[sapling-ginger]

> in any configuration language that supports comments

Notably, not JSON. In fact JSON doesn't support comment specifically to prevent this. And YAML was created specifically to add comments to JSON, in violation of this precaution. So YAML can eat the lunch that it serve itself.

[woodruffw]

I have seen plenty of JSON applications abuse the "$" key namespace for comments. JSON Schema, for example, uses `$comment`[1]. So no, I don't think this is a shingle that can be uniquely hung around YAML's neck.

The Norway problem, anchors & references, infinite ways to begin a multi-line string, on the other hand, are all legitimate grievances that are somewhat unique to YAML.

Edit: And note: what makes this hack bizarre is that they chose to do it in comments, despite YAML having ample syntax for an inline dictionary or whatever else. YAML offers all kinds of exquisitely complicated ropes to hang yourself with, and they chose plain old boring comments!

[1]: https://json-schema.org/understanding-json-schema/reference/...

[devsda]

> In fact JSON doesn't support comment specifically to prevent this.

They were mainly concerned about interoperability but partially yes.

Source: https://web.archive.org/web/20190112173904/https://plus.goog...

[lifthrasiir]

You can exploit any ambiguity besides from comments. JSON in particular doesn't fully forbid duplicate keys in objects (though many implementations do reject them), and I think they were already abused as comments in the past. And you can always use special keys like `$when` (a la MongoDB) to add turing completeness, so even that point is moot.