Simplify baseDiskName()

Refrain from dealing with the impossible "self-referencing" scoped disk case. Instead of that, test the inline parent behavior.

Also update the exception message in forgetDisks() so that it's a bit less vague.

src/Bootstrappers/FilesystemTenancyBootstrapper.php

@@ -132,12 +132,10 @@ class FilesystemTenancyBootstrapper implements TenancyBootstrapper
                 continue;
             }
 
-            $baseDisk = static::baseDiskName($name);
-
-            if (in_array($baseDisk, $tenantDisks, true)) {
+            if (in_array(static::baseDiskName($name), $tenantDisks, true)) {
                 $scopedDisks[] = $name;
             } elseif (in_array($name, $tenantDisks, true)) {
-                throw new Exception("A disk using the 'scoped' driver cannot be tenant-aware. List its base disk in tenancy.filesystem.disks instead.");
+                throw new Exception("Disk [$name] uses the 'scoped' driver, so it has no root to make tenant-aware. List its base disk in tenancy.filesystem.disks instead.");
             }
         }
 
@@ -359,27 +357,17 @@ class FilesystemTenancyBootstrapper implements TenancyBootstrapper
      * Disks using the 'scoped' driver have no root or url of their own -- they inherit those from their parent disk,
      * which can be scoped as well, so only the final/base parent has to be tenant-aware.
      *
-     * Returns null if the chain doesn't end with a named disk, i.e. when a parent disk is
-     * configured inline or when the disks reference each other.
+     * Returns null if the base disk has no name, i.e. when the disk is configured inline as an array.
      */
     public static function baseDiskName(string $disk): string|null
     {
-        // Keep track of visited disks to avoid infinite loops in case of disks referencing each other
-        $visited = [];
-
         while (config("filesystems.disks.$disk.driver") === 'scoped') {
-            if (in_array($disk, $visited, true)) {
-                // The disk and its parents reference each other, invalid
-                return null;
-            }
-
-            $visited[] = $disk;
-            $disk = config("filesystems.disks.$disk.disk");
-
-            if (! is_string($disk)) {
+            if (! is_string($parent = config("filesystems.disks.$disk.disk"))) {
                 // Laravel allows configuring the parent disk inline as an array, and such a disk has no name
                 return null;
             }
+
+            $disk = $parent;
         }
 
         return $disk;

tests/Bootstrappers/FilesystemTenancyBootstrapperTest.php

@@ -341,35 +341,33 @@ test('adding a scoped disk to tenancy.filesystem.disks throws an exception if it
             'disk' => 'foo',
             'prefix' => 'bar',
         ],
-        // Disks referencing each other (neither has a base disk)
-        'filesystems.disks.abc' => [
+        // Scoped disk with an inline parent
+        'filesystems.disks.inline_parent' => [
             'driver' => 'scoped',
-            'disk' => 'def',
-            'prefix' => 'abc',
+            'disk' => [
+                'driver' => 'local',
+                'root' => storage_path('app/inline'),
             ],
-        'filesystems.disks.def' => [
-            'driver' => 'scoped',
-            'disk' => 'abc',
-            'prefix' => 'def',
+            'prefix' => 'inline_parent',
         ],
         'tenancy.filesystem.disks' => [$disk],
     ]);
 
     expect(fn () => tenancy()->initialize(Tenant::create()))
-        ->toThrow(Exception::class, "List its base disk in tenancy.filesystem.disks instead");
+        ->toThrow(Exception::class, "Disk [$disk] uses the 'scoped' driver, so it has no root to make tenant-aware.");
 
-    // Parent of 'abc' is 'def', whose parent is 'abc' -- there's no base disk for these, so these are
-    // still invalid and the exception will still be thrown.
-    if ($disk !== 'abc') {
+    // 'inline_parent' has no base disk name to list, so there's no way to make it tenant-aware
+    // and the exception is thrown regardless of what's listed.
+    if ($disk !== 'inline_parent') {
         config(['tenancy.filesystem.disks' => ['public', $disk]]);
 
         expect(fn () => tenancy()->initialize(Tenant::create()))
-            ->not()->toThrow(Exception::class, "List its base disk in tenancy.filesystem.disks instead");
+            ->not()->toThrow(Exception::class, "Disk [$disk] uses the 'scoped' driver, so it has no root to make tenant-aware.");
     }
 })->with([
     'scoped disk' => 'foo',
     'nested scoped disk' => 'bar',
-    'scoped disk with no base disk' => 'abc',
+    'scoped disk with an inline base disk' => 'inline_parent',
 ]);
 
 test('adding a scoped disk to tenancy.filesystem.disks has no effect on the disk when its base disk is listed too', function () {
@@ -401,31 +399,6 @@ test('adding a scoped disk to tenancy.filesystem.disks has no effect on the disk
     ]);
 });
 
-test('scoped disks referencing each other do not make bootstrapper hang', function () {
-    config([
-        'tenancy.bootstrappers' => [
-            FilesystemTenancyBootstrapper::class,
-        ],
-        'filesystems.disks.foo' => [
-            'driver' => 'scoped',
-            'disk' => 'bar',
-            'prefix' => 'foo',
-        ],
-        'filesystems.disks.bar' => [
-            'driver' => 'scoped',
-            'disk' => 'foo',
-            'prefix' => 'bar',
-        ],
-    ]);
-
-    expect(FilesystemTenancyBootstrapper::baseDiskName('foo'))->toBeNull();
-    expect(FilesystemTenancyBootstrapper::baseDiskName('bar'))->toBeNull();
-
-    tenancy()->initialize(Tenant::create());
-
-    expect(tenant())->not()->toBeNull();
-});
-
 test('file cache stores get their paths scoped on bootstrap and restored back on revert', function () {
     $fooPath = storage_path('framework/cache/foo_file');
     $barPath = storage_path('framework/cache/bar_file');