[Intl] Add format_list filter using PHP 8.5's IntlListFormatter

[BreyndotEchse]

Adds a new format_list Twig filter to IntlExtension that formats arrays using using PHP 8.5's IntlListFormatter

On PHP < 8.5, using the filter throws a RuntimeError explaining the dependency on IntlListFormatter (Checks if class_exists to allow polyfills).

CI workflow only covered up to PHP 8.4, so I extended it to also run PHPUnit against 8.5.
phpstan's PHP version also bumped to 8.5.

[fabpot]

It looks good to me.

Can you add a new doc/filters/format_list.rst file (see doc/filters/format_number.rst for an example), update doc/filters/index.rst to add format_list to the list and in extra/intl-extra/README.md?

Also, can you add an entry in CHANGELOG.md?

[BreyndotEchse]

• rebased on latest 3.x
• added docs
• added CHANGELOG

[fabpot]

Thank you @BreyndotEchse.

[upsun-dispatch]

📋 PR Summary

This PR adds a format_list Twig filter to the IntlExtension that formats an array of strings into a locale-aware list using PHP 8.5's IntlListFormatter. On PHP < 8.5 the filter throws a RuntimeError (guarded by class_exists, allowing polyfills), and the CI matrix plus phpstan are bumped to include PHP 8.5. Documentation, README, CHANGELOG, and two test fixtures (pre-8.5 exception path and 8.5 formatting path) are added.

Changes

Layer / File(s)	Summary
filter implementation
extra/intl-extra/IntlExtension.php	Adds formatList public filter method, createListFormatter with LRU-style caching, and lazy availableListTypes/availableListWidths helpers mapping string names to IntlListFormatter constants. Registers the format_list filter.
ci
.github/workflows/ci.yml	Adds PHP 8.5 to the test matrices and bumps the phpstan job's PHP version from 8.4 to 8.5.
docs
doc/filters/format_list.rst	New reference page documenting the filter, its type/width/locale arguments, and examples.
doc/filters/index.rst	Adds format_list to the filters index.
extra/intl-extra/README.md	Lists the new format_list filter with a link.
CHANGELOG	Adds a 3.29.0 entry for the new filter.
tests
extra/intl-extra/Tests/Fixtures/format_list.test	Fixture asserting the RuntimeError is thrown on PHP < 8.5.
extra/intl-extra/Tests/Fixtures/format_list_php85.test	Fixture asserting formatted output across type/width/locale combinations on PHP >= 8.5.

[upsun-dispatch]

📋 Upsun Dispatch Review: full · 8 files reviewed · 🔵 2 infos

Review details

Commit: Commit 163f1b6
Model: claude-opus-4-8
Panel: correctness · robustness · design

[upsun-dispatch]

🔵 Info — Docblock may overpromise Stringable support the formatter does not accept.

The @param array<string|\Stringable> annotation on formatList advertises that \Stringable objects may be passed, but $strings is handed directly to \IntlListFormatter::format(). If the underlying formatter does not coerce \Stringable elements to strings, passing objects (which the annotation permits) raises a TypeError rather than formatting them. The test fixtures only cover plain strings, so this path is unverified.

[upsun-dispatch]

🔵 Info — Undocumented lazy pattern invites a refactor that breaks the extension on PHP < 8.5.

availableListTypes()/availableListWidths() reference the PHP 8.5-only constants \IntlListFormatter::TYPE_AND/WIDTH_WIDE etc., and are intentionally lazy methods (evaluated only after the class_exists guard in formatList) rather than const arrays like the sibling TIME_FORMATS/NUMBER_STYLES. Nothing documents that intent, so a maintainer harmonizing them into class constants would move constant evaluation to class-load time and break loading on PHP < 8.5.