[jira] [Resolved] (VELTOOLS-182) MathTool.max longtime bug with args (0,0)

["Claude Brisson (Jira)" <de...@velocity.apache.org>]

     [ https://issues.apache.org/jira/browse/VELTOOLS-182?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Claude Brisson resolved VELTOOLS-182.
-------------------------------------
    Fix Version/s: 3.1
         Assignee: Claude Brisson
       Resolution: Fixed

Fixed

> MathTool.max longtime bug with args (0,0)
> -----------------------------------------
>
>                 Key: VELTOOLS-182
>                 URL: https://issues.apache.org/jira/browse/VELTOOLS-182
>             Project: Velocity Tools
>          Issue Type: Bug
>          Components: GenericTools
>    Affects Versions: 2.0
>            Reporter: Sanford Whiteman
>            Assignee: Claude Brisson
>            Priority: Major
>             Fix For: 3.1
>
>
> It appears that {{$math.max}} has had a bug since at least 2.0, or at least I'm at a loss as to why the observed behavior would be expected, and it doesn't appear to be documented.
>  
> {code:java}
> $math.max(0,0) {code}
>  
> returns
>  
> {code:java}
> 4.9E-324{code}
>  
> that is, Double.MIN_VALUE.
>  
> It's easy to see why in the source. Using [3.0|https://apache.googlesource.com/velocity-tools/+/trunk/velocity-tools-generic/src/main/java/org/apache/velocity/tools/generic/MathTool.java#377] here, we see:
>  
> {code:java}
>     public Number max(Object... nums)
>     {
>         double value = Double.MIN_VALUE;
>         Number[] ns = new Number[nums.length];
>         for (int i=0; i<nums.length; i++)
>         {
>             Number n = toNumber(nums[i]);
>             if (n == null)
>             {
>                 return null;
>             }
>             value = Math.max(value, n.doubleValue());
>             ns[i] = n;
>         }
>         return matchType(value, ns);
>     }
> {code}
>  
> So rather than delegating to {{Java.lang.Math.max}} directly, each iter takes the {{Math.max}} of the current value and Double.MIN_VALUE. Ergo, if the arguments are 0, that's always < Double.MIN_VALUE, so the result is in turn Double.MIN_VALUE.
> The same goes for {{$math.max(0)}} (just one arg) but at least that could be considered a usage error.



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