[BUG][SPRING] Deprecated MappingJackson2HttpMessageConverter for RestClient generator

[faltfe]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

After upgrading the openapi-generator-maven-plugin to 7.20.0 I tried the new options useJackson3 and useSpringBoot4 (see #22854)
I still get the messages

• [removal] MappingJackson2HttpMessageConverter in org.springframework.http.converter.json is deprecated and marked for removal
• [removal] messageConverters(Consumer<List<HttpMessageConverter<?>>>) in Builder is deprecated and marked for removal

openapi-generator version

7.20.0

OpenAPI declaration file content or url

Generation Details

<plugin>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-maven-plugin</artifactId>
    <version>7.20.0</version>
    <executions>
        <execution>
            <id>generate-client</id>
            <goals>
                <goal>generate</goal>
            </goals>
            <phase>generate-resources</phase>
            <configuration>
                <inputSpec>
                    ${project.build.directory}/generated-resources/src/main/resources/api/openapi.yaml
                </inputSpec>
                <generatorName>java</generatorName>
                <configOptions>
                    <library>restclient</library>
                    <useJakartaEe>true</useJakartaEe>
                    <dateLibrary>java8</dateLibrary>
                    <useJackson3>true</useJackson3>
                    <useSpringBoot4>true</useSpringBoot4>
                    <implicitHeaders>true</implicitHeaders>
                    <invokerPackage>faltfe.service</invokerPackage>
                    <configPackage>faltfe.config</configPackage>
                    <apiPackage>faltfe.api</apiPackage>
                    <modelPackage>faltfe.model</modelPackage>
                </configOptions>
                <generateModelTests>false</generateModelTests>
                <generateApiTests>false</generateApiTests>
            </configuration>
        </execution>
    </executions>
</plugin>

With the java configuration

@Configuration
@RequiredArgsConstructor
public class IamsConfiguration {

    private final ArmsProperties armProperties;

    @Bean
    public ApiClient apiClient() {
        var apiClient = new CustomApiClient().apiClient();
        apiClient.setBasePath("http://localhost:8000");
        return apiClient;
    }

    @Bean
    public UserApi userApi(ApiClient apiClient) {
        return new UserApi(apiClient);
    }

    private class CustomApiClient extends ApiClient {

        ApiClient apiClient() {
            var restClient = this.restClient.mutate().requestInterceptor((request, body, execution) -> {
                request.getHeaders().add("tenant", "Foobar");
                return execution.execute(request, body);
            });
            return new ApiClient(restClient.build());
        }
    }
}

Steps to reproduce

Generate any YAML input spec the see the log messages from Maven. There are at least two warnings about the deprections.

Related issues/PRs

#22854

Suggest a fix

I would expect that there is no warning when using Jackson3.

[faltfe]

Btw., the documentation appears to be unchanged since version 7.20.0
https://github.com/OpenAPITools/openapi-generator/blob/master/docs/generators/java.md Jackson 3 is not mentioned there

[Picazsoo]

I see in your config: <generatorName>java</generatorName>

The issue title mentions spring and yet you are using java generator in your config.

I am quite certain that the functionality has been implemented only in the java-spring codegen (commonly refered to in the issues as java-spring to differentiate it from kotlin-spring). And I can see jackson3 mentioned in the docs: https://github.com/OpenAPITools/openapi-generator/blob/master/docs/generators/spring.md

So if you want to use it, you should do: <generatorName>spring</generatorName>

[faltfe]

Thanks for your response. As I want to generate a client not a server from the API spec I currently use the <library>restclient</library> which generates a Spring client. Therefore, I guess, it is not a bug it is a feature request to support Spring Boot 4 and Jackson 3 with the RestClient.

[Picazsoo]

Have you considered going the spring http declarative interface route? (available in spring generator as spring-http-interface library). If it is suitable for your needs, you can use it easily with RestClient.

And regarding the support in java generator - I presume it will come in due time. Someone will have to implement it once they feel the need for it. You could be that someone (-:

Just to make it clear - I am not a maintainer of this project. We just use it extensively at our company and I am compelled to give back at least a little.

[faltfe]

I try to change the generator to spring with <library>spring-http-interface</library>. Unfortunately, it fails with <useSpringBoot4>true</useSpringBoot4> because of missing imports in the generated Api classes.

    @HttpExchange(
        method = "GET",
        value = "/groups/contains",
        accept = { "application/json", "application/problem+json" }
    )
    ResponseEntity<List<UserGroupMembership>> checkUserMembership(
        @Parameter(name = "userIds", description = "Hello world", required = true, in = ParameterIn.QUERY) @RequestParam(value = "userIds", required = true) List<String> userIds,
        @Parameter(name = "groupFilter", description = "", in = ParameterIn.QUERY) @Nullable UserGroupFilter groupFilter
    );

Imports are missing for

• @Parameter
• @ParameterIn

I also tested <annotationLibrary>swagger2</annotationLibrary> and without <useSpringBoot4>true</useSpringBoot4> . The result was always an compilation error caused by missing imports. Manually importing is possible.

