ia-php-laravel

Modern PHP 8.4 and Laravel patterns: architecture, Eloquent, migrations, queues, testing. Use when working with Laravel, Eloquent, Blade, artisan, or building/testing a framework-based PHP app. Not for php-src internals, standalone PHP libraries, or general PHP language discussion.

PHP & Laravel Development

Code Style

• declare(strict_types=1) in every file
• Happy path last -- guards and errors first, success at the end. Early returns, no else.
• Comments explain why, never what. Never comment tests. If code needs a "what" comment, rename or restructure.
• No single-letter variables -- $exception not $e, $request not $r
• ?string not string|null. Always specify void. Import classnames, never inline FQN.
• Validation uses array notation ['required', 'email'] for easier custom rule classes
• PHPStan level 8+ (phpstan analyse --level=8); aim for 9 on new projects. @phpstan-type / @phpstan-param for generic collection types.

Modern PHP (8.4)

Use when applicable -- no explanatory comments for these in generated code:

• Readonly classes/properties for immutable data; constructor promotion with readonly
• Enums with methods and interfaces for domain constants
• Match expressions over switch
• First-class callable syntax $fn = $obj->method(...)
• Fibers for cooperative async when Swoole/ReactPHP not available
• DNF types (Stringable&Countable)|null for complex constraints
• Property hooks: public string $name { get => strtoupper($this->name); set => trim($value); }
• Asymmetric visibility: public private(set) string $name -- public read, private write
• new without parentheses in chains: new MyService()->handle()
• array_find(), array_any(), array_all() -- native array search/check without closures wrapping Collection

Laravel Architecture

• Escalate structure only when it pays for itself. Simple CRUD → a fat Eloquent model + Form Request is correct; do not add layers. Reach for an Action class when an operation crosses model boundaries or gains a 3rd caller. Extract a non-Eloquent domain object only when a business rule needs testing without booting the DB, or protects an invariant the model can't. Default down the ladder, not up -- an unused abstraction is a defect, not foresight.
• Thin controllers -- only validate, call service/action, return response. Domain behavior (scopes, accessors, relationships) lives in models; cross-cutting orchestration in service classes.
• Service classes for business logic with readonly DI: __construct(private readonly PaymentService $payments)
• Action classes (single-purpose invokable) for operations crossing service boundaries
• Form Requests for all validation -- never inline in controllers, never inside services. Add toDto() so services receive typed, pre-validated data; internal code trusts that input was validated at the boundary.
• Conditional validation: Rule::requiredIf(), sometimes, exclude_if
• Events + Listeners for side effects (notifications, logging, cache invalidation) -- not in services. Name events past-tense in business terms (OrderPlaced, not OrderRecordUpdated). Carry IDs and changed facts in the payload, not the full Eloquent model -- SerializesModels re-fetches by key when a queued listener runs, so a model passed in-memory goes stale (same desync class as the observer/stale-copy pitfall below).
• Feature folder organization over type-based past ~20 models

Production Resilience

• Fail-fast config validation in a service provider's boot(): missing API keys, invalid DSNs, misconfigured queues crash on startup, not on the first request that hits the code path.
• Health endpoints: /health (shallow, 200 if the process responds) and /ready (deep -- checks DB, Redis, critical services).

Routing

• Scoped route model binding to prevent cross-tenant access: Route::scopeBindings()->group(fn() => ...)
• Route::model('conversation', AiConversation::class) for custom binding resolution
• API resource routes: Route::apiResource('posts', PostController::class) -- index/store/show/update/destroy without create/edit

Migrations

• Anonymous class migrations; snake_case plural table names matching model convention
• Foreign keys: $table->foreignId('user_id')->constrained()->cascadeOnDelete(). Always index foreign keys and frequently filtered columns.
• Down method: rollback logic or Schema::dropIfExists() for new tables
• Separate schema and data migrations -- backfills in their own migration file, not mixed with DDL
• Renames/removals use expand-contract: add new column → backfill → switch reads → drop old (full pattern in ia-postgresql skill)
• Never edit a migration that has run in a shared environment -- write a new one
• Set public $withinTransaction = false; for per-row commit/lock-release (resumable backfills) or statements Postgres rejects inside a transaction (CREATE INDEX CONCURRENTLY, ALTER TYPE ... ADD VALUE). Otherwise inner DB::transaction() loops become savepoints, not independent commits (pitfalls-deep.md); no-op on MySQL.
• migrate:fresh resets only the SQL connection -- external stores (DynamoDB, S3, Redis) persist across it, so external-store data migrations re-run on already-migrated data and must be idempotent on a second run.

