Missing @Nullable on type parameter of GraphQlTester.Request#variables(Map<String, Object>)

[darrelldraney]

Describe the bug

The Kotlin-visible signature of GraphQlTester.Request#variables(Map<String, Object> values) in the spring-graphql-test module declares that map values cannot be null, but the JavaDoc explicitly states that null values are supported. This is an inconsistency in the declared contract.

Evidence

The method is declared in GraphQlTester.java:

T variables(Map<String, Object> values);

Its Javadoc states:

@param values the variables to add, possibly with null values since GraphQL supports null for a value vs not providing it at all.

The package is annotated @NullMarked:

@NullMarked
package org.springframework.graphql.test.tester;

Per the JSpecify user guide, inside @NullMarked the type usage Map<String, Object> means non-null keys and non-null values. To allow nullable values the type parameter must be explicitly marked: Map<String, @Nullable Object>.

Comparison with sibling method

The singular setter Request#variable(String name, @Nullable Object value) at line 78 already uses @Nullable on the value parameter, acknowledging that null is a valid variable value. The map form should be consistent with its sibling and its own Javadoc.

Impact

Kotlin consumers cannot pass a map containing null values through variables(...) without @Suppress("UNCHECKED_CAST") as Map<String, Any>, which misrepresents the runtime type and suppresses legitimate null-safety checks. Alternatives such as .filterValues { it != null } silently convert a null GraphQL variable into an absent one — a real semantic change, since GraphQL distinguishes "foo": null from foo being undefined.

Suggested fix

Change the parameter type to:

T variables(Map<String, @Nullable Object> values);

This aligns the declaration with the documented behavior and with the sibling variable(String, @Nullable Object) method, and lets Kotlin consumers pass Map<String, Any?> directly without casts.

Version

Observed on main. The package-level @NullMarked was introduced as part of the JSpecify migration (#1132), so the inconsistency applies to all releases since that migration landed.

[darrelldraney]

Running into a second instance of what looks like the same root cause: GraphQlTester.Path#entityList(Class<D>).

Because spring-graphql-test/.../tester/package-info.java is @NullMarked, the unannotated <D> in:

<D> EntityList<D> entityList(Class<D> elementType);

is implicitly D extends @NonNull Object. But GraphQL list types legitimately permit null elements ([String] = nullable list with nullable elements), so on the client side EntityList<String?> is a valid thing to want.

On Spring Boot 3.5 (spring-graphql 1.4.x) Kotlin was happy with .entityList<String?>(String::class.java). After upgrading to Spring Boot 4.0 (spring-graphql 2.0.x) that no longer compiles — the String? type argument violates the implicit non-null bound from @NullMarked.

The only workaround is to drop the ? and then .filterNotNull() the result, which makes the declared type lie about the runtime contents.

Seems like the same fix shape applies: <D extends @Nullable Object> on entityList (and likely anywhere else @NullMarked is over-constraining generic type parameters in this package).