Serialization: field-literal converted to field since 1.39.0

[flamber]

Describe the bug
Regression since 1.39.0, which kinda reopens #15048, but keeping as new issue, since it seems to be different and "only" breaking all field-literal dimensions, which are converted to field.

EDIT: Could it simply be caused by Serialization correctly dumping as field, but the load process reads sum as a file reference, which then results in a null value on the target instance?

To Reproduce
See #15048 for steps.

On 1.39.0 it creates the following dump - only showing a snippet, since #15812 caused a lot of other problems

...
    filter:
    - '>'
    - - field
      - sum
      - base-type: type/Float
    - 100
...

On 1.38.4 it does a correct dump:

...
    filter:
    - '>'
    - - field-literal
      - sum
      - type/Float
    - 100
...

[jeff303]

Commit 8 under #15858 should fix this one.

[camsaul]

Dumping as field is by design. field-literal isn't used anymore. Everything is a field. So it seems like it is an issue with load

[jeff303]

Dumping as field is by design. field-literal isn't used anymore. Everything is a field. So it seems like it is an issue with load

Yes, this is fixed by this commit. The "real problem" in this case was that the string was always being interpreted by load as a fully qualified name, when in fact, it can sometimes just be a string (ex: like in this case).

[flamber]

Fixed by #15858 - will be part of 1.39.3