Cannot map path using SDN 6.0.3

[sureshpw]

Similar to issue: #2119. But using apoc.path.expand to get all the paths.
Given a sample model: https://neo4j.com/labs/apoc/4.1/graph-querying/expand-paths/

MATCH (p:Person {name: "Alicia"})
CALL apoc.path.expand(p, "FOLLOWS>|KNOWS", ">Engineering", 1, 3)
YIELD path
RETURN path

Previously this can be mapped using a custom @Query returning a Person node (Spring Boot 2.3.4). That in turn will contain all the relationships and connected nodes. With Spring Boot 2.4.2 and SDN 6.0.3 it is not working.

[meistermeier]

Neo4j-OGM that was used in SDN version < 6 collected all the returned data and mapped it in a batch afterwards.
With targeting real immutability and reactive support in SDN 6, this cannot be done anymore but needs a more record-oriented.
As you have seen at the other issue(s) we currently improving the path mapping but you need also to take action and return a list of path by collecting all resulting parts (collect(path)).
You could include the vmware snapshot repositories

    <repository>
      <id>spring-snapshots</id>
      <name>Spring Snapshots</name>
      <url>https://repo.spring.io/snapshot</url>
      <snapshots>
        <enabled>true</enabled>
      </snapshots>
    </repository>

and try the 6.0.4-SNAPSHOT with the updated query. Would be helpful to get any feedback from your side if this would work or more improvements are needed. Our situation is that we cannot foresee all the ways users create paths. Our improvement unifies paths but there could also be some data inside the path objects that might lead to problems and we are eager to fix those for you.

[sureshpw]

Thanks for the suggestion. Snapshot works fine on one-to-many relationships. But not fetching one-to-one relationships

@Node("A")
class A {
    @Relationship("TO_B")
    B b;

    @Relationship("TO_C")
    Set<C> cset;
}

In this case collect(path) correctly obtains all the elements of cset. But not the TO_B relationship.

[mrksph]

Wow, just found this. It really broke our expand functionality. Thanks for the collect tip

[meistermeier]

@sureshpw could you provide the query you are using to retrieve A, B and C?

@mrksph That is all due to the record-focused mapping as described in #2128 (comment)
This was done intentionally because this is the only way that allows us to not brake a (possible) reactive flow.

[sureshpw]

Not only the one-to-one relationships, collect(path) not returning the grand children (depth > 1) either. Here is a sample project reproducing these problems:

https://github.com/sureshpw/neo4j-path-issue

[mrksph]

@meistermeier Hi Gerrit, if I use "collect(path)" when expanding a node that has many first level relationships (14k+) I can't LIMIT the results because they are one big row.

How'd you do it?

[meistermeier]

@sureshpw There were a problem with the snapshot repository. It did not pick up the latest changes. I re-published the current 6.0.4-SNAPSHOT and from what I see with your test project, everything seems to work. I even migrated the Child and GrandChild relationships from Set to a scalar one and the result stayed the same.

>>>From APOC Path>>>Neo4jApplication.Person(id=20, name=person-1, location=Neo4jApplication.Location(id=23, address=123 Main Street), children=Neo4jApplication.Child(id=21, name=child-1, grandChildren=Neo4jApplication.GrandChild(id=22, name=gchild-1)))

[sureshpw]

@meistermeier I ran the tests again and seeing the correct results. But when I add a one-to-one relationship for the grand-child, that relationship is not being returned. Updated the project. Please check. Thanks.

@meistermeier Updated the model ran the tests again and everything works correctly. When is the ETA for releasing SDN 6.0.4 with this fix? Thanks.

[meistermeier]

I do not have any official at hand (the calendar is down) but since the next milestone of the next released is scheduled for Feb.,17th (https://github.com/spring-projects/spring-data-commons/wiki/Release-Train-2021.0-(Pascal)) I assume that also the next service release of 2020.0 will happen that day.