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https://issues.apache.org/jira/browse/SPARK-47863?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vladimir Golubev updated SPARK-47863:
-------------------------------------
Description:
*CollationSupport.EndsWIth* and *CollationSupport.StartsWith* use
{*}CollationAwareUTF8String.matchAt{*}, which operates byte offsets to compare
prefixes/suffixes. This is not correct, since sometimes string parts
(suffix/prefix) of different lengths are actually equal in context of
case-insensitive and lower-case collations.
Example test cases that highlight the problem:
{{{}- *assertContains("The İo", "i̇o", "UNICODE_CI", true);* for
*CollationSupportSuite.*{}}}{{{}{*}testContains{*}.{}}}
{{{}- *assertEndsWith("The İo", "i̇o", "UNICODE_CI", true);* for
*CollationSupportSuite.*{}}}{{{}{*}testEndsWith{*}.{}}}
{{The first passes, since it uses *StringSearch* directly, the second one does
not.}}
was:
*CollationSupport.EndsWIth* and *CollationSupport.StartsWith* use
{*}CollationAwareUTF8String.matchAt{*}, which operates byte offsets to compare
prefixes/suffixes. This is not correct, since sometimes string parts
(suffix/prefix) of different lengths are actually equal in context of
case-insensitive and lower-case collations.
Example test cases that highlight the problem:
{{{}- *assertContains("The İo", "i̇o", "UNICODE_CI", true);* for
*CollationSupportSuite.*{}}}{{{}{*}testContains{*}.{}}}
{{{}- *assertEndsWith("The İo", "i̇o", "UNICODE_CI", true);* for
}}{*}{{CollationSupportSuite.{*}{}}}{{{}{*}testEndsWith{*}.{}}}
{{The first passes, since it uses *StringSearch* directly, the second one does
not.}}
> endsWith and startsWith don't work correctly for some collations
> ----------------------------------------------------------------
>
> Key: SPARK-47863
> URL: https://issues.apache.org/jira/browse/SPARK-47863
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 4.0.0
> Reporter: Vladimir Golubev
> Priority: Major
>
> *CollationSupport.EndsWIth* and *CollationSupport.StartsWith* use
> {*}CollationAwareUTF8String.matchAt{*}, which operates byte offsets to
> compare prefixes/suffixes. This is not correct, since sometimes string parts
> (suffix/prefix) of different lengths are actually equal in context of
> case-insensitive and lower-case collations.
> Example test cases that highlight the problem:
> {{{}- *assertContains("The İo", "i̇o", "UNICODE_CI", true);* for
> *CollationSupportSuite.*{}}}{{{}{*}testContains{*}.{}}}
> {{{}- *assertEndsWith("The İo", "i̇o", "UNICODE_CI", true);* for
> *CollationSupportSuite.*{}}}{{{}{*}testEndsWith{*}.{}}}
> {{The first passes, since it uses *StringSearch* directly, the second one
> does not.}}
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