What option controls how much space is added after a new line?

Question

When I set tw vim will auto wrap lines at tw. When breaking that line vim usually places some spaces to keep the indentation of the previous line. Example

foo
  bar<suppose that a wrap happens here>
  tar
## <- this amount of space is added to keep the line idented

What are the options that control this behavior?

-- edit

To be more precise I was editing markdown and it indents lists this way

- foo bar tar <wrap happens!>
    tick tack

While I expect

- foo bar tar <wrap happens!>
  tick tack

I just don't want to tie the response to markdown so that I can apply it to other formats.

Answer 1

There are too many such options to be able to answer this quesion in a general manner. However, they are mostly programming-languages oriented or exotic ones.

In case of a "text document", such as markdown, you likely have to deal with only autoindent (an alternative is smartindent, as si is sometimes set default in some vimrc's, but si is a sort of "universal programming language" indenter, and you should better keep it off for markdown and such). Also note that autoindent is off by default, so you probably have set ai in your vimrc.

There are also several options which influence number / structure of tabs / spaces in an (auto-)indent, but, I guess, it's not the point of your interest right now.

Also speaking of markdown, it's worth to note that there's formatlistpat option (set by ftplugin) to detect "lists". So "the list items" in markdown will get indented even if set noautoindent.

And the last but not least, autoindent will come in play if you have textwidth set. Not wrap and wrapmargin. The point is that textwidth results in adding "real" newlines in your file (and hence autoindent will do its job). While wrapmargin results in "on-screen" wrapping.