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C#

C# static code analysis

Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C# code

  • All rules 493
  • Vulnerability46
  • Bug88
  • Security Hotspot24
  • Code Smell335

  • Quick Fix 61
Filtered: 11 rules found
multi-threading
    Impact
      Clean code attribute
        1. Blocks should not be synchronized on local variables

           Bug
        2. Threads should not lock on objects with weak identity

           Code Smell
        3. "Thread.Resume" and "Thread.Suspend" should not be used

           Bug
        4. "this" should not be exposed from constructors

           Code Smell
        5. "ConfigureAwait(false)" should be used

           Code Smell
        6. "async" methods should not return "void"

           Bug
        7. "ThreadStatic" fields should not be initialized

           Bug
        8. Instance members should not write to "static" fields

           Code Smell
        9. Shared resources should not be used for locking

           Bug
        10. Blocks should be synchronized on read-only fields

           Bug
        11. Locks should be released on all paths

           Bug

        Blocks should be synchronized on read-only fields

        intentionality - complete
        reliability
        Bug
        • cwe
        • multi-threading

        Why is this an issue?

        How can I fix it?

        More Info

        Locking on a class field synchronizes not on the field itself, but on the object assigned to it. Thus, there are some good practices to follow to avoid problems related to thread synchronization.

        • Locking on a non-readonly field makes it possible for the field’s value to change while a thread is in the code block, locked on the old value. This allows another thread to lock on the new value and access the same block concurrently.
          private Color color = new Color("red");
          private void DoSomething()
          {
            // Synchronizing access via "color"
            lock (color) // Noncompliant: lock is actually on object instance "red" referred to by the "color" field
            {
              //...
              color = new Color("green"); // other threads now allowed into this block
              // ...
            }
          }
          
        • Locking on a new instance of an object undermines synchronization because two different threads running the same method in parallel will lock on different instances of the same object, allowing them to access the synchronized block at the same time.
          private void DoSomething()
          {
            lock (new object()) // Noncompliant: every thread locks on a different new instance
            {
              // ...
            }
          }
          
        • Locking on a string literal is also dangerous since, depending on whether the string is interned or not, different threads may or may not synchronize on the same object instance.
          private readonly string colorString = "red";
          private void DoSomething()
          {
            lock (colorString)  // Noncompliant: strings can be interned
            {
              // ...
            }
          }
          
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