Adds option to replace shortcodes in one string using contents from

another string
Adds unit tests

lib/Cron/Workers/SendingQueue/Tasks/Newsletter.php

@@ -94,7 +94,13 @@ class Newsletter {
     // extract and save newsletter posts
     PostsTask::extractAndSave($rendered_newsletter, $newsletter);
     // update queue with the rendered and pre-processed newsletter
-    $queue->newsletter_rendered_subject = Shortcodes::process($newsletter->subject, $newsletter, null, $queue);
+    $queue->newsletter_rendered_subject = ShortcodesTask::process(
+      $newsletter->subject,
+      $rendered_newsletter['html'],
+      $newsletter,
+      null,
+      $queue
+    );
     $queue->newsletter_rendered_body = $rendered_newsletter;
     $queue->save();
     // catch DB errors
@@ -123,6 +129,7 @@ class Newsletter {
     );
     $prepared_newsletter = ShortcodesTask::process(
       $prepared_newsletter,
+      null,
       $newsletter,
       $subscriber,
       $queue

lib/Cron/Workers/SendingQueue/Tasks/Shortcodes.php

@@ -1,4 +1,5 @@
 <?php
+
 namespace MailPoet\Cron\Workers\SendingQueue\Tasks;
 
 use MailPoet\Newsletter\Shortcodes\Shortcodes as NewsletterShortcodes;
@@ -6,8 +7,8 @@ use MailPoet\Newsletter\Shortcodes\Shortcodes as NewsletterShortcodes;
 if(!defined('ABSPATH')) exit;
 
 class Shortcodes {
-  static function process($content, $newsletter, $subscriber, $queue) {
+  static function process($content, $content_source = null, $newsletter = null, $subscriber = null, $queue = null) {
     $shortcodes = new NewsletterShortcodes($newsletter, $subscriber, $queue);
-    return $shortcodes->replace($content);
+    return $shortcodes->replace($content, $content_source);
   }
 }

lib/Newsletter/Shortcodes/Shortcodes.php

@@ -91,12 +91,18 @@ class Shortcodes {
     return $processed_shortcodes;
   }
 
-  function replace($content, $categories = false) {
+  function replace($content, $content_source = null, $categories = null) {
     $shortcodes = $this->extract($content, $categories);
     if(!$shortcodes) {
       return $content;
     }
-    $processed_shortcodes = $this->process($shortcodes, $content);
+    // if content contains only shortcodes (e.g., [newsletter:post_title]) but their processing
+    // depends on some other content (e.g., "post_id" inside a rendered newsletter),
+    // then we should use that content source when processing shortcodes
+    $processed_shortcodes = $this->process(
+      $shortcodes,
+      ($content_source) ? $content_source : $content
+    );
     $shortcodes = array_intersect_key($shortcodes, $processed_shortcodes);
     return str_replace($shortcodes, $processed_shortcodes, $content);
   }

tests/unit/Cron/Workers/SendingQueue/Tasks/ShortcodesTest.php

@@ -1,4 +1,5 @@
 <?php
+
 namespace MailPoet\Test\Cron\Workers\SendingQueue\Tasks;
 
 use MailPoet\Cron\Workers\SendingQueue\Tasks\Shortcodes;
@@ -8,6 +9,16 @@ use MailPoet\Models\SendingQueue;
 if(!defined('ABSPATH')) exit;
 
 class ShortcodesTest extends \MailPoetTest {
+  function _before() {
+    $this->WP_post = wp_insert_post(
+      array(
+        'post_title' => 'Sample Post',
+        'post_content' => 'contents',
+        'post_status' => 'publish',
+      )
+    );
+  }
+
   function testItCanReplaceShortcodes() {
     $queue = $newsletter = (object)array(
       'id' => 1
@@ -18,12 +29,26 @@ class ShortcodesTest extends \MailPoetTest {
       'last_name' => 'Doe'
     );
     $rendered_body = '[subscriber:firstname] [subscriber:lastname]';
-    $result = Shortcodes::process($rendered_body, $newsletter, $subscriber, $queue);
+    $result = Shortcodes::process($rendered_body, null, $newsletter, $subscriber, $queue);
     expect($result)->equals('John Doe');
   }
 
+  function testItCanReplaceShortcodesInOneStringUsingContentsFromAnother() {
+    $wp_post = get_post($this->WP_post);
+    $content = 'Subject line with one shortcode: [newsletter:post_title]';
+    $content_source = '<a data-post-id="' . $this->WP_post . '" href="#">latest post</a>';
+
+    // [newsletter:post_title] depends on the "data-post-id" tag and the shortcode will
+    // get replaced with an empty string if that tag is not found
+    expect(trim(Shortcodes::process($content)))->equals('Subject line with one shortcode:');
+
+    // when tag is found, the shortcode will be processed and replaced
+    expect(Shortcodes::process($content, $content_source))->equals('Subject line with one shortcode: ' . $wp_post->post_title);
+  }
+
   function _after() {
     \ORM::raw_execute('TRUNCATE ' . SendingQueue::$_table);
     \ORM::raw_execute('TRUNCATE ' . Newsletter::$_table);
+    wp_delete_post($this->WP_post, true);
   }
 }