not implemented right

AI-assisted analysis of oven-sh/bun@8c5296ac45 (2026-08-16). Data as JSON: /api/errors/524d42a31b0e3bf6. Report an issue: GitHub.