Empty String as As input variable about graphql-core

[eMerzh]

interestingly, i've just noticed that it work as expected if i provide the value as variable and not inline
like this

import asyncio
from graphql import graphql, parse, build_ast_schema


async def resolve_hello(obj, info, query):
    print(query)
    return f'world ==>{query}<=='

schema = build_ast_schema(parse("""
type Query {
    hello(query: String!): String
}
"""))

schema.get_type("Query").fields["hello"].resolve = resolve_hello

async def main():
    query = 'query Space($z: String!) { hello(query: $z) }'
    print('Fetching the result...')
    result = await graphql(schema, query, variable_values={"z": ""} )
    print(result)


loop = asyncio.get_event_loop()
try:
    loop.run_until_complete(main())
finally:
    loop.close()

which let me thing to a bug 🤔

[Cito]

Thanks a lot for reporting. I can confirm this is a bug in the lexer.

[Cito]

The above fix should solve this and will be included in the next release.