apoc.refactor.mergeNodes singleElementAsArray config property ignored

Neo4j Graph Platform Procedures & APOC
1

Hi all,

Looking at the documentation for mergeNodes it seems that properties that are merged to create a single element array can be coerced into an atomic value (the default), or kept as a single-element array if the singleElementAsArray config is set to true (see "config properties" table on referenced page).

When attempting to merge nodes in a very simple graph:

merge (:ToMerge {prop1: ['single array'], prop2: 'atom'})
merge (:ToMerge {prop1: ['single array'], prop2: 'alone'})

... using the cypher:

match (n1:ToMerge {prop2: 'atom'})
match (n2:ToMerge {prop2: 'alone'})
with [n1, n2] as nodes
call apoc.refactor.mergeNodes(nodes, {properties: "combine", singleElementAsArray: true}) yield node
return node

A single merged node results (as expected); on this node prop2 is ['atom', 'alone'] (also as expected) but prop1 is 'single array' rather than ['single array'] as I expected (the single element array is converted to an atomic value).

I'm not sure if this is a user error or a documentation issue; any help appreciated.

2

@neo4j11 what apoc version are you using?

3

I've tried it with 4.2.0.0-all, and with a 4.0 version and it appears not to work in either.
4.2 version can be tested using dockerised neo:

docker run -p7474:7474 -p7687:7687 -e NEO4J_AUTH=neo4j/neo4k -e NEO4JLABS_PLUGINS=\[\"apoc\"\] neo4j

then running the cypher from the comment above

4

@neo4j11 the feature is not yet released, the docs are updated automatically by a process but they should not show that feature at this time sorry for the mistake.
I'll talk to the team to plan a new release ASAP but if you want in the meanwhile you can build it from the source.
Thank you so much!
Andrea