fix: Prevent unneeded blog switching in multisite env. (#2781)

* rework switch_to_blog method
* remove dump paste
* remove error log, see #2210
* Make suggested typecast changes by @gchtr
* Get short version of get_blog_details()
* remove extra int cast
* proposed fixes for multisite tests

src/Site.php

@@ -217,17 +217,30 @@ public function wp_object(): ?WP_Site
     /**
      * Switches to the blog requested in the request
      *
-     * @param string|integer|null $site_name_or_id
+     * @param string|integer|null $blog_identifier The name or ID of the blog to switch to. If `null`, the current blog.
      * @return integer with the ID of the new blog
      */
-    protected static function switch_to_blog($site_name_or_id)
+    protected static function switch_to_blog($blog_identifier = null): int
     {
-        if ($site_name_or_id === null) {
-            $site_name_or_id = \get_current_blog_id();
+        $current_id = \get_current_blog_id();
+
+        if ($blog_identifier === null) {
+            $blog_identifier = $current_id;
+        }
+
+        $info = \get_blog_details($blog_identifier, false);
+
+        if (false === $info) {
+            return $current_id;
         }
-        $info = \get_blog_details($site_name_or_id);
-        \switch_to_blog($info->blog_id);
-        return $info->blog_id;
+
+        $blog_identifier = $info->blog_id;
+
+        if ((int) $current_id !== (int) $blog_identifier) {
+            \switch_to_blog($blog_identifier);
+        }
+
+        return (int) $blog_identifier;
     }
 
     /**

tests/test-timber-multisite.php

@@ -53,6 +53,7 @@ public function testPostGettingAcrossSites()
             $this->factory->post->create([
                 'post_title' => array_pop($post_titles),
             ]);
+            restore_current_blog();
         }
 
         $timber_posts = [];
@@ -108,6 +109,7 @@ public function testPostGettingAcrossSitesNoArgs()
             $this->factory->post->create([
                 'post_title' => 'Zebras are good on site ID = ' . $site_id,
             ]);
+            restore_current_blog();
         }
         $this->go_to('/');
         $timber_posts = [];
@@ -144,8 +146,11 @@ public function testPostSearchAcrossSites()
             return;
         }
         $site_ids[] = self::createSubDomainSite('foo.example.org', 'My Foo');
+        restore_current_blog();
         $site_ids[] = self::createSubDomainSite('quack.example.org', "Ducks R Us");
+        restore_current_blog();
         $site_ids[] = self::createSubDomainSite('duck.example.org', "More Ducks R Us");
+        restore_current_blog();
 
         $post_titles = ["I don't like zebras", "Zebra and a half", "Have a zebra of a time"];
         $others = $this->factory->post->create_many(8);
@@ -154,6 +159,7 @@ public function testPostSearchAcrossSites()
             $this->factory->post->create([
                 'post_title' => array_pop($post_titles),
             ]);
+            restore_current_blog();
         }
 
         $timber_posts = [];