Merge Multiple Files - ThisShouldNotHappenError - neo4jclient c#

Question

Trying to make a Cypher request which should create (or merge) files and create a relationship to a given root Folder (which may doesn't exists yet). There is a uniquness constraint on :FILE(fullpath) and :FOLDER(fullpath). The Code I have written looks like this:

     async public void createFiles(File[] files, Folder rootFolder)
     {
         var query = client.Cypher
             .Merge("(root:FOLDER {fullpath: {newRoot}.fullpath})")
             .Merge("(file:FILE {fullpath : {newFiles}.fullpath})")
             .Set("file = {newFiles}")
             .CreateUnique("root -[:CONTAINS]->(file)")
             .WithParam("newFiles", files)
             .WithParam("newRoot", rootFolder)
             .ReturnDistinct<int>("0");
         await query.ResultsAsync;
      }

But it throws an Neo4jClient.NeoException: ThisShouldNotHappenError: Developer: Andres claims that: Need something with properties exception. I think the Exception is thrown by the second .Merge. Isn't it possible to merge multiple nodes with an array as parameter? Is it a bug or is it my smelling code?

neo4j 2.1.3

Answer 1

fadanner,

Assuming all of the underlying parts are present in the parameters, you can do what you want by changing your query to this:

var query = client.Cypher
    .Merge("(root:FOLDER {fullpath : {newRoot}.fullpath})")
    .ForEach("(newFile IN {newFiles} | MERGE (file:FILE {fullpath : newFile.fullpath}) SET file = newFile CREATE UNIQUE (root)-[:CONTAINS]->(file))")
    .WithParam("newFiles", files)
    .WithParam("newRoot", rootFolder)
    .ReturnDistinct<int>("0");

I'm not a neo4jclient guy, so I may have some part of the syntax wrong, but this equivalent works with REST (at least I think its equivalent).

:POST /db/data/cypher
    {"query":"MERGE (n:Foo {name : {prop1}.name}) FOREACH(prop IN {prop2} | MERGE (m:Goo {name : prop.name}) SET m = prop CREATE UNIQUE (n)-[:HAS]->(m))", "params":{"prop1":{"name":"cat"},"prop2":[{"name":"boo","gleek":"math"},{"name":"oob","gleek":"spit"}]}}

Grace and peace,

Jim