Eloquent

• Model::preventLazyLoading(!app()->isProduction()) -- catch N+1 during development
• Select only needed columns: Post::with(['user:id,name'])->select(['id', 'title', 'user_id'])
• Bulk operations at database level: Post::where('status', 'draft')->update([...]) -- never load into memory to update. increment()/decrement() for counters.
• Composite indexes for common query combinations
• chunk(1000) for large datasets, lazy collections for memory-constrained processing
• Query scopes (scopeActive, scopeRecent) for reusable constraints
• withCount('comments') / withExists('approvals') -- never load relations just to count
• ->when($filter, fn($q) => $q->where(...)) for conditional query building
• DB::transaction(fn() => ...) -- automatic rollback on exception
• Model::upsert($rows, ['unique_key'], ['update_cols']) for bulk insert-or-update
• Prunable / MassPrunable with prunable() query for automatic stale record cleanup
• $guarded = [] is a mass assignment vulnerability -- always explicit $fillable

API Resources

• whenLoaded() for relationships -- prevents N+1 in responses
• when() / mergeWhen() for permission-based fields; whenPivotLoaded() for pivot data
• withResponse() for custom headers, with() for metadata (version, pagination)

API Design

• Contract-first: define the API Resource (response contract) and Form Request (input contract) before writing the controller.
• Never return raw models or toArray() from controllers -- Resources control exactly what's serialized. Every observable field, ordering, or timing becomes a caller dependency (Hyrum's Law).
• Add, don't modify: new fields/endpoints over changing or removing existing ones. Deprecate first (@deprecated in OpenAPI/docblock), remove in a later version.
• Consistent envelope: { "success": bool, "data": ..., "error": null, "meta": {} }. Normalize ValidationException, ModelNotFoundException, AuthorizationException, and application errors to { "success": false, "error": { "code": "...", "message": "..." } } in the exception handler -- callers build error handling once.
• Isolate third-party SDKs behind an adapter class. Catch vendor exceptions (GuzzleHttp\Exception\ClientException, Stripe\Exception\*) inside the adapter and rethrow as domain exceptions (PaymentFailedException) -- never let a Guzzle/Stripe exception bubble into a controller or service.
• Never return the raw vendor object (Stripe\Charge, a Guzzle Response) from an adapter -- map it to a DTO first. Otherwise every vendor field becomes a caller dependency (Hyrum's Law), same as returning raw models on egress.
• Third-party responses are untrusted data: validate shape and content through the DTO before use in logic or rendering. Inject the specific client/credentials the adapter needs, not the whole config or container.

Queues & Jobs

• Batching: Bus::batch([...])->then()->catch()->finally()->dispatch(); chaining: Bus::chain([new Step1, new Step2])->dispatch()
• Rate limiting: Redis::throttle('api')->allow(10)->every(60)->then(fn() => ...)
• ShouldBeUnique interface to prevent duplicate processing
• Always handle failures -- implement failed() on jobs

Testing (PHPUnit)

Diagnosing failing tests

1. Run the single failing test in isolation (phpunit --filter test_name) before reading app code.
2. Passes solo but fails in the suite → suspect shared state: container singletons, statics, Carbon::setTestNow() residue, DB state leaking between tests (the classic paratest failure).
3. Diff expected vs actual output before hypothesizing a cause.
4. Decide explicitly: test-bug or code-bug. Name which before editing either.
5. Never weaken an assertion to make it pass.

Test throws MissingAttributeException → strict mode (Model::shouldBeStrict()) + factory omits a column with a DB default: add the column to the factory or ->refresh() after create.

Patterns

• Feature tests (tests/Feature/): HTTP through the full stack (getJson(), postJson()) -- default for anything touching routes, controllers, or models. Unit tests (tests/Unit/): isolated services, actions, value objects.
• RefreshDatabase for full migration reset per test; DatabaseTransactions for transaction-wrap (faster, no migration testing); DatabaseMigrations to run and rollback per test
• Model factories for all test data -- never raw DB::table() inserts
• One behavior per test. Name with test_ prefix: test_user_can_update_own_profile
• Assert both response status AND side effects (DB state, jobs, notifications): assertDatabaseHas / assertDatabaseMissing
• actingAs($user) for auth, Sanctum::actingAs($user, ['ability']) for API auth
• Fake facades BEFORE the action: Queue::fake() → act → Queue::assertPushed(...); same for Http::fake(['host/*' => Http::response(...)]) → Http::assertSent(...)
• Gate::forUser($user)->allows('update', $post) for authorization assertions
• Coverage target: 80%+ with pcov or XDEBUG_MODE=coverage in CI

Generic test discipline (anti-patterns, mock rules, rationalization resistance): ia-writing-tests skill. Laravel testing deep dives: see References below.

