feat(devframe): async generator RPC functions#312
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Add `type: 'generator'` for `defineRpcFunction` so handlers declared as `async function*` stream their yields to the caller without manual channel scaffolding. The framework substitutes the user's definition with an internal action wrapper that allocates a sink on a hidden `devframe:rpc:generators` channel and returns a stream-id envelope; the client wrapper unwraps the envelope and `streaming.subscribe()`s automatically, so `await rpc.call(name, args)` resolves to a ready-to-iterate `StreamReader<Y>`. Cancellation flows through `getCurrentRpcStream()` — an AsyncLocalStorage helper that mirrors `getCurrentRpcSession()` and exposes the sink's `signal`, `streamId`, and originating session inside the handler body. Server-side callers can iterate without paying for the streaming round-trip via `invokeLocalGenerator(rpc, name, ...args)`. Per-stream `replayWindow` defaults to 256 (floored to 1) to win the client-subscribe-vs-first-yield race; this required threading the existing `RpcStreamingChannel.start()` helper to accept a per-stream override on top of the channel default. Generator definitions reject `agent`, `cacheable`, `dump`, `snapshot`, and `jsonSerializable: true` at registration via four new diagnostics (DF0033–DF0036). DF0034 fires at runtime if the handler doesn't return an `AsyncIterable`. Also fixes a pre-existing replay bug in `node/rpc-streaming.ts`: when a producer closed with an error and a subscriber arrived during the `closedStreamRetention` window, the late subscriber received a clean close instead of the original error. The streaming record now captures the end payload and replays it on subscribe. Migrations & dogfooding: - Streaming guide gains an "Async Generator RPC" section ahead of the manual channel section, framed as the recommended path. - `devframe-streaming-chat` example adds a `:tokenize` generator alongside the existing `:send` action so readers can compare both approaches in one place. - `skills/devframe` and `skills/vite-devtools-kit` get matching guidance. - 12 new integration tests (`rpc-generators.test.ts`) covering happy path, cooperative cancel, throw mid-stream, throw before first yield, late-subscriber replay, concurrent isolation, `invokeLocalGenerator`, and all four validation diagnostics. tsnapi snapshots updated for the new public exports (`getCurrentRpcStream`, `invokeLocalGenerator`, `attachRpcGenerators`, `RpcGeneratorStreamContext`, `RpcGeneratorFunctionDefinition`). Pre-PR checklist (lint + 462 tests + typecheck + build) all green. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Description
Adds
type: 'generator'todefineRpcFunctionso handlers declared asasync function*stream their yields to the client without manual channel scaffolding. The framework substitutes the user's definition with an internal action wrapper that allocates a sink on a hiddendevframe:rpc:generatorschannel and returns an envelope; the client wrapper unwraps it andstreaming.subscribe()s automatically, soawait rpc.call(...)resolves to a ready-to-iterateStreamReader<Y>. Cancellation flows throughgetCurrentRpcStream()— an AsyncLocalStorage helper that mirrorsgetCurrentRpcSession()— andinvokeLocalGenerator(rpc, name, ...args)lets server-side callers iterate without paying for the streaming round-trip. Generator definitions rejectagent,cacheable,dump,snapshot, andjsonSerializable: trueat registration via four new diagnostics (DF0033–DF0036). Also fixes a pre-existing replay bug innode/rpc-streaming.ts: when a producer closed with an error and a subscriber arrived during theclosedStreamRetentionwindow, the late subscriber received a clean close instead of the original error — the streaming record now captures and replays the end payload.Linked Issues
Follow-up to #307. Builds the higher-level ergonomic surface that the streaming-channel API was designed to enable.
Additional context
rpc-generators.test.tsadds 12 integration tests covering happy path, cooperative cancel viagetCurrentRpcStream().signal, throw mid-stream, throw before first yield, late-subscriber replay, concurrent isolation,invokeLocalGenerator, and all four validation diagnostics.skills/devframeandskills/vite-devtools-kitget matching guidance.devframe-streaming-chatexample adds a:tokenizegenerator alongside the existing:sendaction so readers can compare both approaches.replayWindowdefaults to 256 (floored to 1) to win the client-subscribe-vs-first-yield race; this required threadingRpcStreamingChannel.start()to accept a per-stream override on top of the channel default.agentexposure for generators, bidirectional generators, generator return values.🤖 Generated with Claude Code