Missing relationship with projection

[Marc-AntoineGL]

Hello,

Spring version: 2.7.11
spring-boot-starter-data-neo4j: 2.7.11

(At the moment we stay on version 2 but will upgrade as soon as possible)

I am using repositories methods with some projections and on some cases i'm getting some empty attributes in some nodes containing relationships. I'll try to explain as clear as possible the case where i'm getting this.
(The short answer is that I'm getting the wrong collectionName inside the DefaultNeo4jEntityConverter class at the line "Value list = values.get(collectionName)", I will come back to it later)

In my project I have ParentA, ParentB and ParentC classes. They are linked by relationships like that

//ParentA class
@Relationship(type = "HasBs", direction = Direction.OUTGOING)
private ParentB parentB; 

//ParentB class
@Relationship(type = "HasCs", direction = Direction.OUTGOING)
private ParentC parentC; 

I have some inheritance with my nodes. I have ChildA, ChildB, ChildC classes (extending the parent ones);
I have a simple generated repository method findById(Long id, Class<?> projClazz).
When calling this method i'm using kind of nested projection like that

//ChildA repository
ChildAProjection {
    ChildBProjection getParentB();
}

//ChildB repository
ChildBProjection {
   ChildCProjection getParentC();
}

So, now I would like to get my ChildA node with the relationships defined in the child & parent classes. I perform a call like this:

ChildAProjection proj = childARepository.findById(new Long(1), ChildAProjection.class)

With that, in my "proj" variable, I can perfectly find the parentB attribute filled correctly, but regarding the parentC of the parentB attribute, it is null.

What I've noted when trying to debug in your library is that when you're parsing the Record sent by neo4j, you have some "Node_Relation_Node" strings. And that's what is causing the trouble in my case, i'll try to explain.

In the record sent by neo4j for the execution of my request. I have something like

[...]ChildA_HasBs_ParentB: [{__internalNeo4jId__: 1, ParentB_HasCs_ParentC[...]

For the first relation, the collectionName in

//DefaultNeo4jEntityConverter 
String collectionName = relationshipDescription.generateRelatedNodesCollectionName(genericNodeDescription);

is correct because it's "ChildA_HasBs_ParentB" but in the second relation (deeper relation), there is a mistake because the collectionName is "ChildB_HasCs_ParentC" so it doesn't find it in the Record...

So in the end, my ChildA has the ChildB attribute, but this later one doesn't have the ChildC attribute filled.

[meistermeier]

Thanks for bringing this to our attention. This is indeed buggy around the detection of the right base type to determine the relationship name that is meant to connect the nodes.
There is now a fix that I will port into a 6.3. preview branch tomorrow for you to test.

[meistermeier]

There is now a 6.3.14-GH-2819-SNAPSHOT available. If you want to give us feedback on the fix.

[Marc-AntoineGL]

Ok thanks I will try to test that as soon as possible and I will let you know.

[Marc-AntoineGL]

Just a nooby question maybe, sorry, but where exactly can I find this snapshot ? 😅

[meistermeier]

Not a problem at all, typically I attach also the maven repositories when I mention a SNAPSHOT version. So it's also my bad.

<repositories>
  <repository>
    <id>spring-milestones</id>
    <name>Spring Milestones</name>
    <url>https://repo.spring.io/milestone</url>
    <snapshots>
      <enabled>false</enabled>
    </snapshots>
  </repository>
  <repository>
    <id>spring-snapshots</id>
    <name>Spring Snapshots</name>
    <url>https://repo.spring.io/snapshot</url>
    <releases>
      <enabled>false</enabled>
    </releases>
  </repository>
</repositories>

[meistermeier]

Any update on this?
I will merge this now into the development branches because next release day is on Friday.
Note: Spring Boot 2.7 and with this Spring Data 6.3 got its last official OSS patch release last month. Even though I will also merge this into 6.3 there won't be any planned upcoming release anymore. https://spring.io/projects/spring-boot#support

[Marc-AntoineGL]

Hello, sorry for late I had some end of the year devs rush...

I just tested it now and it works like a charm for me !
I was testing it with 3 levels of inheritance and with a 4 relationships projection depth.
I think that's not too much of a test but I guess if it work for these, it will work for N levels.

Regarding the next release subject you noted, does it mean the current 2.7.18 will then use your next "6.3.19" (I guess ?) you plan to release on friday ? And this "6.3.19" will be the last version you will release for the 6.3.x versions ? Or am I mistaken ?

Another question regarding this issue you fixed. Was it also present on the 7.x.x versions ? Or did you fix exclusively for the 6.3.x ?

[meistermeier]

Regarding the next release subject you noted, does it mean the current 2.7.18 will then use your next "6.3.19" (I guess ?) you plan to release on friday ? And this "6.3.19" will be the last version you will release for the 6.3.x versions ? Or am I mistaken ?

Unfortunately no, the release in November was the last open source release. I also just learned this the past week.

Another question regarding this issue you fixed. Was it also present on the 7.x.x versions ? Or did you fix exclusively for the 6.3.x ?

No worries, I fixed it in the current versions: 7.0.x (which is also EOL), 7.1.x and 7.2.x before I created the backport for 6.3.x for you to have a simple way to verify the behaviour.

[Marc-AntoineGL]

So, if I wanna keep using 2.7 with your correction, until my spring upgrades, I will need to keep your 6.3.14-GH-2819-SNAPSHOT in my pom.xml file ?