Circular input property leads to stackoverflow

[KammererTob]

After updating graphql-java-tools to 6.1.0 i have encountered a stackoverflow exception on startup. I think that the problem was introduced in this commit: 10ee43f and happens because of the interaction between determineInputType and createInputObject.
Example schema:

input A {
    id: ID!
    b: B
}

input B {
   id: ID!
   a: A
}

According to the spec this should be allowed (graphql/graphql-spec#445, graphql/graphql-spec#189), which leads me to believe that this is a bug.

[vojtapol]

Confirmed bug. Contributions welcome.

[enriquedacostacambio]

fyi, simple (non-mutual) recursion also triggers the bug:

input CriterionInput {
    and: [CriterionInput!]
    or: [CriterionInput!]
    not: CriterionInput
    status: StatusCriterionInput
}

input StatusCriterionInput {
    eq: String
}

[PhilippS93]

Can confirm. This is especially important for filtering purposes like recursive OR and AND patterns.