[Fix] Changing a site's branch no longer checks out the live release under modern deployment

app/Actions/Site/UpdateBranch.php

@@ -10,6 +10,9 @@
 class UpdateBranch
 {
     /**
+     * With modern deployment the site path is the live release, so the branch
+     * is switched in the source checkout and the next deployment clones it.
+     *
      * @param  array<string, mixed>  $input
      *
      * @throws SSHError
@@ -21,8 +24,9 @@ public function update(Site $site, array $input): void
         ])->validate();
 
         $site->branch = $input['branch'];
-        app(Git::class)->fetchOrigin($site);
-        app(Git::class)->checkout($site);
+        $path = $site->modernDeploymentEnabled() ? $site->basePath().'/source' : null;
+        app(Git::class)->fetchOrigin($site, $path);
+        app(Git::class)->checkout($site, $path);
         $site->save();
     }
 }

app/SSH/OS/Git.php

@@ -38,11 +38,11 @@ public function clone(Site $site, ?string $path = null): void
     /**
      * @throws SSHError
      */
-    public function checkout(Site $site): void
+    public function checkout(Site $site, ?string $path = null): void
     {
         $site->server->ssh($site->user)->exec(
             view('ssh.git.checkout', [
-                'path' => escapeshellarg((string) $site->path),
+                'path' => escapeshellarg((string) ($path ?? $site->path)),
                 'branch' => escapeshellarg((string) $site->branch),
             ]),
             'checkout-branch',
@@ -53,7 +53,7 @@ public function checkout(Site $site): void
     /**
      * @throws SSHError
      */
-    public function fetchOrigin(Site $site): void
+    public function fetchOrigin(Site $site, ?string $path = null): void
     {
         $ssh = $site->server->ssh($site->user);
 
@@ -63,7 +63,7 @@ public function fetchOrigin(Site $site): void
 
         $ssh->exec(
             view('ssh.git.fetch-origin', [
-                'path' => escapeshellarg((string) $site->path),
+                'path' => escapeshellarg((string) ($path ?? $site->path)),
             ]),
             'fetch-origin',
             $site->id

tests/Feature/SitesTest.php

@@ -559,6 +559,35 @@
     SSH::assertExecutedContains("git checkout -f 'master'");
 });
 
+test('change branch with modern deployment checks out the source, not the live release', function () {
+    SSH::fake();
+
+    $this->site->update([
+        'path' => '/home/vito/vito.test/current',
+        'type_data' => [
+            'modern_deployment' => true,
+            'modern_deployment_history' => 10,
+            'modern_deployment_shared_resources' => ['.env', 'storage'],
+        ],
+    ]);
+
+    $this->actingAs($this->user);
+
+    $this->patch(route('site-settings.update-branch', [
+        'server' => $this->server->id,
+        'site' => $this->site,
+    ]), [
+        'branch' => 'develop',
+    ])
+        ->assertSessionDoesntHaveErrors();
+
+    expect($this->site->refresh()->branch)->toEqual('develop');
+
+    SSH::assertExecutedContains("cd '/home/vito/vito.test/source'");
+    SSH::assertExecutedContains("git checkout -f 'develop'");
+    SSH::assertNotExecutedContains("cd '/home/vito/vito.test/current'");
+});
+
 test('update web directory', function () {
     SSH::fake();