When I use <useSpringBoot3>true</useSpringBoot3> the generation fails as well with the error:

java.lang.RuntimeException: Could not generate supporting file 'SupportingFile[templateFile='pom-sb3.mustache', folder='', destinationFilename='pom.xml', canOverwrite=true]'
at org.openapitools.codegen.DefaultGenerator.generateSupportingFiles (DefaultGenerator.java:1104)
at org.openapitools.codegen.DefaultGenerator.generate (DefaultGenerator.java:1301)
at org.openapitools.codegen.plugin.CodeGenMojo.execute (CodeGenMojo.java:1005)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)
at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:906)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:283)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:104)
at java.lang.reflect.Method.invoke (Method.java:565)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:255)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:201)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:361)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:314)
Caused by: org.openapitools.codegen.templating.TemplateNotFoundException: pom-sb3.mustache
at org.openapitools.codegen.TemplateManager.getFullTemplateFile (TemplateManager.java:60)
at org.openapitools.codegen.TemplateManager.getFullTemplateContents (TemplateManager.java:78)
at org.openapitools.codegen.templating.MustacheEngineAdapter.compileTemplate (MustacheEngineAdapter.java:68)
at org.openapitools.codegen.TemplateManager.write (TemplateManager.java:167)
at org.openapitools.codegen.DefaultGenerator.processTemplateToFile (DefaultGenerator.java:1450)
at org.openapitools.codegen.DefaultGenerator.processTemplateToFile (DefaultGenerator.java:1430)
at org.openapitools.codegen.DefaultGenerator.generateSupportingFiles (DefaultGenerator.java:1096)
at org.openapitools.codegen.DefaultGenerator.generate (DefaultGenerator.java:1301)
at org.openapitools.codegen.plugin.CodeGenMojo.execute (CodeGenMojo.java:1005)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)
at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:906)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:283)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:104)
at java.lang.reflect.Method.invoke (Method.java:565)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:255)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:201)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:361)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:314)

[Picazsoo]

Ok, let me check this. I remember this being tricky.

[Picazsoo]

can you try to set documentationProvider to none?

[alex-nt]

Maybe this will help? #23023

[faltfe]

can you try to set documentationProvider to none?

With documentProvider set to none the code compiles. The only problem is now that the generates methods return ResponseEntity<Object> instead of Object like before with RestClient. But I can refactor this.

Maybe this will help? #23023

That looks promising. I'm looking forward to test it in the next release.

[Picazsoo]

try setting "useResponseEntity" to "false" in additional properties

[faltfe]

try setting "useResponseEntity" to "false" in additional properties

Using useResponseEntity as configOption is working

<generatorName>spring</generatorName>
<configOptions>
    <library>spring-http-interface</library>
    <useJackson3>true</useJackson3>
    <useSpringBoot4>true</useSpringBoot4>
    <openApiNullable>false</openApiNullable>
    <documentationProvider>none</documentationProvider>
    <useResponseEntity>false</useResponseEntity>
    <implicitHeaders>true</implicitHeaders>
</configOptions>

Maven builds the project successfully but I have an issue with exploded parameters.

I have OpenAPI definition like

get:
      tags:
        - user
      summary: List all users
      description: Returns a list of all known users.
      operationId: getAllUsers
      parameters:
        - $ref: './schemas/schemas.yaml#/components/parameters/UserFilterParam'
        - $ref: './schemas/schemas.yaml#/components/parameters/UserGroupFilterParam'
        - $ref: './schemas/schemas.yaml#/components/parameters/UserPageParam'
        - $ref: './schemas/schemas.yaml#/components/parameters/UserSortParam'

They are all defined like

    UserGroupFilterParam:
      name: groupFilter
      in: query
      style: form
      explode: true
      required: false
      schema:
        $ref: "#/components/schemas/UserGroupFilter"

The generated code

    @ResponseStatus(HttpStatus.OK)
    @HttpExchange(
        method = "GET",
        value = "/users",
        accept = { "application/json", "application/problem+json" }
    )
    List<User> getAllUsers(
         @Nullable UserFilter userFilter,
         @Nullable UserGroupFilter groupFilter,
         @Nullable UserPage userPage,
         @Nullable UserSort userSort
    );

When I run a request again the generated API client I get an error because the object is not exloded like before with the RestClient. As I'm new to HTTP interfaces with Spring Boot, I'm not sure yet, if it is a configuration issue or if there is something missing in the generated files. The exception is that there is no resolver for parameter [0].

[Picazsoo]

Hi @faltfe , since the fix is merged in #23023, I guess you can close this? Or are you waiting to really test it before closing the issue? Makes sense - just asking.

[faltfe]

I would like to wait for a release to test this. Otherwise, you can close it, when this is your workflow in this project. I will open a new issue when the problem is not solved in the next release.

[Picazsoo]

Makes sense to keep it open. The release is just days from now anyways.