opencode/packages/codemode/src/interpreter/promises.ts

336 lines
12 KiB
TypeScript

import { Cause, Deferred, Effect, Exit, Fiber, Scope } from "effect"
import type { Diagnostic } from "../codemode.js"
import type { SafeObject } from "../tool-runtime.js"
import {
type AstNode,
CodeModeFunction,
CoercionFunction,
InterpreterRuntimeError,
ProgramThrow,
PromiseCapabilityFunction,
PromiseInstanceMethodReference,
PromiseMethodReference,
UriFunction,
} from "./model.js"
import { caughtErrorValue, normalizeError } from "./errors.js"
import { applyCollectionCallback, type CallbackRunner } from "./methods.js"
import { typeofValue } from "./references.js"
import { spreadItems } from "../stdlib/collections.js"
import { createAggregateErrorValue } from "../stdlib/value.js"
import { SandboxPromise } from "../values.js"
// Observation only controls rejection reporting; program completion interrupts all promise work.
export class PromiseRuntime<R> {
private readonly active = new Set<SandboxPromise>()
private readonly ids = new WeakMap<SandboxPromise, number>()
private readonly observed = new WeakSet<SandboxPromise>()
private readonly failures = new Map<number, Diagnostic>()
private nextID = 0
constructor(private readonly scope: Scope.Scope) {}
create(effect: Effect.Effect<unknown, unknown, R>): Effect.Effect<SandboxPromise, never, R> {
return Effect.suspend(() => {
// Allocate before forking so reruns get distinct IDs and diagnostics retain creation order.
const id = this.nextID++
return Effect.map(Effect.forkIn(effect, this.scope, { startImmediately: true }), (fiber) => {
const promise = new SandboxPromise(fiber)
this.active.add(promise)
this.ids.set(promise, id)
fiber.addObserver((exit) => {
this.active.delete(promise)
if (Exit.isSuccess(exit) || Cause.hasInterruptsOnly(exit.cause) || this.observed.has(promise)) {
this.ids.delete(promise)
return
}
const failure = normalizeError(Cause.squash(exit.cause))
this.failures.set(id, {
...failure,
message: `Unhandled rejection from an un-awaited promise: ${failure.message}`,
})
})
return promise
})
})
}
// Observation must be recorded when responsibility transfers, before the consumer fiber runs.
markObserved(promise: SandboxPromise): void {
this.observed.add(promise)
const id = this.ids.get(promise)
this.ids.delete(promise)
if (id !== undefined) this.failures.delete(id)
}
await(promise: SandboxPromise): Effect.Effect<Exit.Exit<unknown, unknown>> {
return Fiber.await(promise.fiber)
}
diagnostics(): Array<Diagnostic> {
return [...this.failures].sort(([left], [right]) => left - right).map(([, failure]) => failure)
}
// Re-check because a straggler can create promises before its interruption lands.
interrupt(): Effect.Effect<Array<Diagnostic>> {
const self = this
return Effect.gen(function* () {
while (self.active.size > 0) {
yield* Fiber.interruptAll([...self.active].map((promise) => promise.fiber))
}
return self.diagnostics()
})
}
}
export const selfResolutionError = (node?: AstNode): InterpreterRuntimeError =>
new InterpreterRuntimeError("Chaining cycle detected: a promise cannot resolve with itself.", node).as("TypeError")
export const invokePromiseMethod = <R>(
runner: CallbackRunner<R>,
promises: PromiseRuntime<R>,
ref: PromiseMethodReference,
args: Array<unknown>,
node: AstNode,
): Effect.Effect<unknown, unknown, R> => {
if (ref.name === "resolve") {
const value = args[0]
return value instanceof SandboxPromise ? Effect.succeed(value) : promises.create(Effect.succeed(value))
}
if (ref.name === "reject") {
return promises.create(Effect.fail(new ProgramThrow(args[0])))
}
const spread = spreadItems(args[0])
if (spread === undefined) {
return promises.create(
Effect.fail(
new InterpreterRuntimeError(
`Promise.${ref.name} expects an array of promises or plain values (e.g. Promise.${ref.name}(items.map((item) => tools.ns.tool(item)))).`,
node,
).as("TypeError"),
),
)
}
const items = Array.from(spread)
for (const item of items) {
if (item instanceof SandboxPromise) promises.markObserved(item)
}
switch (ref.name) {
case "all": {
const observations = items.map((item) =>
item instanceof SandboxPromise ? Effect.flatten(promises.await(item)) : Effect.succeed(item),
)
return promises.create(settleAfterTurn(Effect.all(observations, { concurrency: "unbounded" })))
}
case "allSettled": {
const observations = items.map((item) =>
item instanceof SandboxPromise ? promises.await(item) : Effect.succeed(Exit.succeed(item)),
)
return promises.create(
settleAfterTurn(
Effect.gen(function* () {
const outcomes: Array<unknown> = []
for (const observation of observations) {
const exit = yield* observation
if (Exit.isSuccess(exit)) {
outcomes.push(
Object.assign(Object.create(null) as SafeObject, { status: "fulfilled", value: exit.value }),
)
continue
}
if (Cause.hasInterruptsOnly(exit.cause)) {
// Teardown interruption is not a program-level rejection.
