omegaconf: Unexpected behavior for multiline-strings

Describe the bug Hey, I’m trying to have a config, where some values are in an escaped interpolation, but in a multiline-string. I think this is a really specific use case, but I think that this applies to all escaped characters.

To Reproduce

from omegaconf import OmegaConf as oc, Node

correct = {
    "config": {
        "subconfig": "MULTILINE \n    ${tag:ENV}",
    },
    "values": "${config}",
}

wrong = {
    "values": "${config}",
    "config": {
        "subconfig": "MULTILINE \n    ${tag:ENV}",
    },
}


def escape_tag(input: str, _node_: Node):
    """resolver function, that returns an escaped tag with the input"""
    if "\n" in str(_node_):  # multiline-strings
        escape = "\\\\\\"  # \\\
    else:
        escape = "\\"  # \

    return escape + "${" + input + "}"


oc.register_new_resolver("tag", escape_tag)


cfg_correct = oc.create(correct)
cfg_wrong = oc.create(wrong)

oc.resolve(cfg_correct)
oc.resolve(cfg_wrong)

print(cfg_correct["values"])
# >>> {'values': {'subconfig': 'MULTILINE \n    \\${ENV}'}}
print(cfg_wrong["values"])
# >>> {'values': {'subconfig': 'MULTILINE \n    \\\\\\${ENV}'}

### Another bug ?
print(cfg_correct["values"]["subconfig"])
# >>> [...] ${ENV}
print(cfg_wrong["values"]["subconfig"])
# >>> [...] \${ENV}

Explanation Here I have two configs correct and wrong and the only difference between them is the key order in the python file. Then I have a custom resolver that produces me an escaped interpolation. In multiline-strings \ has to be escaped and because of the double escapes (https://github.com/omry/omegaconf/pull/695#discussion_r621335546) we need 3 \. Now the diff is that in the wrong config, each \ is escaped again, and it produces 6 \.

Another bug (?) is, that when I print the actual strings, that the string gets dumped as multiline and not as quoted, but this could be intended.

Expected behavior I expect, that the order in the config doesn’t matter and both configs produce \${ENV}.

If there is any kind of workaround like sorting the keys in the config, I would be happy already.

Additional context

• OmegaConf version: latest / master / 2.4.0.dev0
• Python version: 3.10.12
• Operating system: Linux Ubuntu
• Please provide a minimal repro