[release/6.0] SQLite: Don't modify collection while enumerating inside ReclaimLeakedConnections

src/Microsoft.Data.Sqlite.Core/SqliteConnectionPool.cs

@@ -5,6 +5,7 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Linq;
 using System.Threading;
 
 namespace Microsoft.Data.Sqlite
@@ -157,17 +158,17 @@ private bool ReclaimLeakedConnections()
  {
  var leakedConnectionsFound = false;
 
+ List<SqliteConnectionInternal> leakedConnections;
  lock (_connections)
  {
- foreach (var connection in _connections)
- {
- if (connection.Leaked)
- {
- Return(connection);
+ leakedConnections = _connections.Where(c => c.Leaked).ToList();
+ }
 
- leakedConnectionsFound = true;
- }
- }
+ foreach (var connection in leakedConnections)
+ {
+ leakedConnectionsFound = true;
+
+ Return(connection);
  }
 
  return leakedConnectionsFound;

test/Microsoft.Data.Sqlite.Tests/SqliteConnectionFactoryTest.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Data;
 using System.IO;
+using System.Runtime.CompilerServices;
 using SQLitePCL;
 using Xunit;
 
@@ -218,6 +219,26 @@ public void EnableExtensions_doesnt_bleed_across_connections()
  Assert.Equal(disabledMessage, ex.Message);
  }
 
+ [Fact]
+ public void Clear_works_when_connection_leaked()
+ {
+ using var connection = new SqliteConnection(ConnectionString);
+ connection.Open();
+
+ LeakConnection();
+ GC.Collect();
+
+ SqliteConnection.ClearPool(connection);
+
+ [MethodImpl(MethodImplOptions.NoInlining)]
+ static void LeakConnection()
+ {
+ // Don't add using!
+ var connection = new SqliteConnection(ConnectionString);
+ connection.Open();
+ }
+ }
+
  public void Dispose()
  {
  SqliteConnection.ClearAllPools();