Our website uses cookies to enhance your browsing experience.
Accept
to the top
close form

Fill out the form in 2 simple steps below:

Your contact information:

Step 1
Congratulations! This is your promo code!

Desired license type:

Step 2
Team license
Enterprise license
** By clicking this button you agree to our Privacy Policy statement
close form
Request our prices
New License
License Renewal
--Select currency--
USD
EUR
* By clicking this button you agree to our Privacy Policy statement

close form
Free PVS‑Studio license for Microsoft MVP specialists
* By clicking this button you agree to our Privacy Policy statement

close form
To get the licence for your open-source project, please fill out this form
* By clicking this button you agree to our Privacy Policy statement

close form
I am interested to try it on the platforms:
* By clicking this button you agree to our Privacy Policy statement

close form
check circle
Message submitted.

Your message has been sent. We will email you at


If you haven't received our response, please do the following:
check your Spam/Junk folder and click the "Not Spam" button for our message.
This way, you won't miss messages from our team in the future.

>
>
>
V3080. Possible null dereference.
menu mobile close menu
Analyzer diagnostics
General Analysis (C++)
General Analysis (C#)
General Analysis (Java)
Micro-Optimizations (C++)
Diagnosis of 64-bit errors (Viva64, C++)
Customer specific requests (C++)
MISRA errors
AUTOSAR errors
OWASP errors (C#)
Problems related to code analyzer
Additional information
toggle menu Contents

V3080. Possible null dereference.

Mar 29 2016

The analyzer detected a code fragment that may cause a null-dereference issue.

Consider the following examples, which trigger the V3080 diagnostic message:

if (obj != null || obj.Func()) { ... }
if (obj == null && obj.Func()) { ... }
if (list == null && list[3].Func()) { ... }

All the conditions contain a logical mistake that results in null dereference. This mistake appears as the result of bad code refactoring or a typo.

The following are the fixed versions of the samples above:

if (obj == null || obj.Func()) { .... }
if (obj != null && obj.Func()) { .... }
if (list != null && list[3].Func()) { .... }

These are very simple situations, of course. In real-life code, an object may be tested for null and used in different lines. If you see the V3080 warning, examine the code above the line that triggered it and try to find out why the reference is null.

Here's an example where an object is checked and used in different lines:

if (player == null) {
  ....
  var identity = CreateNewIdentity(player.DisplayName);
  ....
}

The analyzer will warn you about the issue in the line inside the 'if' block. There is either an incorrect condition or some other variable should have been used instead of 'player'.

Sometimes programmers forget that when testing two objects for null, one of them may appear null and the other non-null. It will result in evaluating the entire condition, and null dereference. For example:

if ((text == null && newText == null) || text.Equals(newText)) {
  ....
}

This condition can be rewritten in the following way:

if ((text == null && newText == null) ||
    (text != null && newText != null && text.Equals(newText))) {
  ....
}

Another way to make this mistake is to use the logical AND operator (&) instead of conditional AND (&&). One must remember that, firstly, both parts of the expression are always evaluated when using logical AND, and, secondly, the priority of logical AND is higher than that of conditional AND.

For example:

public static bool HasCookies {
  get {
    var context = HttpContext;
    return context != null
      && context.Request != null & context.Request.Cookies != null
      && context.Response != null && context.Response.Cookies != null;
  }
}

In this code, 'context.Request.Cookies' will be referenced even if 'context.Request' is null.

Dereferencing a parameter that has a default value of 'null' is also dangerous. Here is an example:

public NamedBucket(string name, List<object> items = null)
{
  _name = name;
 
  foreach (var item in items)
  {
    ....
  }
}

The constructor takes the 'items' collection as an optional parameter. However, if the value for 'items' is not passed while calling the constructor, 'NullReferenceException' will be thrown when trying to traverse the collection in 'foreach'. 

The issue may be resolved differently depending on the situation. For example, we can traverse a collection only if it is not equal to 'null'.

This diagnostic is classified as:

You can look at examples of errors detected by the V3080 diagnostic.