Multi-line indents do not preserve partial indents

[lewisl9029]

• VSCode Version: 1.7.1
• OS Version: macOS Sierra 10.12.1

I'm using VSCode for Clojure editing right now and have been running into this issue a lot. This seems to be a general problem with VSCode's indentation mechanism though, and not a language specific problem. I've also verified that it's reproducible on the latest master build without any extensions or customizations applied.

Steps to Reproduce:

1. Set indentation to 2 spaces
2. Paste the following into an empty editor:

  {:key1 :value1
   :key2 :value2}

3. Select both lines and press tab

Expected:

Both lines are indented by the standard indentation size of 2 spaces. This is the standard behavior in Atom, as well as most other editors I've worked with:

Actual:

Both lines are indented to the same indentation level, and the partial indent on the second line is discarded:

I tried poking around in the source code a bit but couldn't quite figure out where this functionality lives. If someone could just point me in a general direction, I can try giving it another shot.

[normalser]

Something similar: #9409

[ramya-rao-a]

@alexandrudima Would this be tracked as part of #15598 or separate?

[alexdima]

Today, indenting and unindenting always tries to "snap" the text to tab stops.

I think we could piggy back on the existing setting editor.useTabStops and "snap" the text to tab stops only when the setting is off.

[alexdima]

This works as expected when using "editor.useTabStops": false.