Add option to disable limits added by PR #515

[bartle-stripe]

A limit around aliases was added in #515 that's breaking parsing of YAML files. While I can appreciate wanting to address CVE-2019-11253, it seems like there ought to be an option to disable limits for trusted YAML files.

[niemeyer]

Have you had trouble with the limits? Do you have a real-world sample document you can share?

Thanks for the report.

[bartle-stripe]

It's from internal YAML configuration so I can't directly share it. The general pattern looks like:

common:
   foo: &foo
      <lots of lines>
   bar: &bar
      <lots of lines>
   ...
A:
  << *foo
  << *bar
  something: else
  another: thing

B:
  << *foo
  << *bar
  something: else
  another: thing

We're currently unable to upgrade past that PR, so yes, it's causing trouble.

[niemeyer]

Okay, thanks, I'll look into it. We have a PR that I'm late on reviewing that is the first step towards supporting options in a better fashion. We can add that option afterwards.