infinite loop with nested .only()

[adamjmurray]

Run the following test through mocha 3.0.1:

var assert = require('assert');

describe('Array', function() {

  describe.only('.push()', function() {

    it.only('appends a value to the end of the array', function() {
      var array = [1];
      array.push(2);
      assert.deepEqual(array, [1, 2]);
    });
  });
});

Mocha exits with an exception that seems to indicate an infinite loop occurred:

RangeError: Maximum call stack size exceeded
    at filterOnly (/Users/adam/workspace/cirrus/node_modules/mocha/lib/runner.js:857:23)
    at /Users/adam/workspace/cirrus/node_modules/mocha/lib/runner.js:861:9
    at Array.forEach (native)
    at filterOnly (/Users/adam/workspace/cirrus/node_modules/mocha/lib/runner.js:857:23)
    at /Users/adam/workspace/cirrus/node_modules/mocha/lib/runner.js:861:9
    at Array.forEach (native)
    at filterOnly (/Users/adam/workspace/cirrus/node_modules/mocha/lib/runner.js:857:23)
    ...

This is a simplified example. In practice, I sometimes focus on getting a single it.only() test passing, and then go "up a level" and test a group of related tests via a describe.only() block.

Not a blocker. Workaround: don't use nested .only()

[not-an-aardvark]

Can reproduce. The issue is that the suite is attempting to filter its own only suites here, rather than its children's only suites. I'll make a PR.