fix: check "if (!error)" skip error if value is cast to false (#4118)

Co-authored-by: Viktor Grachev <[email protected]>

Author: vtgrachev

src/_internal/utils/mutate.ts

@@ -123,6 +123,7 @@ export async function internalMutate<Data>(
 
     let data: any = _data
     let error: unknown
+    let isError = false
 
     // Update global timestamps.
     const beforeMutationTs = getTimestamp()
@@ -155,6 +156,7 @@ export async function internalMutate<Data>(
       } catch (err) {
         // If it throws an error synchronously, we shouldn't update the cache.
         error = err
+        isError = true
       }
     }
 
@@ -164,15 +166,16 @@ export async function internalMutate<Data>(
       // avoid race conditions.
       data = await (data as Promise<Data>).catch(err => {
         error = err
+        isError = true
       })
 
       // Check if other mutations have occurred since we've started this mutation.
       // If there's a race we don't update cache or broadcast the change,
       // just return the data.
       if (beforeMutationTs !== MUTATION[key][0]) {
-        if (error) throw error
+        if (isError) throw error
         return data
-      } else if (error && hasOptimisticData && rollbackOnError(error)) {
+      } else if (isError && hasOptimisticData && rollbackOnError(error)) {
         // Rollback. Always populate the cache in this case but without
         // transforming the data.
         populateCache = true
@@ -184,7 +187,7 @@ export async function internalMutate<Data>(
 
     // If we should write back the cache after request.
     if (populateCache) {
-      if (!error) {
+      if (!isError) {
         // Transform the result into data.
         if (isFunction(populateCache)) {
           const populateCachedData = populateCache(data, committedData)
@@ -207,7 +210,7 @@ export async function internalMutate<Data>(
     })
 
     // Throw error or return data
-    if (error) {
+    if (isError) {
       if (throwOnError) throw error
       return
     }

test/use-swr-remote-mutation.test.tsx

@@ -1112,4 +1112,32 @@ describe('useSWR - remote mutation', () => {
 
     expect(error.message).toBe('Can’t trigger the mutation: missing key.')
   })
+
+  it('should call `onError` and `onRejected` but do not call `onSuccess` if value an error is cast to false', async () => {
+    const key = createKey()
+    const onSuccess = jest.fn()
+    const onError = jest.fn()
+    const onRejected = jest.fn()
+
+    const fetcher = () => {
+      return new Promise((_, reject) => reject(''));
+    };
+
+    function Page() {
+      const { trigger } = useSWRMutation(key, fetcher, { onError, onSuccess })
+
+      return <button onClick={() => trigger().catch(onRejected)}>trigger</button>
+    }
+
+    render(<Page />)
+
+    await screen.findByText('trigger')
+    fireEvent.click(screen.getByText('trigger'))
+
+    await nextTick()
+
+    expect(onSuccess).not.toHaveBeenCalled()
+    expect(onError).toHaveBeenCalled()
+    expect(onRejected).toHaveBeenCalled()
+  })
 })