return yield* Effect.failCause(exit.cause)
}
outcomes.push(
Object.assign(Object.create(null) as SafeObject, {
status: "rejected",
reason: caughtErrorValue(Cause.squash(exit.cause)),
}),
)
}
return outcomes
}),
),
)
}
case "race": {
if (items.length === 0) {
return promises.create(
Effect.fail(
new InterpreterRuntimeError(
"Promise.race([]) would never settle; provide at least one promise or value.",
node,
),
),
)
}
const observations = items.map((item) =>
item instanceof SandboxPromise ? promises.await(item) : Effect.succeed(Exit.succeed(item)),
)
return promises.create(settleAfterTurn(Effect.flatten(Effect.raceAll(observations))))
}
case "any": {
const flipped = items.map((item) =>
item instanceof SandboxPromise
? Effect.flatMap(promises.await(item), (exit) => {
if (Exit.isSuccess(exit)) return Effect.fail(new PromiseAnyFulfilled(exit.value))
if (Cause.hasInterruptsOnly(exit.cause)) return Effect.failCause(exit.cause)
return Effect.succeed(caughtErrorValue(Cause.squash(exit.cause)))
})
: Effect.fail(new PromiseAnyFulfilled(item)),
)
const body = Effect.all(flipped, { concurrency: "unbounded" }).pipe(
Effect.flatMap((reasons) =>
Effect.fail(new ProgramThrow(createAggregateErrorValue(reasons, "All promises were rejected"))),
),
Effect.catch((error) =>
error instanceof PromiseAnyFulfilled ? Effect.succeed(error.value) : Effect.fail(error),
),
)
return promises.create(settleAfterTurn(body))
}
}
}
export const invokePromiseInstanceMethod = <R>(
runner: CallbackRunner<R>,
promises: PromiseRuntime<R>,
ref: PromiseInstanceMethodReference,
args: Array<unknown>,
node: AstNode,
): Effect.Effect<SandboxPromise, never, R> => {
const method = `Promise.prototype.${ref.name}`
promises.markObserved(ref.promise)
if (ref.name === "finally") {
return chainFinally(runner, promises, ref.promise, reactionHandler(args[0], method, node), method, node)
}
const onFulfilled = ref.name === "then" ? reactionHandler(args[0], method, node) : undefined
const onRejected = reactionHandler(ref.name === "then" ? args[1] : args[0], method, node)
return chainReaction(runner, promises, ref.promise, onFulfilled, onRejected, method, node)
}
export const constructPromise = <R>(
runner: CallbackRunner<R>,
promises: PromiseRuntime<R>,
executor: unknown,
node: AstNode,
): Effect.Effect<SandboxPromise, unknown, R> => {
if (!(executor instanceof CodeModeFunction)) {
throw new InterpreterRuntimeError(
"new Promise(...) expects an executor function (e.g. new Promise((resolve, reject) => { ... })).",
node,
).as("TypeError")
}
return Effect.gen(function* () {
const deferred = Deferred.makeUnsafe<unknown, unknown>()
const box: { own?: SandboxPromise } = {}
const promise = yield* promises.create(
Effect.flatMap(Deferred.await(deferred), (value) => {
if (!(value instanceof SandboxPromise)) return Effect.succeed(value)
if (value === box.own) return Effect.fail(selfResolutionError(node))
return runner.settlePromise(value)
}),
)
box.own = promise
const resolve = new PromiseCapabilityFunction((value) => {
Deferred.doneUnsafe(deferred, Exit.succeed(value))
})
const reject = new PromiseCapabilityFunction((value) => {
Deferred.doneUnsafe(deferred, Exit.fail(new ProgramThrow(value)))
})
const executed = yield* Effect.exit(runner.invokeFunction(executor, [resolve, reject]))
if (!Exit.isSuccess(executed)) {
if (Cause.hasInterruptsOnly(executed.cause)) return yield* Effect.failCause(executed.cause)
Deferred.doneUnsafe(deferred, Exit.fail(Cause.squash(executed.cause)))
}
return promise
})
}
// Settle one reaction turn after the deciding member, after its existing reactions.
