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https://issues.apache.org/jira/browse/VELTOOLS-182?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16854935#comment-16854935
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Sanford Whiteman commented on VELTOOLS-182:
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Yes, it's quite bad!
Why not delegate entirely to Java instead? This method is to avoid running a
sort proper against the collection, since it only needs a single return value,
right? Which I understand for large collections, but does this represent
real-world use? (I don't know, I personally never try to get the max of 2-3
user/system/default environment variables.)
> 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
> Priority: Major
>
> 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.min(0)}} (just one arg) but at least that could be
> considered a usage error.
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