OpenAPI Schema: SROAP00001: Model already initialized in multi-threaded builds

[janwaros]

During multi-threaded builds (-T option) on project with multiple modules containing smallrye-open-api-maven-plugin we often get errors like following (stack traces mixed due to concurrency):

        atat io.smallrye.openapi.api.OpenApiDocument.modelAlreadyInitialized[ERROR] 
java.lang.IllegalStateException: SROAP0000 io.smallrye.openapi.api.OpenApiDocument.modelAlreadyInitialized1: Model already initialized
    at io.s  (OpenApiDocumentmallrye.openapi.api.OpenApiDocumen.java:194)(OpenA
piDocument.javat.modelAlreadyInitialized:194)   (OpenApiDocument.java:194)
    at io.smallrye.openapi.api.OpenApiDocument.set (OpenApiDocument.java:187)
    at io.s
    mallrye.openap  ati.api.OpenApiDocument.modelFromAnnotationsat (Ope io.smallrye.openapi.api.OpenApiDocument.setnApiDocument.jav (OpenApiDocument.java:187)
    at io.smallrye.openapi.api.OpenApiDocument.modelFromAnnotations (OpenApiDocument.java:93)
    at io.sma io.smallryllrye.opena:93)
 api.mavenplugin.GenerateSchemaMojo.generateSchemae (Gen.openapi.api.Op   at io.smallrye.openapi.mavenplugin.GenerateSchemaMojo.generateSchemaenApiDocument.set (OpenApiDocument.java:187)
    at io.smallrye.openapi.api.OpenApiDocument.moderateSchemaMojo.java:266)
    atelFromAnnotations (Gen (OpenApiDocument.ja io.smallrye.openapi.mavenplugin.GenerateSchemaMojo.executeva:93) (GeneraterateSchemaMojo.java:241)
    at org
  .apache.maven.pleSchugin.DefaultBuildPluginManager.executeMojo  (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExec emaMojo.java:266)
    at io.sutor.executemallrye.openapi.mat io.smallrye.openapi.maveavenplug (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 orgin.Genernplugin.GenerateSchemaMojo.executeateSchemaMojo.g.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProjectenera  (GenerateSc(LifecycleModuleBuilder.java:117)
    at org.teSchemaapache.maven.hemaMojo. (Genelifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.callrateSchemaMjava:241)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojoojo.jav (DefaultBuildPluginManager.java:137)
    at org (MultiThreadedBuilder.java:190)
    at org.apache.ma.apache.maven.lifecycle.internal.MojoExecutor.executea :266)
    at io.smallrye.openapi.mavenplugin.GenerateSchemaMojo.executev (GeenerateSch(MojoExecutor.java:210)emaMojo.java:241)n.lifecycl
  
      at oe.internal.builder.multithreaded.MultiThreadedBurg.apache.maven.lifecycle.interat 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.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:190)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:186)
    at java.util.concurrent.FutureTask.run (FutureTask.java:266)
    at java.util.concurrent.Executorsnal.MojoExecutor.executeilder$1.call (Moj$RuoExecutor.jannv (MultiTa:156ableAdap)
    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.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:190)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:186)
    at java.util.concurrent.FutureTask.run (FutureTask.java:266)
    at java.util.concurrent.Executors$RunnableAdapter.call (Executors.java:511)
    at java.util.concurrent.FutureTask.run (FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:624)
    at java.lang.Thread.run (Thread.java:748)```
It looks like there is some kind of race condition happening when two modules are trying to generate documentation at the same time.