No Projection is generated for Mutations only ProjectionRoot

[jamesHau]

I'm currently having issues with testing out queries in integration tests using the codgen. I can't figure out why there is no getTemporaryUploadUrlProjection class generated. For every other type there is a <TYPENAME>Projectiongenerated. I can't figure out what is the reason for the Projection class not being generated and would be grateful for some guidance.

These are the following classes which got generated:

• GetTemporaryUploadUrlGraphQLQuery
• GetTemporaryUploadUrlProjectionRoot

However when I try the following code:

final GetTemporaryUploadUrlProjectionRoot<?, ?> projection =
    new GetTemporaryUploadUrlProjectionRoot<>()
        .url();
new GraphQLQueryRequest(
    GetTemporaryUploadUrlGraphQLQuery.newRequest().build(),
    projection
    ).serialize()

I get the following error null cannot be cast to non-null type com.netflix.graphql.dgs.client.codegen.BaseProjectionNode

Which can be traced back into the serialize method of com.netflix.graphql.dgs.client.codegen.GraphQLQueryRequest which does a check and fails on the error message if root is null. Root is null for all ProjectionRoot classes.

Decompiled kotlin to java

      if (this.projection instanceof BaseSubProjectionNode) {
         ProjectionSerializer var10001 = this.projectionSerializer;
         Object var9 = ((BaseSubProjectionNode)this.projection).root();
         if (var9 == null) {
            throw new NullPointerException("null cannot be cast to non-null type com.netflix.graphql.dgs.client.codegen.BaseProjectionNode");
         }

The ProjectionRoot class signature

public class GetTemporaryUploadUrlProjectionRoot<PARENT extends BaseSubProjectionNode<?, ?>, ROOT extends BaseSubProjectionNode<?, ?>> extends BaseSubProjectionNode<PARENT, ROOT> {
  public GetTemporaryUploadUrlProjectionRoot() {
    super(null, null, java.util.Optional.of("TemporaryUploadUrlResponse"));
  }

---

Relevant Schema

type Mutation {
    getTemporaryUploadUrl: TemporaryUploadUrlResponse
}

type TemporaryUploadUrlResponse {
    url: String!
}

My pom.xml (running coretto java 21)

<build>
        <plugins>
            <plugin>
                <groupId>io.github.deweyjose</groupId>
                <artifactId>graphqlcodegen-maven-plugin</artifactId>
                <version>1.61.5</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <schemaPaths>
                        <param>src/main/resources/schema/mutation.graphqls</param>
                        <param>src/main/resources/schema/query.graphqls</param>
                        <param>src/main/resources/schema/scalars.graphqls</param>
                        <param>src/main/resources/schema/types.graphqls</param>
                    </schemaPaths>
                    <packageName>com.randomorg.api.generated</packageName>
                    <generateClientApiV2>true</generateClientApiV2>
                    <skipEntityQueries>false</skipEntityQueries>
                    <addGeneratedAnnotation>true</addGeneratedAnnotation>
                    <typeMapping>
                        <BigDecimal>java.math.BigDecimal</BigDecimal>
                        <PositiveInt>java.lang.Integer</PositiveInt>
                        <NonNegativeInt>graphql.scalars.numeric.NonNegativeIntScalar</NonNegativeInt>
                    </typeMapping>
                </configuration>
            </plugin>

[jamesHau]

I tried to move the code into query but the Projectionclass is still not being generated.

[deweyjose]

Hi @jamesHau

Could you take a look at the companion example repo? It has an example of a client query construction for both queries and parameterized mutations.

For example - here's the code I have to call the createShow mutation.

Can you share what version of the following you're using?

<dependency>
      <groupId>com.netflix.graphql.dgs.codegen</groupId>
      <artifactId>graphql-dgs-codegen-shared-core</artifactId>
    </dependency>