Decoding string value of only + (unquoted) fails

[TBeijen]

Behaviour

When decoding yaml documents having values of just + (unquoted), decoding fails with the following error:

cannot parse "+" as tag:yaml.org,2002:int

Expected

The + values to be interpreted as string

Additional info

Encountered this error while using Terraform yamldecode function, which uses go-cty-yaml.

See temporary repo that illustrates the error: https://github.com/TBeijen/terraform-go-cty-yaml-decode-error

Sample document triggering error:

name: +
web_origins:
  - /foobar