Throw From Finally (ARCH3155)

Key typescript.logging.throw-in-finally · Severity error · Category logging

Throwing an exception inside a finally block masks any exception still in flight from the try body. The original error is lost and only the finally error propagates.

Incorrect

function writeReport(file: FileHandle, data: string) {
  try {
    file.write(data);
  } finally {
    file.close(); // if this throws, it masks the try exception
  }
}

Correct

function writeReport(file: FileHandle, data: string) {
  try {
    file.write(data);
  } finally {
    try {
      file.close();
    } catch (closeErr) {
      logger.warn("failed to close file", { closeErr });
    }
  }
}

Fix

Wrap cleanup code in finally with its own try/catch and log rather than propagate.