From 630613db7528b070fd431a56a2da5ca86d2cd5e3 Mon Sep 17 00:00:00 2001
From: greg84 <gregslater@gmx.com>
Date: Thu, 14 Sep 2017 20:29:54 +0100
Subject: [PATCH] Only query database if a new tag is being added. (#7845)

---
 .../Modules/Orchard.Tags/Services/TagService.cs    | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/Orchard.Web/Modules/Orchard.Tags/Services/TagService.cs b/src/Orchard.Web/Modules/Orchard.Tags/Services/TagService.cs
index bd50820bd..662f0efb4 100644
--- a/src/Orchard.Web/Modules/Orchard.Tags/Services/TagService.cs
+++ b/src/Orchard.Web/Modules/Orchard.Tags/Services/TagService.cs
@@ -191,20 +191,22 @@ namespace Orchard.Tags.Services {
         }
 
         public void UpdateTagsForContentItem(ContentItem contentItem, IEnumerable<string> tagNamesForContentItem) {
-            var tags = tagNamesForContentItem.Select(CreateTag);
-            var newTagsForContentItem = new List<TagRecord>(tags);
+            var newTagsForContentItem = tagNamesForContentItem.Where(s => s != null).ToList();
             var currentTagsForContentItem = contentItem.As<TagsPart>().Record.Tags;
 
             foreach (var tagContentItem in currentTagsForContentItem) {
-                if (!newTagsForContentItem.Contains(tagContentItem.TagRecord)) {
+                var newTag = newTagsForContentItem.FirstOrDefault(t => t.Equals(tagContentItem.TagRecord.TagName, StringComparison.OrdinalIgnoreCase));
+
+                if (newTag == null) {
                     _contentTagRepository.Delete(tagContentItem);
                 }
-
-                newTagsForContentItem.Remove(tagContentItem.TagRecord);
+                else {
+                    newTagsForContentItem.Remove(newTag);
+                }
             }
 
             foreach (var newTagForContentItem in newTagsForContentItem) {
-                _contentTagRepository.Create(new ContentTagRecord { TagsPartRecord = contentItem.As<TagsPart>().Record, TagRecord = newTagForContentItem });
+                _contentTagRepository.Create(new ContentTagRecord { TagsPartRecord = contentItem.As<TagsPart>().Record, TagRecord = CreateTag(newTagForContentItem) });
             }
 
             contentItem.As<TagsPart>().CurrentTags = tagNamesForContentItem;