[gr8man]

Description

This PR optimizes DataCaster::castAs() by compiling and caching type cast rules on demand per unique type in DataCaster::$compiledTypes.

Motivation and Context

In DataCaster::castAs(), hydrating model rows and entity attributes repeatedly triggered the following operations for every single field of every hydrated row:

1. preg_match('/\A(.+)\[(.+)\]\z/', $type, $matches) to detect array/parameterized cast definitions (e.g., json[array], datetime[Y-m-d]).
2. explode(',', ...) and array_map(trim(...), ...) to parse parameters.
3. Multiple reflection checks via is_subclass_of($handler, CastInterface::class) and is_subclass_of($handler, EntityCastInterface::class) when $strict === false (the default mode used by Entity casting).

For a query fetching 1,000 rows with 10 fields per row, this resulted in 10,000 regex executions and 20,000 reflection checks.

By caching the compiled [$handler, $params] keyed by $type:

• All fields sharing the same cast type (e.g. int, bool, csv) share the compiled rule across the lifetime of the caster.
• preg_match, explode, trim, and is_subclass_of execute only once per unique cast type.
• $type = $this->types[$field] ?? null provides a single array lookup fast path.
• setTypes(array $types) preserves the compiled cache when called with identical types (as Entity::castAs() does on every field), while safely invalidating $compiledTypes if types are modified dynamically.

Benchmark & Performance Impact

Microbenchmark executing 900,000 castAs() calls with a mix of types (int, bool, float, csv, json[array], ?int):

• Before: ~6,440 ms (7.16 us / call) - ~139,000 casts/s
• After: ~2,943 ms (3.27 us / call) - >305,000 casts/s
• Speedup: 2.18x faster (-54% time)

Backward Compatibility (100% BC)

• DataCaster is a final class with private properties; no public or protected API signatures have changed.
• The order and semantics of null handling and exceptions are strictly preserved:
  • Null value for nullable field (?type) immediately returns null.
  • Null value for non-nullable field in strict mode throws InvalidArgumentException('Field "..." is not nullable, but null was passed.') before checking handler validity.
  • Invalid method throws CastException::forInvalidMethod() upfront.

Checklist

• Code follows the style guidelines of this project
• Tests have been added to cover the changes
• Static analysis (PHPStan) passes without errors
• PHP-CS-Fixer passes without errors

[carson-codeigniter4]

Hi there, @gr8man! 👋

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