NET-2626 New Rule Idea: Synchronization objects should be released in a finally block #9769
Description
Description
Synchronization types like Semaphore[Slim], Mutex etc. should be used with try/finally after acquiring the lock, with the release operation happening in the finally block. If an exception occurs in the guarded section, the release operation is never called, leaving the object locked for longer than necessary, potentially even forever (deadlock). The finally block guarantees that the lock is always released.
Noncompliant code snippet
private readonly SemaphoreSlim _semaphore;
// ------
await _semaphore.WaitAsync();
// The synchronized code
_semaphore.Release();Compliant code snippet
private readonly SemaphoreSlim _semaphore;
// ------
await _semaphore.WaitAsync();
try
{
// The synchronized code
}
finally
{
_semaphore.Release();
}