Roundtrip to/from a property file breaks

[Kopfbremse]

Version of yq: 4.29.2
Operating system: linux
Installed via: binary release

Describe the bug
If a YAML contains keys that are numbers, the roundtrip YAML --> PROP and back PROP --> YAML fails.
This is because numbers are interpreted as array indexes and not as key names. See my feature proposal below.

Input Yaml

error:
  count:
    404: 1
    500: 3
  msg:
    404: unavailable
    500: internal server error

Command 1
Step 1: Convert YAML to PROPS
yq --output-format props '.' "$FILE_YAML"

error.count.404 = 1
error.count.500 = 3
error.msg.404 = unavailable
error.msg.500 = internal server error

Command 2
Step 2: Convert PROPS back to YAML
yq --input-format props $FILE_PROPS

error:
  count:
    - null
    - (...)
    - "1"
    - null
    - (...)
    - "3"
  msg:
    - null
    - (...)
    - unavailable
    - null
    - (...)
    - internal server error

Expected behavior
Command 2 should generate the input of step 1 to achieve a working roundtrip

Feature proposal
It would be nice if there were new options to control the conversion from PROP to YAML more detailed,
e.g. --props-number-handling = [arrayIndex, keyName].
I love the yq support of property files. However, since it is perfectly valid to use numbers in property files, I consider it an incomplete feature.

[mikefarah]

Yeah I see. I'll have to think about this - issue with a flag is that it wouldn't work if you had a mix of arrays and numeric keys.

[mikefarah]

As a workaround, would it be ok to cast the numbered keys to strings (e.g. "400") before converting to props, and then parse them as numbers again after reading from props?

[Kopfbremse]

You are right ... a general option for the whole decoding process is not sufficient.
What do you think about:

Leave the default behaviour as it is (treat numbers in key paths as array index).
Add an option to define exceptions to the default behaviour for a list of paths:

--props-numbers-as-keys = 'error.count.*, error.msg.*'

or equivalent in the upper use case:

--props-numbers-as-keys = 'error.*'

Think of all those properties files out there in the wild. Wouldn't it be nice to process them with yq?
A typical roundtrip would then be the other way around PROPS -> YAML -> PROPS to process a property file.
Since the source in this case is not YAML, your idea of encoding numbers in YAML as strings in the prop file does not help here.

[mikefarah]

I'm always thinking of property files out in the wild. I see them in my dreams :)

I think the right way to do it is via expressions. I'll add a array_to_map operator which will do the conversion, then you'll need to do:

yq -p=props '(.error.count, error.msg) |= array_to_map' file.props

Will add in the next release

[Kopfbremse]

That's a good idea!
Thanks for the extension in the next release.
I am very pleased how quickly you respond.

[Kopfbremse]

They have already implemented and tested it in less than a day since I raised this issue?
That's mind-boggling to me!

[mikefarah]

Fixed in 4.30.1 - https://mikefarah.gitbook.io/yq/operators/array-to-map