Creating own IntelliJ Plugin causes Read access is allowed from inside read-action

Question

I'm creating an IntelliJ Plugin and I want to use the Modal ProgressIndicator.

Now, if I don't use the Modal ProgressIndicator everything goes through without error.
If I do use the Modal ProgressIndicator I get the stack trace down below (bottom).

Ok, what is the triggering moment?
I managed to figure out that every line of code marked as the same error seems to be whenever I try to access or read from a Psi-Object (PsiElement, PsiAnnotation and so on...)

Code without:

  @Override
  public void actionPerformed(@NotNull AnActionEvent e) {
    if (new CreationWindowWrapper(true).showAndGet()) {
      loadAndInit();
    }
  }

Code with:

  @Override
  public void actionPerformed(@NotNull AnActionEvent e) {
    if (new CreationWindowWrapper(true).showAndGet()) {
      var project = ProjectManager.getInstance().getOpenProjects()[0];
      var modalTask = new Modal(project, "Copying Case", true) {
        public void run(@NotNull() final ProgressIndicator indicator) {
          loadAndInit(indicator);
        }
      };
      ApplicationManager.getApplication().invokeLater(() -> ProgressManager.getInstance().run(modalTask));
    }
  }

StackTrace:

java.lang.Throwable: Read access is allowed from inside read-action (or EDT) only (see com.intellij.openapi.application.Application.runReadAction())
    at com.intellij.openapi.diagnostic.Logger.error(Logger.java:200)
    at com.intellij.openapi.application.impl.ApplicationImpl.assertReadAccessAllowed(ApplicationImpl.java:980)
    at com.intellij.psi.impl.source.tree.TreeElement.assertReadAccessAllowed(TreeElement.java:424)
    at com.intellij.psi.impl.source.tree.SharedImplUtil.findFileElement(SharedImplUtil.java:79)
    at com.intellij.psi.impl.source.tree.SharedImplUtil.getContainingFile(SharedImplUtil.java:54)
    at com.intellij.psi.impl.source.tree.CompositePsiElement.getContainingFile(CompositePsiElement.java:90)
    at com.intellij.psi.impl.ResolveScopeManager.getElementResolveScope(ResolveScopeManager.java:34)
    at com.intellij.psi.impl.source.tree.CompositePsiElement.getResolveScope(CompositePsiElement.java:241)
    at com.intellij.psi.impl.file.PsiPackageImpl.processDeclarations(PsiPackageImpl.java:297)
    at com.intellij.psi.impl.source.PsiJavaFileBaseImpl.processPackageDeclarations(PsiJavaFileBaseImpl.java:451)
    at com.intellij.psi.impl.source.PsiJavaFileBaseImpl.processOnDemandTarget(PsiJavaFileBaseImpl.java:461)
    at com.intellij.psi.impl.source.PsiJavaFileBaseImpl.processImplicitImports(PsiJavaFileBaseImpl.java:428)
    at com.intellij.psi.impl.source.PsiJavaFileBaseImpl.processOnDemandPackages(PsiJavaFileBaseImpl.java:381)
    at com.intellij.psi.impl.source.PsiJavaFileBaseImpl.processDeclarations(PsiJavaFileBaseImpl.java:301)
    at com.intellij.psi.scope.util.PsiScopesUtil.treeWalkUp(PsiScopesUtil.java:61)
    at com.intellij.psi.scope.util.PsiScopesUtil.treeWalkUp(PsiScopesUtil.java:40)
    at com.intellij.psi.scope.util.PsiScopesUtil.resolveAndWalk(PsiScopesUtil.java:207)
    at com.intellij.psi.scope.util.PsiScopesUtil.resolveAndWalk(PsiScopesUtil.java:136)
    at com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl.resolve(PsiJavaCodeReferenceElementImpl.java:495)
    at com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl.access$100(PsiJavaCodeReferenceElementImpl.java:44)
    at com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl$OurGenericsResolver.resolve(PsiJavaCodeReferenceElementImpl.java:381)
