Collection key type in YAML breaks map range order

[dmgawel]

When defining a collection in Hugo data file using YAML format it is then parsed as map[interface {}]interface {}. This fundamentally differs from TOML and JSON which parses collections to map[string]interface {}.

Example (YAML):

test:
  a: 1
  b: 2

is parsed to:

map[interface {}]interface {}{"a":1, "b":2}

Example (TOML):

[test]
a = 1
b = 2

is parsed to:

map[string]interface {}{"a":1, "b":2}

Example (JSON):

{
  "test": {
    "a": 1,
    "b": 2
  }
}

is parsed to:

map[string]interface {}{"a":1, "b":2}

As YAML is a superset of JSON one can suppose the same key type in both formats.

The following have a great effect on ranging over maps. From the range docs:

If the value is a map and the keys are of basic type with a defined order ("comparable"), the elements will be visited in sorted key order.

Apparently string is comparable, unlike interface{}.

[dmgawel]

I came across another issue with this behaviour. map[interface {}]interface {} is not 'jsonifiable'. Given data in test.yaml executing: {{ .Site.Data.test | jsonify }} outputs:

ERROR 2017/11/15 14:43:43 Error while rendering "home": template: index.html:8:23: executing "index.html" at <jsonify>: error calling jsonify: json: unsupported type: map[interface {}]interface {}

[bep]

I assume this is a go-yaml upstream issue -- and I think I have seen it before?

[moorereason]

Duplicate of #2441

[github-actions]

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