Sort filter values in a locale aware way

[boo-code]

Questions	Answers
Description?	Feature filter values were ordered with natcasesort() (in Filters\Block::sortFeatureBlock()), which compares strings byte by byte. Multi-byte accented characters (Czech č, š, ř, …) therefore sorted after every plain ASCII letter instead of next to their base letter, so e.g. Černá landed at the bottom of the list rather than right after Czech. The fix sorts with a Collator built from the current language locale (when the intl extension is available), using a secondary strength (case-insensitive, as natcasesort was) and numeric collation (to keep the natural 2-before-10 ordering). It falls back to natcasesort() when intl is unavailable.
Type?	bug fix
BC breaks?	no
Deprecations?	no
Fixed ticket?	Fixes #1201.
How to test?	A unit test is included (BlockTest::testSortFeatureBlockSortsValuesLocaleAware): with locale cs-CZ, a feature whose values are Value, Else, Beta, Černá, Czech, Other, Alpha is sorted to Alpha, Beta, Czech, Černá, Else, Other, Value (red before / green after). Manually: create a feature with Czech accented values (č, š, ř, …), enable it as a filter, and check the storefront filter block — the values are now alphabetically ordered per the language instead of pushing accented ones to the end.
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Reported by @Hlavtox. Verified that Collator(cs-CZ) reproduces the exact expected order from the issue (Alpha, Beta, Czech, Černá, Else, Other, Value), whereas natcasesort() produces Alpha, Beta, Czech, Else, Other, Value, Černá.

[ps-jarvis]

Hello @boo-code!

This is your first pull request on ps_facetedsearch repository of the PrestaShop project.

Thank you, and welcome to this Open Source community!

[kpodemski]

thanks @boo-code

CI is red.

Details:

 @php -d date.timezone=UTC ./vendor/bin/phpunit -c tests/php/phpunit.xml
PHPUnit 5.7.27 by Sebastian Bergmann and contributors.

.......................................................E.......  63 / 101 ( 62%)
......................................                          101 / 101 (100%)

Time: 226 ms, Memory: 16.00MB

There was 1 error:

1) PrestaShop\Module\FacetedSearch\Tests\Filters\BlockTest::testGetFiltersBlockWithoutFeaturesWithoutSearchFilterAndFeatures
Undefined property: stdClass::$locale

/home/runner/work/ps_facetedsearch/ps_facetedsearch/src/Filters/Block.php:950
/home/runner/work/ps_facetedsearch/ps_facetedsearch/src/Filters/Block.php:909
/home/runner/work/ps_facetedsearch/ps_facetedsearch/src/Filters/Block.php:895
/home/runner/work/ps_facetedsearch/ps_facetedsearch/src/Filters/Block.php:149
/home/runner/work/ps_facetedsearch/ps_facetedsearch/tests/php/FacetedSearch/Filters/BlockTest.php:1043
phpvfscomposer:///home/runner/work/ps_facetedsearch/ps_facetedsearch/vendor/phpunit/phpunit/phpunit:51

ERRORS!
Tests: 101, Assertions: 923, Errors: 1.
Script @php -d date.timezone=UTC ./vendor/bin/phpunit -c tests/php/phpunit.xml handling the test event returned with error code 2

[boo-code]

Thanks for catching that. Fixed in f51ef4d: getValuesCollator() read $this->context->language->locale unconditionally, which raised an Undefined property notice on the fixtures whose language carries no locale. It now guards the access and falls back to natcasesort() when no locale is set. PHPUnit is green again.

[Hlavtox]

Oooooh lalaaa, nice!!!!

[boo-code]

The waiting for author label here is stale: the red CI reported on 2026-07-07 was fixed the same day in f51ef4d (getValuesCollator() now guards the access to $this->context->language->locale and falls back to natcasesort() when no locale is set), and the approval came after that commit. Nothing is pending on my side, and the PR also carries Waiting for QA with all checks green.

[Hlavtox]

@boo-code Audrius, ping us on slack DM every time you need something bumped, so we are not stuck. Me, @Codencode or @kpodemski for example.