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fix(sfc): fix <script setup> async context preservation logic
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fix #4050
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@yyx990803
yyx990803 committed Jul 6, 2021
1 parent b68dfbb commit 03e2684
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Showing 4 changed files with 152 additions and 48 deletions.
20 changes: 15 additions & 5 deletions packages/compiler-sfc/__tests__/compileScript.spec.ts
View file
Expand Up @@ -847,6 +847,9 @@ const emit = defineEmits(['a', 'b'])
const { content } = compile(`<script setup>${code}</script>`, {
refSugar: true
})
if (shouldAsync) {
expect(content).toMatch(`let __temp, __restore`)
}
expect(content).toMatch(`${shouldAsync ? `async ` : ``}setup(`)
if (typeof expected === 'string') {
expect(content).toMatch(expected)
Expand All @@ -856,28 +859,35 @@ const emit = defineEmits(['a', 'b'])
}

test('expression statement', () => {
assertAwaitDetection(`await foo`, `await _withAsyncContext(foo)`)
assertAwaitDetection(
`await foo`,
`;(([__temp,__restore]=_withAsyncContext(()=>(foo))),__temp=await __temp,__restore())`
)
})

test('variable', () => {
assertAwaitDetection(
`const a = 1 + (await foo)`,
`1 + (await _withAsyncContext(foo))`
`1 + ((([__temp,__restore]=_withAsyncContext(()=>(foo))),__temp=await __temp,__restore(),__temp))`
)
})

test('ref', () => {
assertAwaitDetection(
`ref: a = 1 + (await foo)`,
`1 + (await _withAsyncContext(foo))`
`1 + ((([__temp,__restore]=_withAsyncContext(()=>(foo))),__temp=await __temp,__restore(),__temp))`
)
})

test('nested statements', () => {
assertAwaitDetection(`if (ok) { await foo } else { await bar }`, code => {
return (
code.includes(`await _withAsyncContext(foo)`) &&
code.includes(`await _withAsyncContext(bar)`)
code.includes(
`;(([__temp,__restore]=_withAsyncContext(()=>(foo))),__temp=await __temp,__restore())`
) &&
code.includes(
`;(([__temp,__restore]=_withAsyncContext(()=>(bar))),__temp=await __temp,__restore())`
)
)
})
})
Expand Down
39 changes: 30 additions & 9 deletions packages/compiler-sfc/src/compileScript.ts
View file
Expand Up @@ -32,7 +32,8 @@ import {
LabeledStatement,
CallExpression,
RestElement,
TSInterfaceBody
TSInterfaceBody,
AwaitExpression
} from '@babel/types'
import { walk } from 'estree-walker'
import { RawSourceMap } from 'source-map'
Expand Down Expand Up @@ -487,6 +488,25 @@ export function compileScript(
})
}

/**
* await foo()
* -->
* (([__temp, __restore] = withAsyncContext(() => foo())),__temp=await __temp,__restore(),__temp)
*/
function processAwait(node: AwaitExpression, isStatement: boolean) {
s.overwrite(
node.start! + startOffset,
node.argument.start! + startOffset,
`${isStatement ? `;` : ``}(([__temp,__restore]=${helper(
`withAsyncContext`
)}(()=>(`
)
s.appendLeft(
node.end! + startOffset,
`))),__temp=await __temp,__restore()${isStatement ? `` : `,__temp`})`
)
}

function processRefExpression(exp: Expression, statement: LabeledStatement) {
if (exp.type === 'AssignmentExpression') {
const { left, right } = exp
Expand Down Expand Up @@ -949,17 +969,13 @@ export function compileScript(
node.type.endsWith('Statement')
) {
;(walk as any)(node, {
enter(node: Node) {
if (isFunction(node)) {
enter(child: Node, parent: Node) {
if (isFunction(child)) {
this.skip()
}
if (node.type === 'AwaitExpression') {
if (child.type === 'AwaitExpression') {
hasAwait = true
s.prependRight(
node.argument.start! + startOffset,
helper(`withAsyncContext`) + `(`
)
s.appendLeft(node.argument.end! + startOffset, `)`)
processAwait(child, parent.type === 'ExpressionStatement')
}
}
})
Expand Down Expand Up @@ -1151,6 +1167,11 @@ export function compileScript(
if (propsIdentifier) {
s.prependRight(startOffset, `\nconst ${propsIdentifier} = __props`)
}
// inject temp variables for async context preservation
if (hasAwait) {
const any = isTS ? `:any` : ``
s.prependRight(startOffset, `\nlet __temp${any}, __restore${any}\n`)
}

const destructureElements =
hasDefineExposeCall || !options.inlineTemplate ? [`expose`] : []
Expand Down
94 changes: 80 additions & 14 deletions packages/runtime-core/__tests__/apiSetupHelpers.spec.ts
View file
Expand Up @@ -119,12 +119,20 @@ describe('SFC <script setup> helpers', () => {

const Comp = defineComponent({
async setup() {
let __temp: any, __restore: any

beforeInstance = getCurrentInstance()
const msg = await withAsyncContext(
new Promise(r => {
resolve = r
})
)

const msg = (([__temp, __restore] = withAsyncContext(
() =>
new Promise(r => {
resolve = r
})
)),
(__temp = await __temp),
__restore(),
__temp)

