[BUG] openapi-generator mvn plugin - typeMappings does not appear to take hold in individual executions

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• 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?
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Description

We use the maven plugin to generate our artefacts.
I was setting up type mappings in my executions so that int32 types were mapped to long instead of Integer:

    <execution>
      <id>myserver-me-api</id>
      <goals>
        <goal>generate</goal>
      </goals>
      <configuration>
        <inputSpec>${project.basedir}/src/main/resources/myserver-me-api.json</inputSpec>
        <generateApiTests>false</generateApiTests>
        <generateModelTests>false</generateModelTests>
        <generatorName>java</generatorName>
        <configOptions>
          <sourceFolder>com/myserver/api</sourceFolder>
          <apiPackage>client.myserver</apiPackage>
          <modelPackage>client.myserver.model</modelPackage>
          <invokerPackage>client.myserver.handler</invokerPackage>
          <library>resttemplate</library>
          <java8>true</java8>
          <importMappings>integer=Long</importMappings>
          <typeMappings>integer=Long,int=Long</typeMappings>
          <dateLibrary>java8-localdatetime</dateLibrary>
          <serializableModel>true</serializableModel>
        </configOptions>
      </configuration>
    </execution>

However it had no effect and my generated POJO still used Integer here. However, defining typeMappings in the plugin section did work:

  <plugin>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-maven-plugin</artifactId>
    <version>5.1.0</version>
    <configuration>
      <typeMappings>integer=Long,int=Long</typeMappings>
    </configuration>
    <executions>
        ...

Is this a feature-not-a-bug kind of thing or are we supposed to be able to configure the individual executions this way? The openapi-generator-maven-plugin markdown document is not very clear on the distinction so I am unsure.

openapi-generator version

Using 5.1.0 of openapi-generator-maven-plugin

OpenAPI declaration file content or url

Generation Details

Steps to reproduce

<build>
<plugins>
<plugin>
<groupId>org.openapitools</groupId>
<artifactId>openapi-generator-maven-plugin</artifactId>
<version>5.1.0</version>
<configuration>
	<typeMappings>integer=Long,int=Long</typeMappings> <!-- this works -->
</configuration>
<executions>
	<execution>
	<id>myapp-me-api</id>
	<goals>
		<goal>generate</goal>
	</goals>
	<configuration>
		<inputSpec>${project.basedir}/src/main/resources/myapp-me-api.json</inputSpec>
		<generateApiTests>false</generateApiTests>
		<generateModelTests>false</generateModelTests>
		<generatorName>java</generatorName>
		<configOptions>
		<sourceFolder>com/myapp/api</sourceFolder>
		<apiPackage>client.myapp</apiPackage>
		<modelPackage>client.myapp.model</modelPackage>
		<invokerPackage>client.myapp.handler</invokerPackage>
		<library>resttemplate</library>
		<java8>true</java8>
		<typeMappings>integer=Long,int=Long</typeMappings> <!-- this don't -->
		<dateLibrary>java8-localdatetime</dateLibrary>
		<serializableModel>true</serializableModel>
		</configOptions>
	</configuration>
	</execution>
</executions>
</plugin>
</plugins>
</build>

Related issues/PRs

Suggest a fix

Start with the openapi-generator-maven-plugin configuration and its handling of plugin-level versus execution-level parameters. Reproduce the Maven build using the provided execution configuration and compare the generated Java POJO when typeMappings is placed in each location. Done means the supported configuration behavior is clear and the execution-level mapping either takes effect or is documented as unsupported.