Can you please try #44034?

Work fine now for quoted string, but still broken for !!str

parameters:
    # Correct output
    #
    # bin/console debug:container --parameters
    # output -> ["&string"]
    collection_output_correct:
        - !!str &string

    # Wrong output
    #
    # bin/console debug:container --parameters
    # output -> [""]
    collection_output_wrong: [!!str &string]

You are right. There was an issue with how we handled quoted scalars tagged with !!str. #44131 will fix that and your YAML should look like this then to work as expected:

parameters:
    # Correct output
    #
    # bin/console debug:container --parameters
    # output -> ["&string"]
    collection_output_correct:
        - !!str '&string'

    # Wrong output
    #
    # bin/console debug:container --parameters
    # output -> [""]
    collection_output_wrong: [!!str '&string']

But what about !!str &string - !!str without quoted scalars with the first character &?

Still two equivalent syntax of yaml-Collections produce different output:

parameters:
    collection_1:
        - !!str &string

    collection_2: [!!str &string]
    
    # parser output collection_1: ["&string"]
    # parser output collection_2: [""]

You have to quote them. If I do not miss anything, this simply is how it is supposed to be done according to the spec.

I have nothing against this or that specification. I disagree only with the fact that for the same expression, depending on the form of writing the collection (in one line or column), the parser gives different results.
In my opinion, the result should be the same.
No one expects the parser's result to change when you change the collection's spelling from column to line.

I was under the expression that the first one would now also end with an empty string. If that’s not the case that should be fixed as well.

Hey, thanks for your report!
There has not been a lot of activity here for a while. Is this bug still relevant? Have you managed to find a workaround?