// register the lifecycle after an await statement
onMounted(spy)
afterInstance = getCurrentInstance()
Expand Down Expand Up @@ -155,13 +163,18 @@ describe('SFC <script setup> helpers', () => {

const Comp = defineComponent({
async setup() {
let __temp: any, __restore: any

beforeInstance = getCurrentInstance()
try {
await withAsyncContext(
new Promise((r, rj) => {
reject = rj
})
;[__temp, __restore] = withAsyncContext(
() =>
new Promise((_, rj) => {
reject = rj
})
)
__temp = await __temp
__restore()
} catch (e) {
// ignore
}
Expand Down Expand Up @@ -206,11 +219,20 @@ describe('SFC <script setup> helpers', () => {

const Comp = defineComponent({
async setup() {
let __temp: any, __restore: any

beforeInstance = getCurrentInstance()

// first await
await withAsyncContext(Promise.resolve())
;[__temp, __restore] = withAsyncContext(() => Promise.resolve())
__temp = await __temp
__restore()

// setup exit, instance set to null, then resumed
await withAsyncContext(doAsyncWork())
;[__temp, __restore] = withAsyncContext(() => doAsyncWork())
__temp = await __temp
__restore()

afterInstance = getCurrentInstance()
return () => {
resolve()
Expand All @@ -237,8 +259,13 @@ describe('SFC <script setup> helpers', () => {

const Comp = defineComponent({
async setup() {
await withAsyncContext(Promise.resolve())
await withAsyncContext(Promise.reject())
let __temp: any, __restore: any
;[__temp, __restore] = withAsyncContext(() => Promise.resolve())
__temp = await __temp
__restore()
;[__temp, __restore] = withAsyncContext(() => Promise.reject())
__temp = await __temp
__restore()
},
render() {}
})
Expand All @@ -256,6 +283,42 @@ describe('SFC <script setup> helpers', () => {
expect(getCurrentInstance()).toBeNull()
})

// #4050
test('race conditions', async () => {
const uids = {
one: { before: NaN, after: NaN },
two: { before: NaN, after: NaN }
}

const Comp = defineComponent({
props: ['name'],
async setup(props: { name: 'one' | 'two' }) {
let __temp: any, __restore: any

uids[props.name].before = getCurrentInstance()!.uid
;[__temp, __restore] = withAsyncContext(() => Promise.resolve())
__temp = await __temp
__restore()

uids[props.name].after = getCurrentInstance()!.uid
return () => ''
}
})

const app = createApp(() =>
h(Suspense, () =>
h('div', [h(Comp, { name: 'one' }), h(Comp, { name: 'two' })])
)
)
const root = nodeOps.createElement('div')
app.mount(root)

await new Promise(r => setTimeout(r))
expect(uids.one.before).not.toBe(uids.two.before)
expect(uids.one.before).toBe(uids.one.after)
expect(uids.two.before).toBe(uids.two.after)
})

test('should teardown in-scope effects', async () => {
let resolve: (val?: any) => void
const ready = new Promise(r => {
Expand All @@ -266,7 +329,10 @@ describe('SFC <script setup> helpers', () => {

const Comp = defineComponent({
async setup() {
await withAsyncContext(Promise.resolve())
let __temp: any, __restore: any
;[__temp, __restore] = withAsyncContext(() => Promise.resolve())
__temp = await __temp
__restore()

c = computed(() => {})
// register the lifecycle after an await statement
Expand Down
47 changes: 27 additions & 20 deletions packages/runtime-core/src/apiSetupHelpers.ts
View file
@@ -1,9 +1,9 @@
import { isPromise } from '../../shared/src'
import {
getCurrentInstance,
setCurrentInstance,
SetupContext,
createSetupContext,
setCurrentInstance
createSetupContext
} from './component'
import { EmitFn, EmitsOptions } from './componentEmits'
import {
Expand Down Expand Up @@ -230,25 +230,32 @@ export function mergeDefaults(
}

/**
* Runtime helper for storing and resuming current instance context in
* async setup().
* `<script setup>` helper for persisting the current instance context over
* async/await flows.
*
* `@vue/compiler-sfc` converts the following:
*
* ```ts
* const x = await foo()
* ```
*
* into:
*
* ```ts
* let __temp, __restore
* const x = (([__temp, __restore] = withAsyncContext(() => foo())),__temp=await __temp,__restore(),__temp)
* ```
* @internal
*/
export function withAsyncContext<T>(awaitable: T | Promise<T>): Promise<T> {
export function withAsyncContext(getAwaitable: () => any) {
const ctx = getCurrentInstance()
setCurrentInstance(null) // unset after storing instance
if (__DEV__ && !ctx) {
warn(`withAsyncContext() called when there is no active context instance.`)
let awaitable = getAwaitable()
setCurrentInstance(null)
if (isPromise(awaitable)) {
awaitable = awaitable.catch(e => {
setCurrentInstance(ctx)
throw e
})
}
return isPromise<T>(awaitable)
? awaitable.then(
res => {
setCurrentInstance(ctx)
return res
},
err => {
setCurrentInstance(ctx)
throw err
}
)
: (awaitable as any)
return [awaitable, () => setCurrentInstance(ctx)]
}

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