Programming

Programming

Language-specific patterns and tooling for Go, Kotlin, PHP, Swift, and TypeScript. Identify the language, load matching deep references, follow the language section.

Language Routing

If the request spans multiple languages, apply each relevant section.

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Go

Style Precedence

1. Target repository's explicit rules and compatibility constraints.
2. Google Go Style Guide canonical rules.
3. Google Go Style Decisions normative guidance.
4. Google Go Style Best Practices non-canonical recommendations.
5. Task-specific deep references below.

Prefer local consistency only where the Google guide allows judgment. Do not restyle existing code without cause.

Workflow

1. Classify the task: testing, concurrency, error handling, code review, SAPCC conventions, or quality gate.
2. Load the matching deep reference.
3. Follow the reference's phases, gates, and completion criteria.

For testing: table-driven tests with subtests, test helpers, mock injection. Run go test ./.... Load references/go/testing.md. For concurrency: goroutine lifecycle, sync primitives, context propagation, race detection. Run go test -race. Load references/go/concurrency.md. For error handling: wrapping with %w, sentinel errors, errors.Is/errors.As, custom error types. Load references/go/error-handling.md. For code review: review checklist, common comments, interface compliance. Load references/go/code-review.md. For SAPCC repos: org conventions -- go-bits patterns, auth ordering, JSON strictness, endpoint identification. Load references/go/sapcc-conventions.md. For quality gate: run make check or equivalent. Load references/go/quality-gate.md.

Expert Review Patterns

Beyond linting -- patterns from real code reviews that automated tools miss:

• Type export design: keep implementation types unexported; export only interfaces and constructors.
• Batch+callback races: commit() should remove only the specific batch returned, not all items.
• Function extraction: extract only if reused elsewhere or hides complex details.
• Defer timing: place defer f.Close() after the error check, not before.
• Go 1.22+ loop variables: remove i := i reassignment and closure parameter passing -- each iteration has its own variable since 1.22.
• Prometheus metrics: pre-initialize counters with .Add(0) for all known label combinations.
• Test dedup: use testWithEachBackingStore() pattern to share test bodies across interface implementations.

Scripts

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Kotlin

Core Rules

1. Structured concurrency is non-negotiable. Every coroutine must have a parent scope that defines its lifetime.
2. Inject dispatchers. Accept CoroutineDispatcher as a parameter so callers and tests control threading.
3. Always rethrow CancellationException. Catch specific exception types, not broad Exception.
4. Prefer Flow over Channel. Flow is cold, composable, handles backpressure. Use Channels only for producer-consumer and inter-coroutine communication.
5. Use supervisorScope for partial failure tolerance. Independent tasks that should not cancel each other.
6. No GlobalScope. Pass a scope from the application framework.

Stream Type Selection

Flow: cold -- each collector gets its own execution. Chain with filter, map, flatMapConcat. Terminate with collect. StateFlow: requires initial value, always replays latest to new collectors. Use for UI state. SharedFlow: configurable replay, emits all values (no conflation). Use for event streams. Channel: hot communication primitive. Use produce builder for producer-consumer. Fan-out: multiple coroutines consuming one channel. Fan-in: multiple producers writing to one channel.

Workflow

1. Classify into concurrency, Flow, Channels, or testing.
2. Load matching deep reference.
3. Apply patterns from the reference as templates.

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PHP

Core Rules

• Every PHP file must begin with declare(strict_types=1).
• Follow PSR-12: 4-space indentation, no trailing whitespace, one class per file, visibility on all members, opening braces same line for control structures, next line for classes and methods.

Framework Idioms

Laravel: Eloquent scopes for reusable query constraints (scopeActive). Collection methods over raw loops (collect()->filter()->map()->sort()). Service Container for interface-to-implementation binding. Contextual binding with when()->needs()->give().

Symfony: DI with #[Autowire] attributes for constructor injection. #[AsEventListener] for event dispatch. Rely on autowiring over XML config.

Workflow

1. Assess. Classify: code review, type system, framework patterns, tooling setup, or test writing. Load matching deep reference.
2. Execute. For quality reviews: check strict_types, PSR-12, modern features, framework idioms, tooling. For testing: PHPUnit TestCase with test prefix, @dataProvider for table-driven, createStub() for returns, createMock() for interactions, parent::setUp() first in every setUp.
3. Verify. Run ./vendor/bin/phpunit. For coverage: XDEBUG_MODE=coverage ./vendor/bin/phpunit --coverage-text --coverage-min=80.

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