v3: idempotency in file formatter

[mtojek]

Hi,

I planned to adopt go-yaml/yaml.v3 in a small YAML formatter (simple "unmarshal and marshal"). It looks to work great with yaml.Node, it preserves comments, field ordering, but fails with the following pattern:

- first:
    second: >-
      aaaa
        bbbb
          cccc

The outcome of formatting is:

- first:
    second: >-
      aaaa

        bbbb
          cccc

What is more, formatting such file twice gives even worse output:

- first:
    second: >-
      aaaa


        bbbb
          cccc

(double new line)

I wonder if I can use the library to implement a formatter.

BTW It would be great to increase the control over rendering, e.g. total line length, fields stored in memory as is (use case: I don't want to format this field).

[felixfontein]

I can reproduce this, but I'm not sure how to fix this. The code which causes this is identical to the corresponding code in libyaml (and hasn't changed for many years).

[calebAtIspot]

idempotency would be great as it would help fix mikefarah/yq#465