JSON Schema path pattern

[kstasik]

Can you explain why there is an escape character before / in json schema of openapi specification?

https://github.com/OAI/OpenAPI-Specification/blob/master/schemas/v3.0/schema.json#L793

I tried to find a reason why it's there in https://json-schema.org/understanding-json-schema/reference/regular_expressions.html and https://www.ecma-international.org/publications/standards/Ecma-262.htm but i'm still not sure about it. I didn't find any explanation in specs.

IMO this regexp is invalid, it only works in most of libraries because javascript automatically fixes invalid usages of escape character.

[handrews]

@kstasik that's because "^\\/" is a JSON string, not a raw regexp. The parsed string would be ^\/ which is a valid regexp.

[karenetheridge]

Isn't ^/ also a valid regexp?

[handrews]

@karenetheridge huh... yeah that would make more sense. If \ is a no-op before non-special characters, than ^\/ and ^/ would be the same. If \ is a literal \ before non-special characters, then their different. I can't be bothered to look it up right now, and it might vary among implementations given how variable regexp implementations are anyway.

[kstasik]

Honestly i wouldn't even notice it, in languages like nodejs, php^\/ is valid regexp but in rust implementation of regexp it's not. That's why i suggested to change it to ^/ which works well in all mentioned languages.

Out of curiosity i tried to find out which implementation of regexp is valid according to ecma standard but i just failed in reasonable amount of time.