App\Models\ must return a relationship instance - php

Question

I am trying to run some dynamic method calls based on the value of a database field. Some context: I have a model Anniversary and I want to display all upcoming anniversaries within the next x days. An anniversary has a date and a frequency. For example, monthly, quarterly, etc. Based on the frequency, I want to check for each anniversary if it is upcoming.
Here is my code so far:
$anniversaries = auth()->user()->anniversaries()->get();
$test = $anniversaries->filter(function ($anniversary) {
$method = Str::of($anniversary->frequency)->camel();
return ${$anniversary->$method}() == true;
});
dd($test);
The above works, when in the actual method I dd() something. But when returning true or false, I get the error:
App\Models\Anniversary::monthly must return a relationship instance
And in my model I just have a few methods like below, for testing:
public function monthly()
{
return true;
}
public function quarterly()
{
return false;
}
My only question is, I want to understand why I am getting this error and ofcourse any pointers in the right direction to get what I want to work. Thanks!

Answer 1

The following line creates an Illuminate\Support\Str object instead of a string. This causes the Method name must be a string error.
$method = Str::of($anniversary->frequency)->camel();
You can fix this by manually casting it to a string and invoking it directly:
$test = $anniversaries->filter(function ($anniversary) {
$method = (string) (Str::of($anniversary->frequency)->camel());
return $anniversary->$method() == true;
});

Answer 2

Throwing in my 2 cents for this as well. The Str::of(), which are "Fluent Strings" added in Laravel 7.x return an instance of Stringable:
https://laravel.com/api/8.x/Illuminate/Support/Stringable.html
For example:
dd(Str::of('monthly')->camel());
Illuminate\Support\Stringable {#3444
value: "monthly"
}
To get the value of this, as a string and not an object, you can cast it (as shown in MaartenDev's answer), or call the __toString() method:
dd(Str::of('monthly')->camel()->__toString());
"monthly"
In your code example, that would simply be:
$method = Str::of($anniversary->frequency)->camel()->__toString();
return $anniversary->{$method}() == true;
Alternatively, you can just use the Str::camel() function to bypass this Stringable class:
$method = Str::camel($anniversary->frequency);
return $anniversary->{$method}() == true;
https://laravel.com/docs/8.x/helpers#method-camel-case
Hope that helps clear up some confusion 😄

Answer 3

you have issue in this part ${$anniversary->$method}(). if you access a function like property laravel models thinks its relation function.
so replace with $anniversary->{$method}()
try this one
$anniversaries = auth()->user()->anniversaries()->get();
$test = $anniversaries->filter(function ($anniversary) {
$method = Str::of($anniversary->frequency)->camel();
return $anniversary->{$method}() == true;
});
dd($test);