Add escaping for known shortcodes when rendered in form textarea's value

[MAILPOET-5243]

mailpoet/lib/Form/Block/BlockRendererHelper.php

@@ -258,6 +258,15 @@ class BlockRendererHelper {
     return join(' ', $modifiers);
   }
 
+  public function escapeShortCodes(?string $value): ?string {
+    if ($value === null) {
+      return null;
+    }
+    return preg_replace_callback('/' . $this->wp->getShortcodeRegex() . '/s', function ($matches) {
+      return str_replace(['[', ']'], ['[', ']'], $matches[0]);
+    }, $value);
+  }
+
   private function translateValidationErrorMessage(string $validate): string {
     switch ($validate) {
       case 'email':

mailpoet/lib/Form/Block/Textarea.php

@@ -55,7 +55,7 @@ class Textarea {
       $html .= 'style="' . $this->wp->escAttr($styles) . '" ';
     }
 
-    $html .= '>' . $this->rendererHelper->getFieldValue($block) . '</textarea>';
+    $html .= '>' . $this->rendererHelper->escapeShortCodes($this->rendererHelper->getFieldValue($block)) . '</textarea>';
 
     return $this->wrapper->render($block, $html);
   }

mailpoet/lib/WP/Functions.php

@@ -881,4 +881,8 @@ class Functions {
 
     return false;
   }
+
+  public function getShortcodeRegex($tagnames = null): string {
+    return get_shortcode_regex($tagnames);
+  }
 }

mailpoet/tests/integration/Form/Block/BlockRendererHelperTest.php

@@ -0,0 +1,16 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Form\Block;
+
+/**
+ * There is also a unit test for this class in mailpoet/tests/unit/Form/Block/BlockRendererHelperTest.php
+ * The integration test method that need WordPress to be loaded.
+ */
+class BlockRendererHelperTest extends \MailPoetTest {
+  public function testItEscapesKnownShortCodes() {
+    $text = '[mailpoet_subscribers_count] [gallery attr="attr"]inside[/gallery][unknown]';
+    $rendererHelper = $this->diContainer->get(BlockRendererHelper::class);
+    $escaped = $rendererHelper->escapeShortCodes($text);
+    expect($escaped)->equals('&#91;mailpoet_subscribers_count&#93; &#91;gallery attr="attr"&#93;inside&#91;/gallery&#93;[unknown]');
+  }
+}

mailpoet/tests/unit/Form/Block/TextareaTest.php

@@ -62,6 +62,7 @@ class TextareaTest extends \MailPoetUnitTest {
     $this->rendererHelperMock->expects($this->once())->method('getInputValidation')->willReturn(' validation="1" ');
     $this->rendererHelperMock->expects($this->once())->method('getInputModifiers')->willReturn(' modifiers="mod" ');
     $this->rendererHelperMock->expects($this->once())->method('getFieldValue')->willReturn('val');
+    $this->rendererHelperMock->expects($this->once())->method('escapeShortCodes')->will($this->returnArgument(0));
     $this->stylesRendererMock->expects($this->once())->method('renderForTextInput')->willReturn('border-radius: 10px;');
 
     $html = $this->textarea->render($this->block, []);