CA2002: Do not lock on objects with weak identity
Note
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| Item | Value |
|---|---|
| TypeName | DoNotLockOnObjectsWithWeakIdentity |
| CheckId | CA2002 |
| Category | Microsoft.Reliability |
| Breaking Change | Non-breaking |
Cause
A thread attempts to acquire a lock on an object that has a weak identity.
Rule Description
An object is said to have a weak identity when it can be directly accessed across application domain boundaries. A thread that tries to acquire a lock on an object that has a weak identity can be blocked by a second thread in a different application domain that has a lock on the same object. The following types have a weak identity and are flagged by the rule:
How to Fix Violations
To fix a violation of this rule, use an object from a type that is not in the list in the Description section.
When to Suppress Warnings
Do not suppress a warning from this rule.
Related Rules
CA2213: Disposable fields should be disposed
Example
The following example shows some object locks that violate the rule.
using System;
using System.IO;
using System.Reflection;
using System.Threading;
namespace ReliabilityLibrary
{
class WeakIdentities
{
void LockOnWeakId1()
{
lock(typeof(WeakIdentities)) {}
}
void LockOnWeakId2()
{
MemoryStream stream = new MemoryStream();
lock(stream) {}
}
void LockOnWeakId3()
{
lock("string") {}
}
void LockOnWeakId4()
{
MemberInfo member = this.GetType().GetMember("LockOnWeakId1")[0];
lock(member) {}
}
void LockOnWeakId5()
{
OutOfMemoryException outOfMemory = new OutOfMemoryException();
lock(outOfMemory) {}
}
}
}
Imports System
Imports System.IO
Imports System.Reflection
Imports System.Threading
Namespace ReliabilityLibrary
Class WeakIdentities
Sub SyncLockOnWeakId1()
SyncLock GetType(WeakIdentities)
End SyncLock
End Sub
Sub SyncLockOnWeakId2()
Dim stream As New MemoryStream()
SyncLock stream
End SyncLock
End Sub
Sub SyncLockOnWeakId3()
SyncLock "string"
End SyncLock
End Sub
Sub SyncLockOnWeakId4()
Dim member As MemberInfo = _
Me.GetType().GetMember("SyncLockOnWeakId1")(0)
SyncLock member
End SyncLock
End Sub
Sub SyncLockOnWeakId5()
Dim outOfMemory As New OutOfMemoryException()
SyncLock outOfMemory
End SyncLock
End Sub
End Class
End Namespace