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patterns.md

Section Inventory

Section Core Python Py# TypeScript TS# .NET DN# Go Go#
Signals ✓ ✓ 1 ✓ 1 ✓ 1 ✓ 1
Dynamic Signal Handlers — ✓ 2 ✓ 2 ✓ 2 — —
Queries ✓ ✓ 3 ✓ 3 ✓ 3 ✓ 2
Dynamic Query Handlers — ✓ 4 ✓ 4 ✓ 4 — —
Updates ✓ ✓ 5 ✓ 5 ✓ 5 ✓ 3
Child Workflows ✓ ✓ 6 ✓ 6 ✓ 6 ✓ 4
Child Workflow Options — — — ✓ 7 — — ✓ 4s
Handles to External Workflows — ✓ 7 ✓ 8 ✓ 7 ✓ 5
Parallel Execution ✓ ✓ 8 ✓ 9 ✓ 8 ✓ 6
Deterministic Asyncio Alternatives — ✓ 9 — — — — — —
Deterministic Task Alternatives — — — — — ✓ 9 — —
Selector Pattern — — — — — — — ✓ 7
Continue-as-New ✓ ✓ 10 ✓ 10 ✓ 10 ✓ 8
Cancellation Handling (asyncio) — ✓ 12 — — — — — —
Cancellation Scopes — — — ✓ 12 — — — —
Cancellation Handling (CancellationToken) — — — — — ✓ 12 — —
Cancellation Handling — — — — — — — ✓ 9
Saga Pattern ✓ ✓ 11 ✓ 11 ✓ 11 ✓ 10
Triggers — — — ✓ 13 — — — —
Wait Condition with Timeout — ✓ 13 ✓ 14 ✓ 13 ✓ 11
Waiting for All Handlers to Finish — ✓ 14 ✓ 15 ✓ 14 ✓ 12
Activity Heartbeat Details ✓ ✓ 15 ✓ 16 ✓ 15 ✓ 13
Timers ✓ ✓ 16 ✓ 17 ✓ 16 ✓ 14
Large Data Handling ✓ — — — — — — — —
Local Activities ✓ ✓ 17 ✓ 18 ✓ 17 ✓ 15
Entity Workflow Pattern ✓ — — — — — — — —
Polling Patterns ✓ — — — — — — — —
Idempotency Patterns ✓ — — — — — — — —
Using Pydantic Models — ✓ 18 — — — — — —

Style Compliance

Language Status Notes
Python ✓ reference —
TypeScript ✓ aligned Uses log, CancellationScope idiom
.NET ✓ aligned Attribute-based handlers, CancellationToken, Workflow.WhenAllAsync/WhenAnyAsync, lambda activity invocations
Go ✓ aligned Channel-based signals, SetQueryHandler, SetUpdateHandler, Selector, compensation slice saga

Status

Cross-language notes:

  • Updates — Validator constraints: All languages (core, Python, TS, Go) now document that validators must NOT mutate state or block (read-only, like query handlers). Added in PR #38 review.
  • Cancellation Handling reordered before Saga in Go (Go# 9→10) so NewDisconnectedContext is introduced before Saga uses it
  • Saga Pattern in Go now uses NewDisconnectedContext for compensations (PR #38 review)
  • Local Activities: added WFT persistence risk warning to core (applies to all languages, not Go-specific). PR #38 review.

Go-specific notes:

  • Child Workflow Options: demoted to ### subsection under Child Workflows in Go (Go# 4s = subsection of 4). TS has it as separate ##.
  • Activity Heartbeating renamed to Activity Heartbeat Details (matching Python/TS naming)

Go-specific notes (API details):

  • Signals use workflow.GetSignalChannel + workflow.Selector (channel-based, not handler-based)
  • Dynamic Signal/Query Handlers: Go handles signals by channel name; no "default handler" concept → marked —
  • Queries use workflow.SetQueryHandler (string name + function)
  • Updates use workflow.SetUpdateHandlerWithOptions with optional Validator
  • Parallel Execution uses workflow.Go() (not goroutines) + workflow.Selector
  • Selector Pattern: Go-specific section — workflow.Selector replaces select statement (unique to Go SDK)
  • Cancellation Handling: Go uses ctx.Done() channel + workflow.NewDisconnectedContext (different from Python asyncio.CancelledError and TS CancellationScope)
  • Saga Pattern: Go idiom uses defer for compensations
  • Wait Condition: Go uses workflow.Await / workflow.AwaitWithTimeout
  • Continue-as-New: Go returns workflow.NewContinueAsNewError (error-based, not function call)
  • Cancellation Scopes / Triggers / Deterministic Asyncio: Not applicable to Go → marked —

.NET-specific notes:

  • Signals/Queries/Updates use [WorkflowSignal], [WorkflowQuery], [WorkflowUpdate] attributes
  • Dynamic handlers use (Dynamic = true) attribute param with IRawValue[] args
  • Cancellation uses standard CancellationToken + TemporalException.IsCanceledException(e) pattern with detached token for cleanup
  • Deterministic Task Alternatives: .NET-specific section covering Workflow.WhenAllAsync, WhenAnyAsync, RunTaskAsync, DelayAsync, Mutex, Semaphore
  • Parallel Execution uses Workflow.WhenAllAsync (not Task.WhenAll)
  • Saga uses List<Func<Task>> for compensations (idiomatic C#)

Decided to keep as Core-only:

  • Large Data Handling: Core conceptual explanation sufficient (language-agnostic pattern)
  • Polling Patterns: Core conceptual explanation sufficient
  • Idempotency Patterns: Core conceptual explanation sufficient

Intentionally missing (—):

  • Dynamic handlers, External workflow handles, Wait conditions: language-specific implementation, core has concepts only
  • Child Workflow Options: TS-specific (Python shows inline)
  • Deterministic Asyncio Alternatives: Python-specific (TS doesn't have this issue)
  • Cancellation Handling vs Cancellation Scopes: different idioms per language
  • Triggers: TS-specific pattern
  • Entity Workflow Pattern: conceptual in core, implementation left to user
  • Using Pydantic Models: Python-specific

Order alignment: ✓ Aligned — TS# and Go# monotonically increase

Style alignment: ✅ All issues fixed (Python, TypeScript, Go, .NET)

  • ✅ Queries: TS now has "Important: must NOT modify state" note
  • ✅ Updates: All languages now have "validators must NOT mutate state or block" note
  • ✅ Saga Pattern: TS now has idempotency note, comments about saving compensation BEFORE activity
  • ✅ Saga Pattern: TS now uses log from @temporalio/workflow