yamlfmt is unstable with folded block scalars starting with the [ character

[svix-jbrown]

This is incredibly bizarre. If you have a folded block scalar (denoted with >) and the first character is a [, yamlfmt becomes unstable and adds an additional newline each time the tool is run

Given the initial input of

key: >
  [
    This is not YAML
  ]

Running yamlfmt on this once yields

key: >
  [

    This is not YAML
  ]

Running it again yields

key: >
  [


    This is not YAML
  ]

and so on.

This doesn't happen if it's an unfolded scalar (i.e., if the first line of my example is key: |) and it doesn't happen for any other first lines in the string (at least, not any I tried).

I can't imagine why the parser would care at all what the contents of a string literal are, but it sure seems to.

[braydonk]

I believe this is a duplicate of #169; I'll close this issue in favour of continuing to track it there. You can find some more context in that issue.