1+ // Licensed to the .NET Foundation under one or more agreements.
2+ // The .NET Foundation licenses this file to you under the MIT license.
3+ // See the LICENSE file in the project root for more information.
4+
5+ using System ;
6+ using System . Data ;
7+ using System . Reflection ;
8+ using System . Threading . Tasks ;
9+ using Xunit ;
10+
11+ namespace Microsoft . Data . SqlClient . UnitTests . Microsoft . Data . SqlClient
12+ {
13+ /// <summary>
14+ /// Regression tests for GitHub issue #3314.
15+ ///
16+ /// Root cause: TryOpenInner() read InnerConnection twice - once for TryOpenConnection() and
17+ /// again for the cast to SqlConnectionInternal. Between those two reads another thread could
18+ /// change _innerConnection to DbConnectionClosedConnecting, which is not assignable to
19+ /// SqlConnectionInternal, causing an opaque InvalidCastException.
20+ ///
21+ /// Fix: InnerConnection is now captured into a local variable once; if it is not a
22+ /// SqlConnectionInternal an InvalidOperationException with a descriptive message is thrown
23+ /// instead of an InvalidCastException.
24+ /// </summary>
25+ public class SqlConnectionConcurrentOpenTests
26+ {
27+ private static object GetConnectingSingleton ( )
28+ {
29+ Type closedConnectingType = typeof ( SqlConnection ) . Assembly
30+ . GetType ( "Microsoft.Data.ProviderBase.DbConnectionClosedConnecting" , throwOnError : true ) ! ;
31+ FieldInfo singletonField = closedConnectingType
32+ . GetField ( "SingletonInstance" , BindingFlags . Static | BindingFlags . NonPublic | BindingFlags . Public ) ! ;
33+ object ? singletonInstance = singletonField . GetValue ( null ) ;
34+ Assert . NotNull ( singletonInstance ) ;
35+ return singletonInstance ! ;
36+ }
37+
38+ private static void ForceInnerConnection ( SqlConnection connection , object innerConnectionValue )
39+ {
40+ FieldInfo innerConnectionField = typeof ( SqlConnection )
41+ . GetField ( "_innerConnection" , BindingFlags . Instance | BindingFlags . NonPublic ) ! ;
42+ innerConnectionField . SetValue ( connection , innerConnectionValue ) ;
43+ }
44+
45+ [ Fact ]
46+ public void InnerConnection_DbConnectionClosedConnecting_IsNotAssignableToSqlConnectionInternal ( )
47+ {
48+ object connectingSingleton = GetConnectingSingleton ( ) ;
49+
50+ Type sqlConnectionInternalType = typeof ( SqlConnection ) . Assembly
51+ . GetType ( "Microsoft.Data.SqlClient.Connection.SqlConnectionInternal" , throwOnError : true ) ! ;
52+
53+ Assert . False (
54+ sqlConnectionInternalType . IsInstanceOfType ( connectingSingleton ) ,
55+ "DbConnectionClosedConnecting must NOT be assignable to SqlConnectionInternal. " +
56+ "If it were, the race condition in #3314 would not manifest." ) ;
57+ }
58+
59+ [ Fact ]
60+ public void InnerConnection_InConnectingState_ReportsConnectingState ( )
61+ {
62+ object connectingSingleton = GetConnectingSingleton ( ) ;
63+
64+ var connection = new SqlConnection ( "Data Source=localhost" ) ;
65+ ForceInnerConnection ( connection , connectingSingleton ) ;
66+
67+ Assert . Equal ( ConnectionState . Connecting , connection . State ) ;
68+ }
69+
70+ [ Fact ]
71+ public void Open_WhenAlreadyConnecting_ThrowsInvalidOperation ( )
72+ {
73+ object connectingSingleton = GetConnectingSingleton ( ) ;
74+
75+ var connection = new SqlConnection ( "Data Source=localhost" ) ;
76+ ForceInnerConnection ( connection , connectingSingleton ) ;
77+
78+ Assert . Throws < InvalidOperationException > ( ( ) => connection . Open ( ) ) ;
79+ }
80+
81+ [ Fact ]
82+ public void TryOpenInner_WhenInnerConnectionRacesToConnectingState_ThrowsInvalidOperation_NotInvalidCast ( )
83+ {
84+ object connectingSingleton = GetConnectingSingleton ( ) ;
85+
86+ Type openBusyType = typeof ( SqlConnection ) . Assembly
87+ . GetType ( "Microsoft.Data.ProviderBase.DbConnectionOpenBusy" , throwOnError : true ) ! ;
88+ FieldInfo openBusySingleton = openBusyType
89+ . GetField ( "SingletonInstance" , BindingFlags . Static | BindingFlags . NonPublic | BindingFlags . Public ) ! ;
90+ object ? openBusyInstance = openBusySingleton . GetValue ( null ) ;
91+ Assert . NotNull ( openBusyInstance ) ;
92+
93+ var connection = new SqlConnection ( "Data Source=localhost" ) ;
94+ ForceInnerConnection ( connection , connectingSingleton ) ;
95+
96+ Type dbConnectionInternalType = typeof ( SqlConnection ) . Assembly
97+ . GetType ( "Microsoft.Data.ProviderBase.DbConnectionInternal" , throwOnError : true ) ! ;
98+ Type tcsType = typeof ( TaskCompletionSource < > ) . MakeGenericType ( dbConnectionInternalType ) ;
99+ object completedRetry = Activator . CreateInstance ( tcsType ) ! ;
100+ MethodInfo setResultMethod = tcsType . GetMethod ( "SetResult" ) ! ;
101+ setResultMethod . Invoke ( completedRetry , new [ ] { openBusyInstance ! } ) ;
102+
103+ MethodInfo tryOpenInner = typeof ( SqlConnection )
104+ . GetMethod ( "TryOpenInner" , BindingFlags . Instance | BindingFlags . NonPublic ) ! ;
105+ Assert . NotNull ( tryOpenInner ) ;
106+
107+ Exception ex = Assert . ThrowsAny < Exception > ( ( ) =>
108+ {
109+ try
110+ {
111+ tryOpenInner . Invoke ( connection , new [ ] { completedRetry } ) ;
112+ }
113+ catch ( TargetInvocationException tie ) when ( tie . InnerException != null )
114+ {
115+ throw tie . InnerException ;
116+ }
117+ } ) ;
118+
119+ Assert . True (
120+ ex is InvalidOperationException ,
121+ $ "Expected InvalidOperationException but got { ex . GetType ( ) . Name } : { ex . Message } . "+
122+ "The fix for #3314 must throw InvalidOperationException (not InvalidCastException) " +
123+ "when _innerConnection races to a non-SqlConnectionInternal state inside TryOpenInner." ) ;
124+
125+ Assert . Contains ( "connection" , ex . Message , StringComparison . OrdinalIgnoreCase ) ;
126+ }
127+ }
128+ }
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