Warning CA2200: Rethrow to preserve stack details

.NET code analyzer rule CA2200 is enabled, by default, starting in .NET 5.0. It produces a build warning for any catch blocks that rethrow an exception and the exception is explicitly specified in the throw statement.

Change description

Starting in .NET 5, the .NET SDK includes .NET source code analyzers. Several of these rules are enabled, by default, including CA2200. If your project contains code that violates this rule and is configured to treat warnings as errors, this change could break your build.

Rule CA2200 flags code where exceptions are rethrown and the exception variable is specified in the throw statement. When an exception is thrown, part of the information it carries is the stack trace. The stack trace is a list of the method call hierarchy that starts with the method that throws the exception and ends with the method that catches the exception. If an exception is rethrown by specifying the exception in the throw statement, the stack trace restarts at the current method and the list of method calls between the original method that threw the exception and the current method is lost. To keep the original stack trace information with the exception, use the throw statement without specifying the exception.

The following code snippet does not produce a warning for rule CA2200. The commented line would trigger a violation, however.

catch (ArithmeticException e)
{
    // throw e;
    throw;
}

Version introduced

5.0

  • Rethrow exceptions without specifying the exception explicitly. For more information, see CA2200.

  • To disable code analysis completely, set EnableNETAnalyzers to false in your project file. For more information, see EnableNETAnalyzers.

Affected APIs

Not detectable via API analysis.