Invalid Java is generated from swagger (2.0) - copying definition names with « »

Description

Java generator generates invalid java code where swagger-codegen succeeded. openapi codegen produces from definition ResultList«GenericRow»-> ResultListGenericRowresultList«GenericRow» =

openapi-generator version

4.3.1 with maven plugin

OpenAPI declaration file content or url

{
	"swagger": "2.0",
	"info": {
		"description": "Api Documentation",
		"version": "1.0",
		"title": "Api Documentation",
		"termsOfService": "urn:tos",
		"contact": {
			
		},
		"license": {
			"name": "Apache 2.0",
			"url": "http://www.apache.org/licenses/LICENSE-2.0"
		}
	},
	"securityDefinitions": {
		"basicAuth": {
			"type": "basic"
		}
	},
	"security": [
		{
			"basicAuth": []
		}
	],
	"host": "example.com",
	"basePath": "/api",
	"tags": [
	],
	"paths": {
	},
	"definitions": {
		"GenericRow": {
			"type": "object",
			"title": "GenericRow",
			"additionalProperties": {
				"type": "object"
			}
		},
		"ResultList«GenericRow»": {
			"type": "object",
			"properties": {
				"offset": {
					"type": "integer",
					"format": "int64"
				},
				"overallCount": {
					"type": "integer",
					"format": "int64"
				},
				"results": {
					"type": "array",
					"items": {
						"$ref": "#/definitions/GenericRow"
					}
				}
			},
			"title": "ResultList«GenericRow»"
		}
	}
}

Command line used for generation

        <plugin>
            <groupId>org.openapitools</groupId>
            <artifactId>openapi-generator-maven-plugin</artifactId>
            <version>4.3.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>generate</goal>
                    </goals>
                    <configuration>
                        <generateApiTests>false</generateApiTests>
                        <generateModelTests>false</generateModelTests>
                        <generateSupportingFiles>false</generateSupportingFiles>
                        <environmentVariables>
                            <supportingFiles>
                                ApiClient.java,Authentication.java,OAuth.java,ApiKeyAuth.java,HttpBasicAuth.java,RFC3339DateFormat.java
                            </supportingFiles>
                        </environmentVariables>
                        <inputSpec>${project.basedir}/src/main/resources/api-tpz.json</inputSpec>
                        <generatorName>java</generatorName>
                        <configOptions>
                            <library>resttemplate</library>
                            <dateLibrary>java8</dateLibrary>
                        </configOptions>
                    </configuration>
                </execution>
            </executions>
        </plugin>

Steps to reproduce

• set up maven java project
• add given plugin setting
• put api spec in file /src/main/resources/api-tpz.json
• run mvn compile

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/issues/1137

Suggest a fix/enhancement

a generator should never generate invalid code. Either it generates valid code or it errors out.
For me it would be sufficient to have a workaround. the swagger is given i could not regenerate. i need only a valid client.

Regarding file name and class the special character are handled correctly -> ResultListGenericRow is generated. The problem only occurs from variable names of that type -> resultList«GenericRow»

the part that handles these special characters for generating file names could be reused for generating variable names?!

Start by reproducing the provided Swagger 2.0 definition with the openapi-generator Maven plugin and Java generator. Compare the valid ResultListGenericRow class name with the generated resultList«GenericRow» variable, then verify that the generated client compiles with valid Java identifiers.