oven-sh/bun · error · Error

Memory lifetime is ambiguous when returning UTF8String

Error message

Memory lifetime is ambiguous when returning UTF8String

What it means

Error "Memory lifetime is ambiguous when returning UTF8String" thrown in oven-sh/bun.

Source

Thrown at src/codegen/bindgen.ts:391

      cpp.line("}");
      cpp.line("return JSC::JSValue::encode(JSC::jsUndefined());");
      break;
    case "basic-out-param":
      addCommaAfterArgument();
      cpp.add("&out");
      cpp.line();
      cpp.dedent();
      cpp.line(")) {");
      cpp.line(`    return {};`);
      cpp.line("}");
      const simpleType = getSimpleIdlType(variant.ret);
      if (simpleType) {
        cpp.line(`return JSC::JSValue::encode(WebCore::toJS<${simpleType}>(*global, out));`);
        break;
      }
      switch (variant.ret.kind) {
        case "UTF8String":
          throw new Error("Memory lifetime is ambiguous when returning UTF8String");
        case "DOMString":
        case "USVString":
        case "ByteString":
          cpp.line(
            `return JSC::JSValue::encode(WebCore::toJS<WebCore::IDL${variant.ret.kind}>(*global, out.transferToWTFString()));`,
          );
          break;
      }
      break;
    default:
      throw new Error(`TODO: emitCppCallToVariant for ${inspect(returnStrategy)}`);
  }
}

/** If a simple IDL type mapping exists, it also currently means there is a direct C ABI mapping */
function getSimpleIdlType(type: TypeImpl): string | undefined {
  const map: { [K in TypeKind]?: string } = {
    boolean: "WebCore::IDLBoolean",

View on GitHub (pinned to 8c5296ac45)

When it happens

Trigger: Thrown at src/codegen/bindgen.ts:391 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of oven-sh/bun@8c5296ac45 (2026-08-16). Data as JSON: /api/errors/85dfed09c1d63ed0. Report an issue: GitHub.