NullPointerException in Studio (14.0-202) when creating Recursive/Hierarchical Property

Support
#1

Hi, I’m not sure if I’m doing something wrong, or there is an issue with the current release (14.0-202) of CUBA Studio, but when I create an attribute (either in code, or in the Entity designer, that is based on the current Entity (forming a hierarchical relationship), I get a NullPointerException in Studio as below.

My code looks like this:

     @OnDeleteInverse(DeletePolicy.CASCADE)
     @OnDelete(DeletePolicy.DENY)
     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(name = "PARENT_ID")
     private MyEntity parent;

     public MyEntity getParent() {
         return parent;
     }

     public void setParent(MyEntity parent) {
         this.parent = parent;
    }

Is this something that I am doing wrong, or an issue with Studio?

Thanks.

java.lang.StackOverflowError
	at com.intellij.extapi.psi.StubBasedPsiElementBase.isValid(StubBasedPsiElementBase.java:272)
	at com.intellij.psi.impl.smartPointers.SmartPsiElementPointerImpl.getElement(SmartPsiElementPointerImpl.java:91)
	at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:851)
	at com.haulmont.studio.backend.util.MetadataUtil.ra(MetadataUtil.java:963)
	at com.haulmont.studio.backend.model.EntityPsi.getPsiClass(EntityPsi.java:465)
	at com.haulmont.studio.backend.model.EntityPsi.lambda$getFqn$15(EntityPsi.java:309)
	at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:851)
	at com.haulmont.studio.backend.util.MetadataUtil.ra(MetadataUtil.java:963)
	at com.haulmont.studio.backend.model.EntityPsi.getFqn(EntityPsi.java:309)
	at com.haulmont.studio.backend.model.Entity.hashCode(Entity.java:493)
	at com.haulmont.studio.backend.model.View.hashCode(View.java:193)
	at java.base/java.util.Arrays.hashCode(Arrays.java:4685)
	at java.base/java.util.Objects.hash(Objects.java:146)
	...
#3

Hi, Richard!

Unfortunately I can’t reproduce the issue.
Could you please attach idea.log file? (Help -> Show Log in Explorer)
Also a small test project in which you can reproduce the problem could also be very helpful.

#4

I tried to recreate the issue in a new project and seemingly couldn’t, and then returned to the existing project (where I had previously commented out the offending code) and couldn’t recreate it either. It took a fair bit of head scratching to realise what was different and how to reproduce.

The issue was that I had set the name pattern to be cyclic @NamePattern("%s > %s|description,parent") which the GUI editor permitted, but is clearly unsupported. So this seems to be something that the editor should prevent, but also not crash if you do in code.

I assume that, given the error, there is no way of using the parent’s name as part of the child’s display name?

#5

Thanks for providing all details.
The YouTrack issue was created.

You are right, parent attribute can’t be added to the name pattern. Name pattern is used to form _minimal view, but views cannot have cyclic references.
As a workaround you can store parent name in a separate attribute and update it using EntityChangedEvent each time parent changed. This attribute can be safely added to the name pattern.