rspec/rules/S1696/csharp/rule.adoc

== Why is this an issue?

``++NullReferenceException++`` should be avoided, not caught. Any situation in which ``++NullReferenceException++`` is explicitly caught can easily be converted to a ``++null++`` test, and any behavior being carried out in the catch block can easily be moved to the "is null" branch of the conditional.

=== Noncompliant code example

[source,csharp]
----
public int GetLengthPlusTwo(string str) 
{
    int length = 2;
    try 
    {
       length += str.Length;
    }
    catch (NullReferenceException e) 
    {
        log.info("argument was null");
    }
    return length;
}
----

=== Compliant solution

[source,csharp]
----
public int GetLengthPlusTwo(string str) 
{
    int length = 2;

    if (str != null) 
    {
        length += str.Length;
    }
    else 
    {
        log.info("argument was null");
    }
    return length;
}
----

== Resources

* https://cwe.mitre.org/data/definitions/395[MITRE, CWE-395] - Use of NullPointerException Catch to Detect NULL Pointer Dereference

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