validator/rules.sameArguments does not work as intended

[jufemaiz]

The current implementation of sameArguments is invalid due to early exit in the loops.

https://github.com/graphql/graphql-js/blob/main/src/validation/rules/OverlappingFieldsCanBeMergedRule.ts#L626-L642

function sameArguments(
  arguments1: ReadonlyArray<ArgumentNode>,
  arguments2: ReadonlyArray<ArgumentNode>,
): boolean {
  if (arguments1.length !== arguments2.length) {
    return false;
  }
  return arguments1.every((argument1) => {
    const argument2 = arguments2.find(
      (argument) => argument.name.value === argument1.name.value,
    );
    if (!argument2) {
      return false;
    }
    return sameValue(argument1.value, argument2.value);
  });
}

As can be seen here, the first step in the loop on args1 is to discover the matching argument in args2 by name. If it can't be found, return false, otherwise true if matching or false if not – but javascript has the extra nice every option to ensure that each iteration is true.

The current golang implementation ignores the every, and as such will throw invalid if there is more than one argument in the slice.

	for _, arg1 := range args1 {
		for _, arg2 := range args2 {
			if arg1.Name != arg2.Name {
				return false
			}
			if !sameValue(arg1.Value, arg2.Value) {
				return false
			}
		}
	}
	return true

#170 also adds test cases to cover this capability.