    at com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl$OurGenericsResolver.resolve(PsiJavaCodeReferenceElementImpl.java:374)
    at com.intellij.psi.impl.source.resolve.ResolveCache.lambda$resolveWithCaching$2(ResolveCache.java:184)
    at com.intellij.openapi.util.Computable.get(Computable.java:18)
    at com.intellij.psi.impl.source.resolve.ResolveCache.lambda$loggingResolver$4(ResolveCache.java:260)
    at com.intellij.openapi.util.RecursionManager$1.computePreventingRecursion(RecursionManager.java:114)
    at com.intellij.openapi.util.RecursionGuard.doPreventingRecursion(RecursionGuard.java:44)
    at com.intellij.openapi.util.RecursionManager.doPreventingRecursion(RecursionManager.java:68)
    at com.intellij.psi.impl.source.resolve.ResolveCache.resolve(ResolveCache.java:237)
    at com.intellij.psi.impl.source.resolve.ResolveCache.resolveWithCaching(ResolveCache.java:184)
    at com.intellij.psi.impl.PsiImplUtil.multiResolveImpl(PsiImplUtil.java:789)
    at com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl.getCanonicalText(PsiJavaCodeReferenceElementImpl.java:296)
    at com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl.getCanonicalText(PsiJavaCodeReferenceElementImpl.java:280)
    at com.intellij.psi.impl.source.tree.java.PsiAnnotationImpl.getQualifiedName(PsiAnnotationImpl.java:77)
    at com.intellij.psi.impl.PsiImplUtil.findAnnotation(PsiImplUtil.java:296)
    at com.intellij.psi.impl.source.PsiModifierListImpl.findAnnotation(PsiModifierListImpl.java:311)
    at com.intellij.psi.PsiJvmConversionHelper.getListAnnotation(PsiJvmConversionHelper.java:53)
    at com.intellij.psi.PsiModifierListOwner.getAnnotation(PsiModifierListOwner.java:41)
    at com.intellij.psi.PsiJvmModifiersOwner.getAnnotation(PsiJvmModifiersOwner.java:27)
    at se.tvv.insertionextractor.extractors.ValueExtractor.getElementValue(ValueExtractor.java:82)
    at se.tvv.insertionextractor.converter.FieldMapper.createSimpleColumnField(FieldMapper.java:71)
    at se.tvv.insertionextractor.converter.FieldMapper.mapField(FieldMapper.java:44)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
    at java.base/java.util.stream.ReferencePipeline$11$1.accept(ReferencePipeline.java:442)
    at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
    at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
    at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578)
    at se.tvv.insertionextractor.converter.FieldMapper.getClassFields(FieldMapper.java:35)
    at se.tvv.insertionextractor.extractors.Extractor.initiateCopyOfObject(Extractor.java:36)
    at se.tvv.insertionextractor.extractors.Extractor.init(Extractor.java:30)
    at se.tvv.insertionextractor.MainAction.loadAndInit(MainAction.java:63)
    at se.tvv.insertionextractor.MainAction$1.run(MainAction.java:50)

I have tried the following google result actions:

SwingUtils.invokeLater(ProgressManager.getInstance().run(modalTask))

ApplicationManager.getApplication().invokeLaterOnWriteThread(ProgressManager.getInstance().run(modalTask))

Answer 1

Nevermind, I solved it by myself :P

@Override
  public void actionPerformed(@NotNull AnActionEvent e) {
    if (new CreationWindowWrapper(true).showAndGet()) {
      var project = ProjectManager.getInstance().getOpenProjects()[0];
      var modalTask = new Modal(project, "Copying Case", true) {
        public void run(@NotNull() final ProgressIndicator indicator) {
          ApplicationManager.getApplication().runReadAction(() -> loadAndInit(indicator));
        }
      };
      ApplicationManager.getApplication().invokeLater(() -> ProgressManager.getInstance().run(modalTask));
    }
  }