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https://issues.apache.org/jira/browse/VELOCITY-996?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Claude Brisson closed VELOCITY-996.
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> Precision loss when Long values are converted to BigDecimal in VTL arithmetic
> -----------------------------------------------------------------------------
>
> Key: VELOCITY-996
> URL: https://issues.apache.org/jira/browse/VELOCITY-996
> Project: Velocity
> Issue Type: Bug
> Components: Engine
> Affects Versions: 2.4.1
> Reporter: Kai Bächle
> Assignee: Claude Brisson
> Priority: Minor
> Fix For: 2.5
>
>
> MathUtils.toBigDecimal(Number) appears to convert Number instances through
> doubleValue() before creating a BigDecimal.
> This loses precision for large integral values such as Long.MAX_VALUE. As a
> result, VTL arithmetic and comparisons involving a Long and a BigDecimal can
> produce unexpected results.
> Minimal VTL example, without any Java context:
>
> {code:java}
> ## Pure VTL test for MathUtils.toBigDecimal(Long) precision issue
> #set($L = 9223372036854775807) ## Long.MAX_VALUE => Long
> #set($BI = 9223372036854775808) ## one above Long.MAX_VALUE => BigInteger
> ## Create BigDecimal values without Java context:
> #set($BD0 = ($BI + 0.0) - $BI) ## BigDecimal 0.0
> #set($BDL = $BI - 1.0) ## BigDecimal 9223372036854775807.0
> Long literal (L): $L ($L.class.simpleName)
> BigInteger literal (BI): $BI ($BI.class.simpleName)
> BigDecimal zero (BD0): $BD0 ($BD0.class.simpleName)
> BigDecimal Long.MAX (BDL): $BDL ($BDL.class.simpleName)
> -- OK: pure integer arithmetic --
> #set($a = $L + 0)
> L + 0 = $a ($a.class.simpleName)
> #set($b = $L + 1)
> L + 1 = $b ($b.class.simpleName)
> -- Double path, precision loss is expected here --
> #set($c = $L + 0.0)
> L + 0.0 = $c ($c.class.simpleName)
> -- BigDecimal path, unexpected precision loss --
> #set($d = $L + $BD0)
> L + BigDecimal(0.0) = $d ($d.class.name)
> -- Comparison against exact BigDecimal Long.MAX_VALUE --
> L == BigDecimal(Long.MAX) = #if($L == $BDL)true#{else}false#end
> L > BigDecimal(Long.MAX) = #if($L > $BDL)true#{else}false#end{code}
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