Fix: no-multi-spaces false positive with irregular indent whitespace

[not-an-aardvark]

What is the purpose of this pull request? (put an "X" next to item)

[x] Bug fix

Tell us about your environment

• ESLint Version: master
• Node Version: 7.8.0
• npm Version: 4.2.0

What parser (default, Babel-ESLint, etc.) are you using?

default

Please show your full configuration:

rules:
  no-multi-spaces: error

What did you do? Please include the actual source code causing the issue.

foo
<FF>  bar; // <FF> represents a form feed character

What did you expect to happen?

I expected no error to be reported because the whitespace is at the beginning of the line.

What actually happened? Please include the actual, raw output from ESLint.

The code was autofixed to invalid syntax:

foo bar;

What changes did you make? (Give an overview)

The no-multi-spaces rule is not intended to check whitespace at the beginning of a line, because consecutive spaces are often used for indentation. Due to a bug, the rule previously matched against consecutive spaces that appeared after an irreglar whitespace character at the beginning of a line. The rule's autofixer assumes that the detected spaces are always between two tokens on the same line, so it would sometimes produce invalid syntax if the rule matched whitespace at the beginning of a line. This commit updates the rule to avoid matching whitespace at the beginning of a line.

Is there anything you'd like reviewers to focus on?

Nothing in particular

[eslintbot]

LGTM

[mention-bot]

@not-an-aardvark, thanks for your PR! By analyzing the history of the files in this pull request, we identified @btmills, @nzakas and @vegetableman to be potential reviewers.

[not-an-aardvark]

CI is failing due to nodejs/nodejs.org#1191

edit: it's passing now

[platinumazure]

A bit concerned about the Travis failures but LGTM