Null Reference Exception during INSERT/SELECT

[jchannon]

I have a SQL statement that runs fine with ngpsql v2.2.0 and dapper 1.36 which looks like so

INSERT INTO MyTable (Name,Msg) Values(@Name, @Msg); 
SELECT MAX(Id) FROM MyTable

I am using it like so:

connection.Query<int>(sql,
                     new {
                       item.Name,
                       item.Msg
                     }).First();

However when it runs with ngpsql v3.0.3 or ngpsql v3.1.0-alpha3 I get a NullReferenceException

Exception(Type:NullReferenceException):Object reference not set to an instance of an object
  at Dapper.SqlMapper+<QueryImpl>d__11`1[System.Int32].MoveNext () [0x00000] in <filename unknown>:0
  at System.Collections.Generic.List`1[System.Int32].AddEnumerable (IEnumerable`1 enumerable) [0x00000] in <filename unknown>:0
  at System.Collections.Generic.List`1[System.Int32]..ctor (IEnumerable`1 collection) [0x00000] in <filename unknown>:0
  at System.Linq.Enumerable.ToList[Int32] (IEnumerable`1 source) [0x00000] in <filename unknown>:0
  at Dapper.SqlMapper.Query[Int32] (IDbConnection cnn, System.String sql, System.Object param, IDbTransaction transaction, Boolean buffered, Nullable`1 commandTimeout, Nullable`1 commandType) [0x00000] in <filename unknown>:0

Any ideas?

I've also logged it with ngpsql as I'm unsure where the issue is: npgsql/npgsql#857

[mgravell]

Very odd. The first thing I would say is update to dapper vLatest - best
case it fixes it, worst case I can compare the stack trace to the current
code. Very interesting, and not one I've seen.
On 5 Nov 2015 8:01 am, "Jonathan Channon" notifications@github.com wrote:

I have a SQL statement that runs fine with ngpsql v2.2.0 and dapper 1.36
which looks like so

INSERT INTO MyTable (Name,Msg) Values(@name, @msg);
SELECT MAX(Id) FROM MyTable

I am using it like so:

connection.Query(sql,
new {
item.Name,
item.Msg
}).First();

However when it runs with ngpsql v3.0.3 or ngpsql v3.1.0-alpha3 I get a
NullReferenceException

Exception(Type:NullReferenceException):Object reference not set to an instance of an object
at Dapper.SqlMapper+d__111[System.Int32].MoveNext () [0x00000] in <filename unknown>:0 at System.Collections.Generic.List1[System.Int32].AddEnumerable (IEnumerable1 enumerable) [0x00000] in <filename unknown>:0 at System.Collections.Generic.List1[System.Int32]..ctor (IEnumerable1 collection) [0x00000] in <filename unknown>:0 at System.Linq.Enumerable.ToList[Int32] (IEnumerable1 source) [0x00000] in :0
at Dapper.SqlMapper.Query[Int32](IDbConnection cnn, System.String sql, System.Object param, IDbTransaction transaction, Boolean buffered, Nullable1 commandTimeout, Nullable1 commandType) [0x00000] in :0

Any ideas?

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#383.

[Yantrio]

We seem to be getting this on the latest dapper also, (1.42) with npgsql 3.0.3 :( same stacktrace also.

[jchannon]

FYI @Yantrio and I work together

On Thursday, 5 November 2015, James Humphries notifications@github.com
wrote:

We seem to be getting this on the latest dapper also, (1.42) with npgsql
3.0.3 :( same stacktrace also.

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#383 (comment)
.

[NickCraver]

Hey guys, the latest on NuGet is 1.50 beta1, can you try that and see if you're still seeing the null ref? There were 2 fixes related I folded in recently - it may already be resolved. If not, we'll have a proper stack to investigate against current.

[roji]

@NickCraver, I've confirmed this as an issue with Npgsql, Dapper doesn't seem to be at fault here in any way. See npgsql/npgsql#857 (comment) for an explanation of what is going on.

[jchannon]

Thanks @roji I'll close the issue