Fix hook_entity_operation cacheability parameter should not be nullable

[mglaman]

Summary

• Fixes CacheableMetadata parameter in entity operation hooks is not nullable #984: $cacheability in hook_entity_operation and hook_entity_operation_alter is not nullable — only EntityListBuilder methods use nullable for BC (removed in D12)
• Changed isValidParam(..., true, ...) → false in both hook rules so non-nullable CacheableMetadata $cacheability is accepted (nullable is also still accepted)
• Updated error messages to recommend \Drupal\Core\Cache\CacheableMetadata $cacheability without ? / = NULL
• Added non-nullable "good" fixture examples; kept nullable variants to confirm both pass

Test plan

• php vendor/bin/phpunit --filter=HookEntityOperationCacheabilityRuleTest
• php vendor/bin/phpunit --filter=ProceduralHookEntityOperationCacheabilityRuleTest
• php vendor/bin/phpunit --filter=EntityListBuilderOperationsCacheabilityRuleTest (unchanged, still nullable)
• php vendor/bin/phpcs src/

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Updates the hook entity operation cacheability rules to accept the canonical non-nullable CacheableMetadata $cacheability parameter (while keeping nullable forms accepted) and aligns test fixtures/error messages with that recommendation.

Changes:

• Adjusted both procedural and attribute-based hook rules to accept non-nullable CacheableMetadata parameters.
• Updated rule error messages to recommend the non-nullable canonical signature.
• Expanded test fixtures to include “good” non-nullable examples and updated PHPUnit expectations accordingly.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Rules/Drupal/ProceduralHookEntityOperationCacheabilityRule.php	Accepts non-nullable CacheableMetadata parameter for procedural hook signatures and updates guidance message.
src/Rules/Drupal/HookEntityOperationCacheabilityRule.php	Accepts non-nullable CacheableMetadata parameter for #[Hook(...)] methods and updates guidance message.
tests/src/Rules/ProceduralHookEntityOperationCacheabilityRuleTest.php	Updates expected error messages to recommend non-nullable signature.
tests/src/Rules/HookEntityOperationCacheabilityRuleTest.php	Updates expected error messages to recommend non-nullable signature.
tests/src/Rules/data/mymodule.module	Adds “good” examples for procedural hooks (but currently not actually validated as hooks by the procedural rule).
tests/src/Rules/data/hook-entity-operation-cacheability.php	Adds “good” non-nullable and nullable OOP hook implementations for fixture coverage.