From dce3931f20822850d40851c2a87fddda3984fa70 Mon Sep 17 00:00:00 2001
From: Ben Thomson <git@alfreido.com>
Date: Mon, 31 Aug 2020 14:18:53 +0800
Subject: [PATCH] Clean up uncustomised partials if they are no longer
 provided.

An exception was being thrown in some instances if a partial had been added to the DB that was provided by a plugin that no longer exists, or had been disabled. This will remove any partials provided by non-existent plugins, only if they haven't been subsequently customised by the developer.

Fixes https://github.com/octobercms/october/issues/5065
---
 modules/system/models/MailPartial.php | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/modules/system/models/MailPartial.php b/modules/system/models/MailPartial.php
index ac1971690..5d003fcf0 100644
--- a/modules/system/models/MailPartial.php
+++ b/modules/system/models/MailPartial.php
@@ -72,14 +72,24 @@ class MailPartial extends Model
      */
     public static function createPartials()
     {
-        $dbPartials = self::lists('code', 'code');
+        $partials = MailManager::instance()->listRegisteredPartials();
+        $dbPartials = self::lists('is_custom', 'code');
+        $newPartials = array_diff_key($partials, $dbPartials);
 
-        $definitions = MailManager::instance()->listRegisteredPartials();
-        foreach ($definitions as $code => $path) {
-            if (array_key_exists($code, $dbPartials)) {
+        /*
+         * Clean up non-customized partials
+         */
+        foreach ($dbPartials as $code => $isCustom) {
+            if ($isCustom) {
                 continue;
             }
 
+            if (!array_key_exists($code, $partials)) {
+                self::whereCode($code)->delete();
+            }
+        }
+
+        foreach ($newPartials as $code => $path) {
             $partial = new static;
             $partial->code = $code;
             $partial->is_custom = 0;