Ruamel yaml

[A2va]

Hello ! I replaced pyyaml by Ruamel. This is needed by beetbox/beets#4188 and fixes #52

I removed the hack to keep comments but is there another hack elsewhere ?

[sampsyo]

Awesome; thanks for getting this started!

One other thing that #52 mentions is the OrderedDict extension. You can see where we preserve dictionary order here: https://github.com/beetbox/confuse/blob/c328e810f7a31412e0650235f71728e983edd18e/confuse/yaml_util.py#L31

It might be nice to check whether the new library correctly does the same thing in an out-of-the-box way.

Have you been able to test yet whether this switch is effective at preserving comments, even without our hack?

[A2va]

It might be nice to check whether the new library correctly does the same thing in an out-of-the-box way.

I checked and ruamel uses OrderedDict .

Have you been able to test yet whether this switch is effective at preserving comments, even without our hack? I tested it and for now it doesn't work,

It seems that more work is needed. But I have read the documentation and managed to get a working example.

from ruamel.yaml import YAML
from pathlib import Path

input = Path('./input.yaml')
output = Path('./output.yaml')
yml = YAML()
data = yml.load(input)
data["import"]["write"] = False
yml.dump(data, output)

To handle round tripping ruamel has special Dumper and Loader. With an empty type in YAML constructor, ruamel take automatically the round tripping classes. I tried to inherit RoundTripDumper to confuse Dumper and same for Loader but I couldn't get it to work

[A2va]

I found the problem when the yaml file loaded with yaml_util.load_yaml function. ruamel create special entry in class for handling comment but with update function, this information is lost.

https://github.com/beetbox/confuse/blob/c328e810f7a31412e0650235f71728e983edd18e/confuse/sources.py#L79-L86

I also found an example closer to pyyaml api and this the old API of ruamel.

input = Path('./input.yaml')
with input.open() as ifile:
    doc = yaml.load(ifile, Loader=yaml.RoundTripLoader)
    print(yaml.dump(doc, Dumper=yaml.RoundTripDumper))

[A2va]

I also notice that round tripping doest't keep all comments but it appear only with old API of ruamel (example code from my previous message).

The first and second comment are dumped correctly but not the third one. Used the new API solves this but I don't see anything to custom the Dumper with the new API. The new API is like the first example I send,

#First comment
firstkey:
  # Second comment
    test:
      name: test
      # Third comment
      arrive: yes

ruamel.yaml is a YAML parser/emitter that supports roundtrip preservation of comments, seq/map flow style, and map key order

According to the description on pypi, it confirm that ruamel keeps key order.