Common Pitfalls

Real production footguns, invisible to PHPStan and feature tests alone. Extended mechanics and alternatives in pitfalls-deep.md.

Query-builder update() silently skips observers and audit events. Model::query()->where(...)->update([...]) and Relation::update() fire no model events -- observers, Auditable traits, static::saving/updating all bypassed. Fix: lockForUpdate() + save() in a transaction keeps events firing; raw mass update only with a // intentionally bypasses <Observer> comment.

Observer deleting() cleanup at parent scope nukes siblings. Storage::deleteDirectory($parent->uploadPath) on a single child delete wipes storage for all siblings while their rows still point at the keys. Detection: when a single-row delete() has an Observer, check whether its hooks operate at parent or row scope. Fix: scope cleanup to the row's own paths, or move it to an Action that knows the sibling count.

chunkById + json_decode + mutate + json_encode + update loses concurrent writes on jsonb columns. Any user save between the SELECT and the per-row UPDATE is silently overwritten. Fix: in-place DB::raw("jsonb_set(...)") for shallow edits, or lockForUpdate() inside the chunk; the decode/encode default is only safe with writes blocked.

date:<fmt> cast format only reaches $model->toArray(), NOT JsonResource::resolve(). A resource returning the raw attribute emits Carbon's ISO 8601, ignoring the cast -- so a cast-format change is not a wire-format change unless the path uses toArray() directly (Filament, DTOs, json_encode($model)). Verify with a live reproducer before flagging.

Nested-array validation accepts scalar elements when only *.field rules are set. 'items.*.name' => 'string' does not enforce that each items.* is an array -- scalars pass, then $data['items'][0]['name'] yields null (blank row) or a TypeError (500). Always pair per-key rules with 'items.*' => 'array'.

DB::afterCommit prevents run-on-rollback but does NOT retry post-commit failures. Default fix: dispatch a queued job with tries + failed() that reverts the DB precondition. Alternatives in pitfalls-deep.md.

Observer writes a model the caller also holds → stale in-memory copy; the caller's later save() silently re-clobbers. Fix: $model->refresh() after the triggering event, or Model::withoutEvents() when the caller owns the column.

BelongsToMany::attach / detach / sync / updateExistingPivot are query-builder writes -- no pivot model events fire. Observers and audit traits record nothing. Fix: make the pivot a real Pivot model (->using(PivotModel::class)) and write through it with firstOrCreate(...)->fill([...])->save().

Carbon::parse('2020') is today at 20:20, not year 2020 -- a bare 4-digit string parses as HHMM time-of-day, breaking before_or_equal:today / after / before on year-only input. Fix: Carbon::createFromFormat('Y', $year)->startOfYear() + partial-date-aware rules; when migrating a field's validator type, audit its sibling validators for the same incompatibility.

Discipline

• Simplicity first -- every change as simple as possible, minimal code impact
• Only touch what's necessary -- no unrelated changes
• No hacky workarounds -- if a fix feels wrong, step back and implement the clean solution
• New abstraction requires 3+ usage sites; otherwise inline it
• No empty catch blocks -- log or rethrow, never swallow
• Verify before declaring done: ./vendor/bin/phpstan analyse --level=8 && ./vendor/bin/phpunit with zero warnings

Production Performance

OPcache + JIT + preloading configuration and Laravel deploy caches (config:cache, route:cache, etc.): production-performance.md

References

• laravel-ecosystem.md -- Notifications, Task Scheduling, Custom Casts
• testing.md -- PHPUnit essentials, data providers, running tests
• feature-testing.md -- Auth, validation, API, console, DB assertions
• mocking-and-faking.md -- Facade fakes, action mocking, Mockery
• factories.md -- States, relationships, sequences, afterCreating hooks
• production-performance.md -- OPcache, JIT, preloading, deploy caches
• pitfalls-deep.md -- afterCommit alternatives, observer-desync mechanics, jsonb race, savepoint mechanics