Merge pull request #149 from driseley/connection-leak-148

Fix for Connection leak issue

Author: senseibaka

src/AdoNetCore.AseClient/Internal/ConnectionPool.cs

@@ -64,13 +64,28 @@ public IInternalConnection Reserve(IInfoMessageEventNotifier eventNotifier)
                         throw new OperationCanceledException();
                     }
 
-                    connection.ChangeDatabase(_parameters.Database);
-                    connection.SetTextSize(_parameters.TextSize);
-                    connection.NamedParameters = _parameters.NamedParameters;
-
-                    if (_parameters.AnsiNull)
+                    try
+                    {
+                        connection.ChangeDatabase(_parameters.Database);
+                        connection.SetTextSize(_parameters.TextSize);
+                        connection.NamedParameters = _parameters.NamedParameters;
+
+                        if (_parameters.AnsiNull)
+                        {
+                            connection.SetAnsiNull(_parameters.AnsiNull);
+                        }
+                    }
+                    catch (Exception)
                     {
-                        connection.SetAnsiNull(_parameters.AnsiNull);
+                        if(_parameters.Pooling)
+                        {
+                            RemoveConnection(connection);
+                        }
+                        else
+                        {
+                            connection?.Dispose();
+                        }
+                        throw;
                     }
 
                     return connection;

test/AdoNetCore.AseClient.Tests/Unit/ConnectionPoolTests.cs

@@ -46,6 +46,24 @@ public void WhenMinPoolSizeIsSet_NewPoolFillsToMin()
             Assert.AreEqual(10, pool.PoolSize);
         }
 
+        [Test]
+        public void WhenChangeDatabaseThrows_PoolDoesNotLeak()
+        {
+            var parameters = new TestConnectionParameters
+            {
+                MaxPoolSize = 5,
+                LoginTimeout = 1
+            };
+
+            var pool = new ConnectionPool(parameters, new ImmediateConnectionFactory(changeDatabaseThrows: true));
+
+            for (int i=0; i<5; i++)
+            {
+                Assert.Throws<AseException>(() => pool.Reserve(null));
+            }
+            Assert.AreEqual(0, pool.PoolSize);
+        }
+
         [Test]
         public void NewOpenCall_TimesOut_ShouldThrow()
         {
@@ -155,16 +173,27 @@ public void PoolSpam_Blitz(short size, int threads)
 
         private class ImmediateConnectionFactory : IInternalConnectionFactory
         {
+            private readonly bool _changeDatabaseThrows;
+
+            public ImmediateConnectionFactory(bool changeDatabaseThrows = false)
+            {
+                _changeDatabaseThrows = changeDatabaseThrows;
+            }
             public async Task<IInternalConnection> GetNewConnection(CancellationToken token, IInfoMessageEventNotifier eventNotifier)
             {
-                return await Task.FromResult<IInternalConnection>(new DoNothingInternalConnection());
+                return await Task.FromResult<IInternalConnection>(new DoNothingInternalConnection(_changeDatabaseThrows));
             }
         }
 
         [SuppressMessage("ReSharper", "UnassignedGetOnlyAutoProperty")]
         [SuppressMessage("ReSharper", "UnusedMember.Local")]
         private class DoNothingInternalConnection : IInternalConnection
         {
+            private readonly bool _changeDatabaseThrows;
+            public DoNothingInternalConnection(bool changeDatabaseThrows = false)
+            {
+                _changeDatabaseThrows = changeDatabaseThrows;
+            }
             public void Dispose() { }
             public DateTime Created { get; }
             public DateTime LastActive { get; }
@@ -174,7 +203,10 @@ public bool Ping()
                 return true;
             }
 
-            public void ChangeDatabase(string databaseName) { }
+            public void ChangeDatabase(string databaseName)
+            {
+                if (_changeDatabaseThrows) throw new AseException("ChangeDatabase exception");
+            }
             public string Database { get; }
             public string DataSource { get; }
             public string ServerVersion { get; }