count(): parameter must be an array or an object that implements countable (view: )

1. Error: count(): parameter must be an array or an object that implements countable (view: ). as shown in Figure 1

Figure 1

2. Check the code implementation

count($user->address_book);

3. Print $user->address_book, its value is null

4. Adjust the code implementation, when $user->address_book is null, the expression $user->address_book ??[]equivalent to[], otherwise it is $user->address_book.

count($user->address_book ?? []);

5. In PHP 7.2.0, when the value parameter is passed into the invalid countable type, count() will now generate a warning. The version of the environment where the error occurred is PHP 7.4.26