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https://issues.apache.org/jira/browse/MNG-8240?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Elliotte Rusty Harold closed MNG-8240.
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> ComparableVersion incorrectly handles leading Unicode Nd class zeros
> --------------------------------------------------------------------
>
> Key: MNG-8240
> URL: https://issues.apache.org/jira/browse/MNG-8240
> Project: Maven
> Issue Type: Bug
> Environment: openjdk version "1.8.0_412"
> OpenJDK Runtime Environment (Temurin)(build 1.8.0_412-b08)
> OpenJDK 64-Bit Server VM (Temurin)(build 25.412-b08, mixed mode)
> Reporter: Matthew Donoughe
> Assignee: Elliotte Rusty Harold
> Priority: Major
>
> ComparableVersion supports positive decimal numbers of unlimited size. As an
> optimization, the size of the number (in UCS-2 codepoints) determines whether
> the value should be converted into an int or a long or a BigDecimal. As
> another optimization, because the size of the value affects the data type, an
> int is always smaller than a long which is always smaller than a BigDecimal.
> Leading 0s are removed to avoid the case where 00000000000000000001 > 2.
> However, it's specifically '0', DIGIT ZERO, 0x0030, that is being removed.
> The code that segments the version string into items uses
> [Character.isDigit|https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/Character.html#isDigit(char)],
> which uses
> [Character.getType|https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/Character.html#getType(char)]
> to check for
> [DECIMAL_DIGIT_NUMBER|https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/Character.html#DECIMAL_DIGIT_NUMBER]
> corresponding to the [Unicode Nd
> class|https://www.fileformat.info/info/unicode/category/Nd/list.htm], and
> parsing into a number eventually uses
> [Character.digit|https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/Character.html#digit(char,int)]
> which likewise supports Unicode Nd class digits. This leads to the following
> case:
> {noformat}
> java -jar
> ~/.m2/repository/org/apache/maven/maven-artifact/3.9.4/maven-artifact-3.9.4.jar
> ०००००००००००००००००००1 0000000000000000000000002
> Display parameters as parsed by Maven (in canonical form and as a list of
> tokens) and comparison result:
> 1. ०००००००००००००००००००1 -> 1; tokens: [1]
> ०००००००००००००००००००1 > 0000000000000000000000002
> 2. 0000000000000000000000002 -> 2; tokens: [2]{noformat}
> A 1 with 19 leading zeros is parsed as a BigDecimal, and a 2 with 24 leading
> zeros is parsed as an int, so therefore 1 > 2. However, the canonicalization
> still works correctly, so if you canonicalize the versions before comparing
> them you get 1 < 2 as expected. I don't know if that's better or worse
> because it can lead to the order being unstable.
> I guess the easy solution is to use Character.digit to check for int 0
> instead of char '0'.
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