Multiple passes needed to get final formatting

[goderbauer]

Running dart format on the following code...

import 'dart:io';

bool foo() {
  if (
  // Explicitly stated to not be a bot.
  Platform.environment['BOT'] == 'false'
  ) {
    return false;
  }
  return true;
}

... produces this output:

import 'dart:io';

bool foo() {
  if (// Explicitly stated to not be a bot.
  Platform.environment['BOT'] == 'false') {
    return false;
  }
  return true;
}

Running dort format over that output again reformats it to the following (notice the added space before the //):

import 'dart:io';

bool foo() {
  if ( // Explicitly stated to not be a bot.
  Platform.environment['BOT'] == 'false') {
    return false;
  }
  return true;
}

Expectation: dart format produces the final output after one run. Subsequent runs do not change the output further.

[munificent]

Yeah, the formatter is intended to be idempotent. But, unfortunately, I've never been able to figure out a way to systematically ensure that it is in all cases. We do at least test now that all of the test cases are idempotent.

Most of the places where it fails to be have to do with comments in uncommon locations like here.