isValidating stays true after 2nd failed request

[mtakac]

I am trying to implement login using swr, but if my login request fails 2 times in a row isValidating gets stuck and returns true even after the request alredy finished.

Expected behaviour:

I try to login with incorrect credentials
Login request fails
isValidating is set to false no matter how many times the request already failed

Current behaviour:

I try to login with incorrect credentials
Login request fails
isValidating is set to false
But if I try to login with incorrect credentials again
Login request fails
isValidating is not set to false anymore

This is my login component (simplified):

const LoginForm = React.FC () => {
  const [email, setEmail] = useState<string>();
  const [password, setPassword] = useState<string>();
  const [shouldSubmit, setShouldSubmit] = useState(false);

  const { data, error, isValidating } = useSWR(
    shouldSubmit ? ['/signIn', email, password] : null,
    (url, email, password) => authenticationApi.signIn(email, password) 
  );

  useEffect(() => {
    if (!error) return;

    setShouldSubmit(false);
    alert('Invalid email and / or password.');
  }, [error]);

  return (
    <View style={styles.signInForm}>
      <TextInput
        label="Email"
        value={email}
        onChangeText={value => setEmail(value)}
      />
      <TextInput
        label="Password"
        value={password}
        onChangeText={value => setPassword(value)}
        secureTextEntry
      />

      <Button
        mode="contained"
        onPress={() => setShouldSubmit(true)}
      >
        Sign in
      </Button>
    </View>
  );
}

[dominictwlee]

@quietshu The issue seems to be related to dispatch being reassigned to () => null during cleanup , which gets called before useEffect runs the 2nd time round.

Is there any reason why it's being reassigned that way, and can that be safely removed? If so happy to make a PR for it. Wouldn't it make more sense to just use a plain function rather than useCallback in this case for dispatch?

[shuding]

Should be fixed with #1396 🙏