[AsyncAPI] NullPointerException in MapperContentUtil.java

[gaby-roland]

I keep getting NullPointerException errors originating in MapperContentUtil.
Specifically, line 390.

         if (value.has(REF)) {
            typeObject = MapperUtil.getRef(value, prefix, suffix);
          }
          field.setImportClass(getImportClass(typeObject));
          field.setDataType(typeObject);
          final String[] path = MapperUtil.splitName(value.get(REF).textValue());

It looks like on the last line in the snippet, value.get(REF) is null, which explains why a few line before it there is a if (value.has(REF)), but this check is not taken into consideration on 390 and value.get(REF) is assumed to be non-null.

I saw this error whenever I try have an object nested inside another object, for example in the yaml below, someOtherObject is nested inside of userSignedUpPayload:

asyncapi: "2.0.0"
info:
  title: Demo API
  version: "1.0.0"

channels:
  user/signedup:
    subscribe:
      operationId: emitUserSignUpEvent
      message:
        $ref : '#/components/messages/UserSignedUp'

components:
  messages:
    UserSignedUp:
      name: userSignedUp
      title: User signed up event
      summary: Inform about a new user registration in the system
      contentType: application/json
      payload:
        $ref: '#/components/schemas/userSignedUpPayload'

  schemas:
    userSignedUpPayload:
      type: object
      properties:
        firstName:
          type: string
          description: "foo"
        lastName:
          type: string
          description: "bar"
        email:
          type: string
          format: email
          description: "baz"
        createdAt:
          type: string
          format: date-time
        someOtherObject:
          type: object
          properties:
            property1:
              type: string
            property2:
              type: integer

This causes the following error:

Caused by: java.lang.NullPointerException
    at com.sngular.api.generator.plugin.asyncapi.util.MapperContentUtil.setFieldType (MapperContentUtil.java:390)
    at com.sngular.api.generator.plugin.asyncapi.util.MapperContentUtil.processFieldObjectList (MapperContentUtil.java:245)
    at com.sngular.api.generator.plugin.asyncapi.util.MapperContentUtil.processFieldObject (MapperContentUtil.java:156)
    at com.sngular.api.generator.plugin.asyncapi.util.MapperContentUtil.getFields (MapperContentUtil.java:128)
    at com.sngular.api.generator.plugin.asyncapi.util.MapperContentUtil.buildSchemaObject (MapperContentUtil.java:82)
    at com.sngular.api.generator.plugin.asyncapi.util.MapperContentUtil.mapComponentToSchemaObject (MapperContentUtil.java:66)
    at com.sngular.api.generator.plugin.asyncapi.AsyncApiGenerator.fillTemplateFactory (AsyncApiGenerator.java:538)
    at com.sngular.api.generator.plugin.asyncapi.AsyncApiGenerator.processSubscribeMethod (AsyncApiGenerator.java:524)
    at com.sngular.api.generator.plugin.asyncapi.AsyncApiGenerator.processOperation (AsyncApiGenerator.java:336)
    at com.sngular.api.generator.plugin.asyncapi.AsyncApiGenerator.processFileSpec (AsyncApiGenerator.java:172)

[jemacineiras]

HI @gaby-roland,

Looks like you found a hole in our AsyncApi specification support. I'll check it and provide a solution ASAP.

Cheers

[jemacineiras]

HI @gaby-roland,

I provide a fix in a branch attached to this issue. Do you mind test if it works for you?

Cheers

[gaby-roland]

Hi @jemacineiras

I pulled and built your branch. It seems to get a bit farther now, but I get this error now:

Caused by: org.apache.maven.plugin.compiler.CompilationFailureException: Compilation failure
/C:/Development/Projects/apis/asyncapi/core/asyncapi-demo-service-api/target/generated-sources/apig
enerator/com/test/apis/asyncapi/demo/generated/types/SomeOtherObject.java:[1,63] <identif
ier> expected

When I look at my generated classes, it seems to be appending a . at the end of the package, like it's expecting 1 more package identifier. But the class is in com.test.apis.asyncapi.demo.generated.types (see line 1)

[jemacineiras]

Hi @gaby-roland,
That is odd, I added a test with your schema and generates all files property (testNestedObjectIssue). Do you mind sharing the configuration part you have in the plugin?
Cheers

[gaby-roland]

@jemacineiras Sure! Here is my plugin configuration in my pom.xml

      <plugin>
        <groupId>com.sngular</groupId>
        <artifactId>scs-multiapi-maven-plugin</artifactId>
        <version>${scs.multiapi.maven.plugin.version}</version>
        <executions>
          <execution>
            <phase>generate-sources</phase>
            <goals>
              <goal>asyncapi-generation</goal>
            </goals>
            <configuration>
              <specFiles>
                <specFile>
                  <filePath>${asyncapi.spec}</filePath>
                  <consumer>
                    <apiPackage>${project.groupId}.demo.generated.api.consumer</apiPackage>
                    <modelPackage>${project.groupId}.demo.generated.types</modelPackage>
                  </consumer>
                  <supplier>
                    <apiPackage>${project.groupId}.demo.generated.api.producer</apiPackage>
                    <modelPackage>${project.groupId}.demo.generated.types</modelPackage>
                  </supplier>
                </specFile>
              </specFiles>
            </configuration>
          </execution>
        </executions>
      </plugin>

[gaby-roland]

This is the generate code structure btw, it looks like it places SomeOtherObject outside of the schemas package:

[jemacineiras]

Thanks,

I found strange this part
<supplier> <apiPackage>${project.groupId}.demo.generated.api.producer</apiPackage> <modelPackage>${project.groupId}.demo.generated.types</modelPackage> </supplier>
But there is no producer part defined in the API definition.
That is correct?

[gaby-roland]

Yeah I think that's because I just don't have any publish operations/channels, so that package is empty right now. I just have 1 subscribe channel for now in my demo but my operational code will have both.

[jemacineiras]

Yes, that was the problem. But I think I found the key, do you mind testing this fix?

[gaby-roland]

Close, it now places the class inside the schemas package, but it seems everything is capitalized. The class name and the package, as seen in the screenshot:

This results in the other class failing to find SomeOtherObject

[gaby-roland]

With the latest changes, it seems like the supplier package and all the publish channels are completely missing.
Here is the same yaml as in the original problem, but with the added publish channel. I also updated my plugin configuration to add a <supplier> section. But the publish channels don't get generated.

asyncapi: "2.0.0"
info:
  title: Demo API
  version: "1.0.0"

channels:
  user/signedup:
    subscribe:
      operationId: emitUserSignUpEvent
      message:
        $ref : '#/components/messages/UserSignedUp'
    publish:
      operationId: onUserSignUp
      message:
        $ref: '#/components/messages/UserSignedUp'

components:
  messages:
    UserSignedUp:
      name: userSignedUp
      title: User signed up event
      summary: Inform about a new user registration in the system
      contentType: application/json
      payload:
        $ref: '#/components/schemas/userSignedUpPayload'

  schemas:
    userSignedUpPayload:
      type: object
      properties:
        firstName:
          type: string
          description: "foo"
        lastName:
          type: string
          description: "bar"
        email:
          type: string
          format: email
          description: "baz"
        createdAt:
          type: string
          format: date-time
        someOtherObject:
          type: object
          properties:
            property1:
              type: string
            property2:
              type: integer