JAVA.FUNCS.INFREC : Potential Infinite Recursion (Java)

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CodeSonar^® 9.2p0

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Java

JAVA.FUNCS.INFREC : Potential Infinite Recursion (Java)

Summary

A method call looks infinitely recursive.

This checker identifies very simple cases of infinite recusion, when a method calls itself with exactly the same parameter values. This leads very often to an infinite recursion and is likely to be a programming bug. Note, however, that, in reality, there might not be an actual infinite recursion if the state is modified by the method and termination depends on those changes of state. Although, in those cases, it could still be argued that the programmer is using a bad, unclear programming pattern and should at least clarify the code.

Properties

Class Name

Potential Infinite Recursion (Java)

Significance

reliability

Mnemonic

JAVA.FUNCS.INFREC

Example

public class Loop {
  public static void main(String[] args) {
      System.out.println(new Loop().pow(args.length));
  }

  public int pow(int i) {
      int j = i;
      if (i == 0)
          return 1;
      else
          return 2 * pow(j); // "Potential Infinite Recursion (Java)" warning issued here
  }
}

The programmer probably forgot a -1 in the parameter of the recursive call. To resolve the issue, they should correct the recursive call in order to guarantee a decreasing chain of recursive parameter values.

  public int pow(int i) {
      int j = i;
      if (i == 0)
          return 1;
      else
          return 2 * pow(j - 1);
}

Resolution

Check if there is an actual possibility of non-termination and correct the recursion accordingly.

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.

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