Updating existing empty map results in single-line yaml syntax

[marcostvz]

Describe the bug
As described in https://mikefarah.gitbook.io/yq/operators/assign-update#update-empty-object-and-array, updating a file with an existing empty map results in a one-liner yaml. In our use case, this makes helm template to break.

Version of yq: 4.24.2
Operating system: tested on mac and linux
Installed via: homebrew for mac, binary release for linux

Input Yaml
fields.yaml:

global: {}

Command

yq eval '.global.test = "val"' fields.yaml

Actual behavior

global: {test: val}

Expected behavior

global:
  test: val

Additional context
If we work with an empty file, or a non-existing key, the format is correct:

$ yq eval '.global.test = "val"' empty-fields.yaml
global:
  test: val

$ yq eval '.other.test = "val"' fields.yaml
global: {}
other:
  test: val

Also, as a workaround, we can parse it to json and back to yaml and the format is correct:

$ yq eval '.global.test = "val"' fields.yaml -o json | yq -P '.' -
global:
  test: val

[mikefarah]

Yeah this is a side effect of yq trying to maintain the styling used in the document. I'm surprised helm doesn't like it as it's perfectly valid yaml.

I'll look into making it a bit smarter for scenarios like this, till then you can:

yq -P '.global.test = "val"' fields.yaml

[mikefarah]

Fixed in 4.24.5

[krokofant]

I want to have the empty map converted to a single line definition when updated. Seems there is no way to achieve this now.

I have branches with commits changing something like:

foo1:
  bar: true

and

foo2:
  bar: true

Now merging these automatically would result in (depending on which way)

foo1:
foo2:
  bar: true

If I could maintain the yaml in a single line, then I could work around this issue. The merge would be:

foo1: { bar: true }
foo2: { bar: true }

I expected combining these commands would preserve the inline format:

yq e -i ".foo1 = {}" myvalues.yaml
yq e -i ".foo1.bar = true" myvalues.yaml