[SOLVED] How to Project a path in NEO4J for topological sorting?

How to Project a path in NEO4J for topological sorting?

I am making a package manager using a neo4j database with packages as nodes and DEPENDS_ON relationships. To build package A, I first need to build packages B and C, for example. And to do that I need to do a topological sort, but IDK how to project the paths using gds.graph.project().

Here is how I get the paths that I need to project:

MATCH path = (n:Package{name: 'neofetch'})-[r:DEPENDS_ON*]->(l:Leaf)

I project the above path to a GDS graph using:

RETURN gds.graph.project("g", n, l, {})

and then do topological sort:

CALL gds.dag.topologicalSort.stream("g", {computeMaxDistanceFromSource: true})
YIELD nodeId, maxDistanceFromSource
RETURN gds.util.asNode(nodeId).name AS name, maxDistanceFromSource
ORDER BY maxDistanceFromSource, name

The result is only the first node and last nodes no intermediate nodes appear in the sort.

Solution

You need to pass every adjacent pair of nodes in the path(s), not just the first and last node. This should work for you:

MATCH (:Package{name: 'neofetch'})-[rels:DEPENDS_ON*]->(:Leaf)
UNWIND rels AS r
WITH DISTINCT r
RETURN gds.graph.project("g", STARTNODE(r), ENDNODE(r))