Attachment 113055 Details for Bug 248040 – Different test cases showing where the problem happens and where it doesn't.

Different test cases showing where the problem happens and where it doesn't.

PotentialNullPointerAccess.java (text/plain), 3.17 KB, created by Rodolfo Federico Gamarra

on 2008-09-20 01:08:39 EDT

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Creator: Rodolfo Federico Gamarra

Created: 2008-09-20 01:08:39 EDT

Size: 3.17 KB

patch

obsolete

>package org.eclipse.test;
>public class PotentialNullPointerAccess {
>    public static String notNull() {
>        return "a";
>    }
>    public static boolean doNothing(boolean b){
>    	return false;
>    }
>    /*
>     * Different test cases for Potential Null Pointer Access.
>     */
>    public static void caseA() {
>        String a = notNull();
>        boolean isNotNull = a != null;
>        if(isNotNull) {
>            /*
>             * Wrong: Fake potential null pointer access warning.
>             * Potential null pointer access: The variable a may be null at this location
>             * 
>             * Despite we're checking to be different from null, we get the warning.
>             */
>            a.toString(); 
>        }
>    }
>    public static void caseB() {
>        String a = notNull();
>        if(a != null) {
>            /*
>             * 0k: No potential null pointer access warning.
>             */
>            a.toString(); 
>        }
>    }
>    public static void caseC() {
>        String a = notNull();
>        /*
>         * 0k: No potential null pointer access warning, the analyzer can't 
>         * guess what the outcome would be from the function.
>         */
>        a.toString(); 
>    }            
>    public static void caseD() {    
>        String a = notNull();
>        // We know for sure it won't be null.
>        boolean isNotNull = true;
>        if(isNotNull) {
>            /*
>             * 0k: No potential null pointer access warning.
>             */
>            a.toString(); 
>        }
>    }
>    public static void caseE() {
>        String a = notNull();
>        if(doNothing(a != null)) {
>            /*
>             * Wrong: Fake potential null pointer access warning.
>             * The use of a != null is wrapped inside a function call, the
>             * outcome can be anything.
>             */
>            a.toString(); 
>        }
>    }
>    public static void caseF() {
>        String a = notNull();
>        doNothing(a != null);
>		if(true) {
>            /*
>             * Wrong: Fake potential null pointer access warning.
>             * Note that the call with a != null as parameter is unrelated to the condition.
>             */
>            a.toString(); 
>        }
>    }
>    public static void caseG() {
>        String a = notNull();
>        doNothing(false);
>		if(true) {
>            /*
>             * 0k: No potential null pointer access warning.
>             */
>            a.toString(); 
>        }
>    }
>    public static void caseH() {
>        String a = notNull();
>		if(true) {
>            /*
>             * 0k: No potential null pointer access warning.
>             * Taking into account caseF one could expect this case to give
>             * the warning as well. In both cases the call, with the comparison
>             * as parameter is unrelated to the if block.
>             */
>            a.toString(); 
>        }
>		doNothing(a != null);
>    }
>    public static void caseI() {
>        String a = "a";
>        doNothing(a != null);
>		if(true) {
>            /*
>             * 0k: No potential null pointer access warning.
>             * Despite the check, as a is clearly not null, no warning
>             * is issued.
>             */
>            a.toString(); 
>        }
>    }    
>}

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Attachments on bug 248040: 113055