From b27bcdd42b464a9338f457b5c28ff2dbf890ad55 Mon Sep 17 00:00:00 2001
From: Eileen McNaughton <emcnaughton@wikimedia.org>
Date: Thu, 12 Jan 2023 17:42:00 +1300
Subject: [PATCH] Ensure useful exception thrown for all Smarty errors from
 user strings

---
 CRM/Core/Smarty.php                    | 18 ++++++++++++++++++
 CRM/Utils/String.php                   |  8 +++++++-
 tests/phpunit/CRM/Utils/StringTest.php | 14 ++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/CRM/Core/Smarty.php b/CRM/Core/Smarty.php
index 4874e2b542..5c0d1d884a 100644
--- a/CRM/Core/Smarty.php
+++ b/CRM/Core/Smarty.php
@@ -19,6 +19,9 @@
  * Fix for bug CRM-392. Not sure if this is the best fix or it will impact
  * other similar PEAR packages. doubt it
  */
+
+use Civi\Core\Event\SmartyErrorEvent;
+
 if (!class_exists('Smarty')) {
   require_once 'Smarty/Smarty.class.php';
 }
@@ -196,6 +199,21 @@ class CRM_Core_Smarty extends Smarty {
     return $output;
   }
 
+  /**
+   * Handle smarty error in one off string.
+   *
+   * @param int $errorNumber
+   * @param string $errorMessage
+   *
+   * @throws \CRM_Core_Exception
+   */
+  public function handleSmartyError(int $errorNumber, string $errorMessage): void {
+    $event = new SmartyErrorEvent($errorNumber, $errorMessage);
+    \Civi::dispatcher()->dispatch('civi.smarty.error', $event);
+    restore_error_handler();
+    throw new \CRM_Core_Exception('Message was not parsed due to invalid smarty syntax : ' . $errorMessage);
+  }
+
   /**
    * Ensure these variables are set to make it easier to access them without e-notice.
    *
diff --git a/CRM/Utils/String.php b/CRM/Utils/String.php
index e654e862a7..69f74151a0 100644
--- a/CRM/Utils/String.php
+++ b/CRM/Utils/String.php
@@ -1026,6 +1026,10 @@ class CRM_Utils_String {
    * @param string $templateString
    *
    * @return string
+   *
+   * @noinspection PhpDocRedundantThrowsInspection
+   *
+   * @throws \CRM_Core_Exception
    */
   public static function parseOneOffStringThroughSmarty($templateString) {
     if (!CRM_Utils_String::stringContainsTokens($templateString)) {
@@ -1034,13 +1038,15 @@ class CRM_Utils_String {
     }
     $smarty = CRM_Core_Smarty::singleton();
     $cachingValue = $smarty->caching;
+    set_error_handler([$smarty, 'handleSmartyError'], E_USER_ERROR);
     $smarty->caching = 0;
     $smarty->assign('smartySingleUseString', $templateString);
     // Do not escape the smartySingleUseString as that is our smarty template
     // and is likely to contain html.
     $templateString = (string) $smarty->fetch('string:{eval var=$smartySingleUseString|smarty:nodefaults}');
     $smarty->caching = $cachingValue;
-    $smarty->assign('smartySingleUseString', NULL);
+    $smarty->assign('smartySingleUseString');
+    restore_error_handler();
     return $templateString;
   }
 
diff --git a/tests/phpunit/CRM/Utils/StringTest.php b/tests/phpunit/CRM/Utils/StringTest.php
index 1e4cfdf5b8..43850aaa48 100644
--- a/tests/phpunit/CRM/Utils/StringTest.php
+++ b/tests/phpunit/CRM/Utils/StringTest.php
@@ -442,4 +442,18 @@ class CRM_Utils_StringTest extends CiviUnitTestCase {
     $this->assertFalse(CRM_Utils_String::unserialize($str));
   }
 
+  /**
+   * Test that we get a meaningful error if Smarty syntax is wrong.
+   */
+  public function testSmartyExceptionHandling(): void {
+    try {
+      CRM_Utils_String::parseOneOffStringThroughSmarty('{if}');
+    }
+    catch (CRM_Core_Exception $e) {
+      $this->assertStringStartsWith('Message was not parsed due to invalid smarty syntax', $e->getMessage());
+      return;
+    }
+    $this->fail('Exception expected');
+  }
+
 }
-- 
2.25.1