Directive definition is changed from pruning.

[Samjin]

Issue workflow progress

Progress of the issue based on the Contributor Workflow

• 1. The issue provides a reproduction available on Github, Stackblitz or CodeSandbox

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• 2. A failing test has been provided
• 3. A local solution has been provided
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Describe the bug

The scalar _FieldSet is removed from directive definition.

It's not breaking client because the graphql tool selectively prune unused types from a schema, but it removes parameter from directive definition. In this case, when the schema didn't use a directive, it will remove scalar _FieldSet from directive.
Removing directive's parameter alters its definition, and these fields: _FieldSet! is required for the directive. I think we should either keep the fields: _FieldSet! or remove directive completely so the definition remains correct in schema.

To Reproduce
Codesandbox link

Expected behavior
Do not remove types used in directive definition

Environment:

• OS: MacOS
• @graphql-tools/utils: 9.1.4
• NodeJS: 14

Additional context

[ardatan]

Could you create a PR with a failing test? Thanks!

[Samjin]

hi @ardatan here it is CodeSandbox link

[ardatan]

PRs are welcome as I already said in my previous PR :) to fix it or at least with a failing test if anyone is interested in.