Jeff Davis ea1db8ae70 Canonicalize ICU locale names to language tags. ... Convert to BCP47 language tags before storing in the catalog, except during binary upgrade or when the locale comes from an existing collation or template database. The resulting language tags can vary slightly between ICU versions. For instance, "@colBackwards=yes" is converted to "und-u-kb-true" in older versions of ICU, and to the simpler (but equivalent) "und-u-kb" in newer versions. The process of canonicalizing to a language tag also understands more input locale string formats than ucol_open(). For instance, "fr_CA.UTF-8" is misinterpreted by ucol_open() and the region is ignored; effectively treating it the same as the locale "fr" and opening the wrong collator. Canonicalization properly interprets the language and region, resulting in the language tag "fr-CA", which can then be understood by ucol_open(). This commit fixes a problem in prior versions due to ucol_open() misinterpreting locale strings as described above. For instance, creating an ICU collation with locale "fr_CA.UTF-8" would store that string directly in the catalog, which would later be passed to (and misinterpreted by) ucol_open(). After this commit, the locale string will be canonicalized to language tag "fr-CA" in the catalog, which will be properly understood by ucol_open(). Because this fix affects the resulting collator, we cannot change the locale string stored in the catalog for existing databases or collations; otherwise we'd risk corrupting indexes. Therefore, only canonicalize locales for newly-created (not upgraded) collations/databases. For similar reasons, do not backport. Discussion: https://postgr.es/m/8c7af6820aed94dc7bc259d2aa7f9663518e6137.camel@j-davis.com Reviewed-by: Peter Eisentraut		2023-04-04 10:38:58 -07:00
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src	Canonicalize ICU locale names to language tags.	2023-04-04 10:38:58 -07:00
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