[QUESTION] [JAVA] possible bug openapi-generator-maven-plugin handling of different discriminator values mapping to the same schema

Hello, I have the following problem as of 7.14.0, which is also present on the latest master. The issue is not present in 7.13.0 and earlier.

Here is my snippet:

      responses:
        '200':
          description: "List of all the objects."
          content:
            application/json:
              schema:
                type: array
                items:
                  oneOf:
                    - $ref: '#/components/schemas/TypeA'
                    - $ref: '#/components/schemas/TypeB'
                  discriminator:
                    propertyName: discriminatorProperty
                    mapping:
                      ONE: '#/components/schemas/TypeA'
                      TWO: '#/components/schemas/TypeB'
                      THREE: '#/components/schemas/TypeB'
                      FOUR: '#/components/schemas/TypeB'
                      FIVE: '#/components/schemas/TypeB'

When trying to generate openapi controllers and api objects I get the following error:

java.lang.IllegalStateException: Duplicate key #/components/schemas/TypeB (attempted merging values TWO and THREE)
    at java.util.stream.Collectors.duplicateKeyException (Collectors.java:135)
    at java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1 (Collectors.java:182)
    at java.util.stream.ReduceOps$3ReducingSink.accept (ReduceOps.java:169)
    at java.util.Iterator.forEachRemaining (Iterator.java:133)
    at java.util.Spliterators$IteratorSpliterator.forEachRemaining (Spliterators.java:1939)
    at java.util.stream.AbstractPipeline.copyInto (AbstractPipeline.java:509)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto (AbstractPipeline.java:499)
    at java.util.stream.ReduceOps$ReduceOp.evaluateSequential (ReduceOps.java:921)
    at java.util.stream.AbstractPipeline.evaluate (AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.collect (ReferencePipeline.java:682)
    at io.swagger.v3.parser.processors.ExternalRefProcessor.processSchema (ExternalRefProcessor.java:253)
    at io.swagger.v3.parser.processors.ExternalRefProcessor.processSchema (ExternalRefProcessor.java:244)
    at io.swagger.v3.parser.processors.ExternalRefProcessor.processRefSchemaObject (ExternalRefProcessor.java:1009)
    at io.swagger.v3.parser.processors.ExternalRefProcessor.processPathItem (ExternalRefProcessor.java:350)
    at io.swagger.v3.parser.processors.ExternalRefProcessor.processRefToExternalPathItem (ExternalRefProcessor.java:325)
    at io.swagger.v3.parser.processors.PathsProcessor.processReferencePath (PathsProcessor.java:346)
    at io.swagger.v3.parser.processors.PathsProcessor.processPaths (PathsProcessor.java:68)
    at io.swagger.v3.parser.OpenAPIResolver.resolve (OpenAPIResolver.java:72)
    at io.swagger.v3.parser.OpenAPIResolver.resolve (OpenAPIResolver.java:59)
    at io.swagger.v3.parser.OpenAPIV3Parser.resolve (OpenAPIV3Parser.java:240)
    at io.swagger.v3.parser.OpenAPIV3Parser.readContents (OpenAPIV3Parser.java:183)
    at io.swagger.v3.parser.OpenAPIV3Parser.readLocation (OpenAPIV3Parser.java:97)
    at io.swagger.parser.OpenAPIParser.readLocation (OpenAPIParser.java:16)
    at org.openapitools.codegen.config.CodegenConfigurator.toContext (CodegenConfigurator.java:687)
    at org.openapitools.codegen.config.CodegenConfigurator.toClientOptInput (CodegenConfigurator.java:745)
    at org.openapitools.codegen.plugin.CodeGenMojo.execute (CodeGenMojo.java:972)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)

Is this expected? Can I avoid this in some other way, except creating TypeC, TypeD etc?

Reproduce the supplied discriminator mapping with openapi-generator-maven-plugin 7.13.0, 7.14.0, and current master. Start at CodegenConfigurator.toContext and the swagger parser's ExternalRefProcessor.processSchema, then trace how duplicate mappings to TypeB are collected. Done means the specification generates successfully without requiring separate schemas for each discriminator value.