[12.x] Track filesystem adapter decoration

[daniser]

This PR fixes discrepancy between Flysystem adapter passed as a 2nd argument to Laravel adapter, and actual used adapter in case it was decorated by ReadOnlyFilesystemAdapter and/or PathPrefixedAdapter within createFlysystem method.
It was done by passing FlysystemAdapter into createFlysystem by reference.

[taylorotwell]

Aren't objects passed by reference in PHP by default. 👀

[daniser]

Aren't objects passed by reference in PHP by default. 👀

I asked myself this question too. Test results differ nevertheless.
I think in PHP world it is something like C's "pointer to a pointer".

[macropay-solutions]

Aren't objects passed by reference in PHP by default. 👀

I asked myself this question too. Test results differ nevertheless. I think in PHP world it is something like C's "pointer to a pointer".

@daniser This could happen if the $adapter variable is overwritten instead of the object being altered.

And in fact that is exactly what is happening

        if (($config['read-only'] ?? false) === true) {
            $adapter = new ReadOnlyFilesystemAdapter($adapter);
        }

        if (!empty($config['prefix'])) {
            $adapter = new PathPrefixedAdapter($adapter, $config['prefix']);
        }

[SyuTingSong]

I was troubled by this pass-by-reference adapter last week, because I have some application-level logic that needs to check what type the underlying adapter is.

Some want to retrieve the decorated adapter, while others want to retrieve the underlying adapter before decoration. Directly modifying the adapter is not a good solution.

@daniser \Illuminate\Filesystem\FilesystemAdapter provides a getDriver method that allows you to obtain the instance of \League\Flysystem\Filesystem. I am not sure if this will help as the flysystem refuses to provide a getAdapter method to retrieve the underlying decorated adapter.

[daniser]

Some want to retrieve the decorated adapter, while others want to retrieve the underlying adapter before decoration. Directly modifying the adapter is not a good solution.

This is exactly what I wanted (decorated adapter), unfortunately my change was short-sighted and I broke people's setups (sorry).
For now I rolled back to using reflection to retrieve adapter from a driver.