Merge upstream sabre-io/vobject 5.0.0

[willaix]

What

Syncs our fork with upstream sabre-io/vobject 5.0.0 (2026-07-07). This is a breaking release:

• PHP 8.2+ is required (PHP 7.4, 8.0 and 8.1 are dropped)
• Parameter and return types are declared across the codebase, so callers must pass the correct types
• The test toolchain moves to PHPUnit 11, PHPStan strict rules and Rector

Our previous sync (#116) linked our history to upstream's, so git only had to compare changes since 4.6.0. The merge had 5 conflicts.

Commits

1. a6e164cf Merge upstream 5.0.0. Conflict resolution only:
   • RRuleIterator: keeps our yearlySkipUpperLimit constructor parameter, the fast-forward helpers and the [day, hour, minute, second] occurrences, on top of upstream's promoted $startDate, strict comparisons and
     $selectedOccurrence. The occurrence comparison moves into isOccurrenceAfter().
   • RRuleIteratorTest: keeps our version where it conflicted (see follow-ups).
   • TimeZoneUtilTest: keeps our tests and the Europe/Kyiv filter, in upstream's PHPUnit 11 form.
   • Version.php stays at 4.35.0. The bump comes in the release PR.
2. 32c942b3, 3473176c are cherry-picks of upstream chore: apply rector IfToNullCoalescingAssignRector rule sabre-io/vobject#787, made after 5.0.0. Upstream 5.0.0 fails the current Rector check, and chore: apply rector IfToNullCoalescingAssignRector rule sabre-io/vobject#787 is upstream's fix for it.
3. 3b084ae5 Adapt Proton code to 5.x tooling. No behaviour change intended:
   • Tests: static data providers, DataProvider attributes, self::assert*
   • RRuleIterator: readonly promoted $yearlySkipUpperLimit, match for the frequency coefficient, integer tuple comparison when sorting occurrences, and ruleValuesOrCurrent() instead of short ternaries
   • GuessFromCustomizedTimeZone: explicit checks on getTransitions(), which returns array|false

To see exactly how each conflict was resolved:

  git show --remerge-diff a6e164cf

Testing

Run locally on PHP 8.4, the same checks as CI:

• vendor/bin/phpunit --configuration tests/phpunit.xml: 3282 tests pass, 1 skipped
• composer phpstan: no errors
• vendor/bin/rector process --dry-run: no changes
• php-cs-fixer: no changes

PHPUnit reports 56 deprecations (metadata in doc comments). 53 of them are in upstream's own tests at 5.0.0, which upstream has since fixed (sabre-io#788). They only become errors with PHPUnit 12.

Follow-ups (not in this PR)

• Summer-time handling for monthly/yearly recurrences. Upstream's monthly and yearly DST-transition tests fail against our iterator. It sets the time from the occurrence directly, which skips upstream's summer-time fix. This has
  been the case since 4.31 and this PR doesn't change it. It will get its own PR, together with bringing back upstream's DST tests adapted to our parse() test helper.
• Upstream master after 5.0.0: a CI action bump, failOnDeprecation, and a PHP 8.5 deprecation fix in VCard. These come with the next sync.

Merging and release

• ⚠️ Merge with "Create a merge commit". Do not squash, so upstream's history stays part of ours.
• A follow-up PR release/5.0.0 will bump the version and add a changelog entry calling out the breaking changes.
• Consumers: projects using this package must run PHP 8.2+ before moving to ^5.0. Until then they stay on ^4.35.