Neo4jClient Transaction Error - neo4j

Question

When I try to update an existing Node in Neo4JClient without using transaction, which has a Unique Constraint on Id and Name property, I receive this Exception:
CypherExecutionException: Node 6 already exists with label User and property "Name"=[Mike]
But when I try to update a Node in transaction, I receive this Exception:
Received an unexpected HTTP status when executing the request.
The response status was: 404 Not Found
The response from Neo4j (which might include useful detail!) was: {"results":[],"errors":[{"code":"Neo.ClientError.Transaction.UnknownId","message":"Unrecognized transaction id. Transaction may have timed out and been rolled back."}]}
My Code is like this:
using (var transaction = client.BeginTransaction())
{
client.Cypher
.Merge("(user:User { Id: {id}})")
.OnCreate().Set("user = {user}")
.OnMatch().Set("user = {user}")
.WithParams(new { id = user.Id, user = user })
.ExecuteWithoutResults();
transaction.Commit();
}
My question is: Is there a way to get the actual error when using transaction, like I get one when I don't use transaction?
Thanks
EDIT 1:
It looks like the NULL Id in not being handled correctly. After drilling down, I managed to pull the actual error. The first exception in is:
errors = {[
{
"code": "Neo.ClientError.Statement.InvalidSemantics",
"message": "Cannot merge node using null property value for Id"
}
]}
The stack trace for this exception is:
at Neo4jClient.Serialization.CypherJsonDeserializer1.GetRootResultInTransaction(JObject root) in [PATH_HIIDEN]\Neo4jClient\Serialization\CypherJsonDeserializer.cs:line 316
at Neo4jClient.Serialization.CypherJsonDeserializer1.CheckForErrorsInTransactionResponse(String content) in [PATH_HIIDEN]\Neo4jClient\Serialization\CypherJsonDeserializer.cs:line 291
at Neo4jClient.GraphClient.<>c__DisplayClass84_01.<PrepareCypherRequest>b__0(Task1 responseTask) in [PATH_HIIDEN]\Neo4jClient\GraphClient.cs:line 933
at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
at System.Threading.Tasks.Task.Execute()
And after that there is the exception with 404 NOT Found error. For that the stack trace is:
at Neo4jClient.Execution.HttpResponseMessageExtensions.EnsureExpectedStatusCode(HttpResponseMessage response, String commandDescription, HttpStatusCode[] expectedStatusCodes) in [PATH_HIIDEN]\Neo4jClient\Execution\HttpResponseMessageExtensions.cs:line 41
at Neo4jClient.Execution.HttpResponseMessageExtensions.EnsureExpectedStatusCode(HttpResponseMessage response, HttpStatusCode[] expectedStatusCodes) in [PATH_HIIDEN]\Neo4jClient\Execution\HttpResponseMessageExtensions.cs:line 14
at Neo4jClient.Execution.ResponseBuilder.<>c__DisplayClass21_0.b__0(Task1 requestTask) in [PATH_HIIDEN]\Neo4jClient\Execution\ResponseBuilder.cs:line 127
at System.Threading.Tasks.ContinuationResultTaskFromResultTask2.InnerInvoke()
at System.Threading.Tasks.Task.Execute()
Can this error be fixed in the next release please?
EDIT 2
using (var transaction = client.BeginTransaction())
{
manifest.Users = client.Cypher
.Merge("(n:User { Id: '8be0b8fd-c433-44d3-a7e2-3f0d1a03fefa'}) " +
"ON CREATE " +
"SET n = { " +
"Id: '8be0b8fd-c433-44d3-a7e2-3f0d1a03fefa', " +
"UserName: 'test.user', " +
"Name: 'Test User', " +
"Active: true " +
"} " +
"ON MATCH " +
"SET n = { " +
"Id: '8be0b8fd-c433-44d3-a7e2-3f0d1a03fefa', " +
"UserName: 'test.user', " +
"Name: 'Test User', " +
"Active: true " +
"}")
.Return(n => n.As<User>())
.Results
.ToList();
transaction.Commit();
}
Meaning fluent Api is causing the error.

Answer 1

So the problem is that in Neo4j 2.2.6 a change was introduced whereby any ClientError (Constraint Violation etc) resulted in an automatic Rollback of a transaction on the server.
Neo4jClient already did an auto-rollback on error, and continued to do so. With 2.2.6 this resulted in a 404 error as the transaction was no longer there (previous versions were fine).
So, I've made a fix and published an updated Nuget package, so version 1.1.0.12 of Neo4jClient will now give you the correct response.