[BUG][Java][Spring] Multiple "tags" parameters in @Operation annotation

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• 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

The OpenAPI generator generates invalid Java SpringBoot code if multiple tags are used in the OpenAPI definition. The generated @Operation annotation contains all the tags multiple times, depending on how many tags are present.

Here is an example:

    @Operation(
        operationId = "dummyoperation",
        tags = { "tag1", "tag2" },
        tags = { "tag1", "tag2" }, // <- this is the invalid duplicate
        responses = {
            @ApiResponse(responseCode = "200", description = "successful operation")
        }
    )

This is generated with the latest stable version 5.4.0. We are using spring-boot generator. This is an example project, which demonstrates the error: maven-openapi-generator-poc.zip

OpenAPI declaration file

openapi: 3.0.1
info:
  description: Proof of error
  title: Proof of error
  version: 0.0.1
servers:
- url: http://localhost:8090/api/v1
- url: https://localhost:8090/api/v1
paths:
  /dummy:
    post:
      operationId: dummyoperation
      responses:
        "200":
          content: {}
          description: successful operation
      tags:
        - tag1
        - tag2

Maven project description

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>maven-openapi-generator-poc</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.3</version>
        <relativePath/>
    </parent>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>io.swagger.core.v3</groupId>
            <artifactId>swagger-annotations</artifactId>
            <version>2.1.12</version>
        </dependency>
        <dependency>
            <groupId>org.openapitools</groupId>
            <artifactId>jackson-databind-nullable</artifactId>
            <version>0.2.2</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-yaml</artifactId>
            <version>2.13.1</version>
        </dependency>
        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>2.0.1.Final</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <version>5.4.0</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>src/main/resources/openapi.yaml</inputSpec>
                            <generatorName>spring</generatorName>
                            <configOptions>
                                <interfaceOnly>false</interfaceOnly>
                                <basePackage>org.example.base</basePackage>
                                <configPackage>org.example.config</configPackage>
                            </configOptions>
                            <library>spring-boot</library>
                            <output>${project.build.directory}/generated-sources</output>
                            <apiPackage>org.example.api</apiPackage>
                            <modelPackage>org.example.model</modelPackage>
                            <invokerPackage>org.example.invoke</invokerPackage>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

Generation Details

• Maven SpringBoot project

Steps to reproduce

• mvn clean compile in the attached example project maven-openapi-generator-poc.zip. The error is located in the generated DummyApi.java.

[wing328]

@apr4 can you please try the latest master? We just merged a PR related to multiple “tags” for the spring generator.

[GregDThomas]

A workaround is to download the template in the PR at https://github.com/OpenAPITools/openapi-generator/pull/13434 and place a copy locally in a folder called JavaSpring, and specify it when generating code as described at https://openapi-generator.tech/docs/templating/

e.g. -t (wherever)\templates\JavaSpring

Hopefully the PR will be accepted and in a release soon 🤞