fix: Invalidate the key when mutating without revalidating

src/use-swr.ts

@@ -140,9 +140,13 @@ export const useSWRHandler = <Data = any, Error = any>(
         key === keyRef.current &&
         initialMountedRef.current
 
-      const cleanupState = () => {
-        delete CONCURRENT_PROMISES[key]
-        delete CONCURRENT_PROMISES_TS[key]
+      const cleanupState = (ts: number) => {
+        // CONCURRENT_PROMISES_TS[key] might be overridden, check if it's still
+        // the same request before deleting.
+        if (CONCURRENT_PROMISES_TS[key] === ts) {
+          delete CONCURRENT_PROMISES[key]
+          delete CONCURRENT_PROMISES_TS[key]
+        }
       }
 
       // Start fetching. Change the `isValidating` state, update the cache.
@@ -184,12 +188,7 @@ export const useSWRHandler = <Data = any, Error = any>(
         if (shouldStartNewRequest) {
           // If the request isn't interrupted, clean it up after the
           // deduplication interval.
-          setTimeout(() => {
-            // CONCURRENT_PROMISES_TS[key] maybe be `undefined`.
-            if (CONCURRENT_PROMISES_TS[key] === startAt) {
-              cleanupState()
-            }
-          }, config.dedupingInterval)
+          setTimeout(() => cleanupState(startAt), config.dedupingInterval)
 
           // Trigger the successful callback.
           if (isCallbackSafe()) {
@@ -262,7 +261,8 @@ export const useSWRHandler = <Data = any, Error = any>(
           broadcastState(cache, key, newData, newState.error, false)
         }
       } catch (err) {
-        cleanupState()
+        // Reset the state immediately.
+        cleanupState(startAt!)
         cache.set(keyValidating, false)
         if (getConfig().isPaused()) {
           setState({

src/utils/broadcast-state.ts

@@ -10,9 +10,14 @@ export const broadcastState: Broadcaster = (
   isValidating,
   revalidate
 ) => {
-  const [EVENT_REVALIDATORS, STATE_UPDATERS] = SWRGlobalState.get(
-    cache
-  ) as GlobalState
+  const [
+    EVENT_REVALIDATORS,
+    STATE_UPDATERS,
+    ,
+    ,
+    CONCURRENT_PROMISES,
+    CONCURRENT_PROMISES_TS
+  ] = SWRGlobalState.get(cache) as GlobalState
   const revalidators = EVENT_REVALIDATORS[key]
   const updaters = STATE_UPDATERS[key]
 
@@ -24,10 +29,17 @@ export const broadcastState: Broadcaster = (
   }
 
   // If we also need to revalidate, only do it for the first hook.
-  if (revalidate && revalidators && revalidators[0]) {
-    return revalidators[0](revalidateEvents.MUTATE_EVENT).then(() =>
-      cache.get(key)
-    )
+  if (revalidate) {
+    // Invalidate the key by deleting the concurrent request markers so new
+    // requests will not be deduped.
+    delete CONCURRENT_PROMISES[key]
+    delete CONCURRENT_PROMISES_TS[key]
+
+    if (revalidators && revalidators[0]) {
+      return revalidators[0](revalidateEvents.MUTATE_EVENT).then(() =>
+        cache.get(key)
+      )
+    }
   }
 
   return cache.get(key)

src/utils/mutate.ts

@@ -19,8 +19,9 @@ export const internalMutate = async <Data>(
     cache
   ) as GlobalState
 
-  // if there is no new data to update, let's just revalidate the key
+  // If there is no new data to update, we revalidate the key.
   if (isUndefined(_data)) {
+    // Revalidate and broadcast state.
     return broadcastState(
       cache,
       key,

test/use-swr-integration.test.tsx

@@ -373,4 +373,35 @@ describe('useSWR', () => {
     expect(fetcher).toBeCalled()
     await screen.findByText('hello, SWR')
   })
+
+  it('should revalidate on mount after dedupingInterval', async () => {
+    const key = createKey()
+    let cnt = 0
+
+    function Foo() {
+      const { data } = useSWR(key, () => 'data: ' + cnt++, {
+        dedupingInterval: 0
+      })
+      return <>{data}</>
+    }
+
+    function Page() {
+      const [showFoo, setShowFoo] = React.useState(true)
+      return (
+        <>
+          {showFoo ? <Foo /> : null}
+          <button onClick={() => setShowFoo(!showFoo)}>toggle</button>
+        </>
+      )
+    }
+
+    renderWithConfig(<Page />)
+    await waitForNextTick()
+    screen.getByText('data: 0')
+    fireEvent.click(screen.getByText('toggle'))
+    await waitForNextTick()
+    fireEvent.click(screen.getByText('toggle'))
+    await act(() => sleep(20))
+    screen.getByText('data: 1')
+  })
 })

test/use-swr-revalidate.test.tsx

@@ -1,12 +1,13 @@
 import { act, fireEvent, screen } from '@testing-library/react'
 import React from 'react'
-import useSWR from 'swr'
+import useSWR, { useSWRConfig } from 'swr'
 import {
   createResponse,
   sleep,
   nextTick as waitForNextTick,
   createKey,
-  renderWithConfig
+  renderWithConfig,
+  nextTick
 } from './utils'
 
 describe('useSWR - revalidate', () => {
@@ -162,4 +163,39 @@ describe('useSWR - revalidate', () => {
     renderWithConfig(<Page />)
     screen.getByText('false')
   })
+
+  it('should mark the key as invalidated and clear deduping with `mutate`, even if there is no mounted hook', async () => {
+    const key = createKey()
+    let cnt = 0
+
+    function Foo() {
+      const { data } = useSWR(key, () => 'data: ' + cnt++, {
+        dedupingInterval: 1000
+      })
+      return <>{data}</>
+    }
+
+    function Page() {
+      const [showFoo, setShowFoo] = React.useState(true)
+      const { mutate } = useSWRConfig()
+      return (
+        <>
+          {showFoo ? <Foo /> : null}
+          <button onClick={() => setShowFoo(!showFoo)}>toggle</button>
+          <button onClick={() => mutate(key)}>mutate</button>
+        </>
+      )
+    }
+
+    renderWithConfig(<Page />)
+    await nextTick()
+    screen.getByText('data: 0')
+    fireEvent.click(screen.getByText('toggle'))
+    await nextTick()
+    fireEvent.click(screen.getByText('mutate'))
+    await nextTick()
+    fireEvent.click(screen.getByText('toggle'))
+    await act(() => sleep(20))
+    screen.getByText('data: 1')
+  })
 })