bug: Incompatibility between DGS 10.0.1 and Spring-GraphQL’s SchemaMappingInspector in Mvc-Tests

[colomdan]

In DGS 10.0.1, we are now running tests with @EnableDgsMockMvcTest.
In these tests, DGS validates our schema using the SchemaMappingInspector from spring-graphql.
This inspector does not allow the same patterns for Java Beans as DGS does. Boolean flags cannot be resolved the following way.

allowed: Boolean!

public Boolean isAllowed() {
    return this.isAllowed;
  }

When I just start the Application everything works without any Issues. It seems the SchemaMappingInspector is only used in Mvc-Tests?

Expected behavior

A schema that works without issues in DGS should also be correctly validated by spring-graphql within tests. Or there should be an option to disable the SchemaMappingInspector in Tests.

Actual behavior

I get the following Exception when I start the test.

Caused by: java.lang.IllegalArgumentException: Method must not be null
	at org.springframework.util.Assert.notNull(Assert.java:172)
	at org.springframework.core.MethodParameter.<init>(MethodParameter.java:128)
	at org.springframework.core.MethodParameter.<init>(MethodParameter.java:114)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkFieldsContainer(SchemaMappingInspector.java:184)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkField(SchemaMappingInspector.java:254)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkFieldsContainer(SchemaMappingInspector.java:185)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkField(SchemaMappingInspector.java:254)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkFieldsContainer(SchemaMappingInspector.java:173)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkField(SchemaMappingInspector.java:254)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkFieldsContainer(SchemaMappingInspector.java:185)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkField(SchemaMappingInspector.java:254)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkFieldsContainer(SchemaMappingInspector.java:173)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkField(SchemaMappingInspector.java:254)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkFieldsContainer(SchemaMappingInspector.java:173)
	at org.springframework.graphql.execution.SchemaMappingInspector.checkSchemaFields(SchemaMappingInspector.java:139)
	at org.springframework.graphql.execution.SchemaMappingInspector.getOrCreateReport(SchemaMappingInspector.java:130)
	at org.springframework.graphql.execution.SchemaMappingInspector$DefaultInitializer.inspect(SchemaMappingInspector.java:447)
	at org.springframework.graphql.execution.SchemaMappingInspector.inspect(SchemaMappingInspector.java:317)
	at com.netflix.graphql.dgs.springgraphql.DgsGraphQLSourceBuilder.setupSchemaReporter$lambda$2(DgsGraphQLSourceBuilder.kt:152)

[paulbakker]

@colomdan I've been trying to reproduce this issue, but haven't been able to.
Could you give some instructions how to trigger this issue?

[colomdan]

Hi @paulbakker

Thank you for your reply.

I created an example project from scratch:
example-project

With the latest Spring version, the SchemaMappingInspector no longer throws exceptions. However, it still incorrectly classifies the ‘allowed’ field as an unmapped field, even though I can query it using GraphiQL.

2025-01-20T11:53:33.134+01:00  INFO 19404 --- [demo] [           main] .d.s.a.DgsSpringGraphQLAutoConfiguration : ***Schema Report***
Unmapped fields: [UserConfig.allowed, Query._service]
Unmapped registrations: {}
Unmapped arguments: []
Skipped types: []

Since no exception is thrown anymore, it is not a big problem for us, but it is probably still not ideal that Spring classifies ‘allowed’ as an unmapped field, even I can query it with DGS.