const settleAfterTurn = <A, E, R>(body: Effect.Effect<A, E, R>): Effect.Effect<A, E, R> =>
Effect.flatMap(Effect.exit(body), (exit) => Effect.andThen(Effect.yieldNow, exit))
class PromiseAnyFulfilled {
constructor(readonly value: unknown) {}
}
type ReactionHandler = CodeModeFunction | CoercionFunction | UriFunction | PromiseCapabilityFunction
const reactionHandler = (value: unknown, method: string, node: AstNode): ReactionHandler | undefined => {
if (
value instanceof CodeModeFunction ||
value instanceof CoercionFunction ||
value instanceof UriFunction ||
value instanceof PromiseCapabilityFunction
) {
return value
}
if (typeofValue(value) === "function") {
throw new InterpreterRuntimeError(
`${method} handlers must be plain functions; wrap other callables in an arrow function, e.g. (value) => tools.ns.tool(value).`,
node,
)
}
return undefined
}
// Teardown bypasses handlers; settled reactions yield once so handlers never run inline.
const reactionExit = <R>(
promises: PromiseRuntime<R>,
source: SandboxPromise,
): Effect.Effect<Exit.Exit<unknown, unknown>, unknown, R> =>
Effect.gen(function* () {
const exit = yield* promises.await(source)
if (!Exit.isSuccess(exit) && Cause.hasInterruptsOnly(exit.cause)) return yield* Effect.failCause(exit.cause)
yield* Effect.yieldNow
return exit
})
const chainReaction = <R>(
runner: CallbackRunner<R>,
promises: PromiseRuntime<R>,
source: SandboxPromise,
onFulfilled: ReactionHandler | undefined,
onRejected: ReactionHandler | undefined,
method: string,
node: AstNode,
): Effect.Effect<SandboxPromise, never, R> => {
const box: { derived?: SandboxPromise } = {}
const body = Effect.gen(function* () {
const exit = yield* reactionExit(promises, source)
const handler = Exit.isSuccess(exit) ? onFulfilled : onRejected
if (handler === undefined) return yield* exit
const input = Exit.isSuccess(exit) ? exit.value : caughtErrorValue(Cause.squash(exit.cause))
const result = yield* applyCollectionCallback(runner, handler, method, node)([input])
if (result === box.derived) return yield* Effect.fail(selfResolutionError(node))
if (result instanceof SandboxPromise) return yield* runner.settlePromise(result)
return result
})
return Effect.map(promises.create(body), (derived) => {
box.derived = derived
return derived
})
}
const chainFinally = <R>(
runner: CallbackRunner<R>,
promises: PromiseRuntime<R>,
source: SandboxPromise,
cleanup: ReactionHandler | undefined,
method: string,
node: AstNode,
): Effect.Effect<SandboxPromise, never, R> =>
promises.create(
Effect.gen(function* () {
const exit = yield* reactionExit(promises, source)
if (cleanup !== undefined) {
const result = yield* applyCollectionCallback(runner, cleanup, method, node)([])
if (result instanceof SandboxPromise) yield* runner.settlePromise(result)
}
return yield* exit
}),
)