printSchema produces incorrect AST for descriptions ending in \ (backslash)

[pcarrier]

import { buildASTSchema, parse, printSchema } from 'graphql';
console.log(printSchema(buildASTSchema(parse(`"Example\\\\" scalar Foo`))));

=>

"""Example\"""
scalar Foo

Which parse does not accept.

[IvanGoncharov]

@pcarrier Thanks for reporting 👍
Definitely something we need to address.

[thenamankumar]

@IvanGoncharov what should be the correct result?

[IvanGoncharov]

@hereisnaman It should be reproducible even with:

const sdl = `
"""Example\\"""
scalar Foo
`;
expect(print(parse(sdl))).to.equal(sdl);

So it's not an issue with printSchema it's an issue with how we are printing block strings in general.

[pcarrier]

Oh yeah sorry I didn't mean to imply this was specific to schemas, absolutely a general printer issue, it's just where we reproduced it by leveraging the wealth of customer data our platform manages and that's the easiest way to make GraphQL-js produce those strings itself I could think of.

[IvanGoncharov]

@pcarrier No worries.
I'm mentoring @hereisnaman as part of "Google Summer of Code" and this issue is an excellent opportunity for him to learn how parser/printer works.
So my comments intended to guide him in the right direction so he could figure how to fix this issue.