FIX: Don't migrate custom emojis that are no longer valid.

* Warn about failed migration in logs.

app/jobs/onceoff/migrate_custom_emojis.rb

@@ -3,33 +3,39 @@ module Jobs
     def execute_onceoff(args)
       return if Rails.env.test?
 
-      CustomEmoji.transaction do
-        Dir["#{Rails.root}/#{Emoji.base_directory}/*.{png,gif}"].each do |path|
-          name = File.basename(path, File.extname(path))
+      Dir["#{Rails.root}/#{Emoji.base_directory}/*.{png,gif}"].each do |path|
+        name = File.basename(path, File.extname(path))
 
-          File.open(path) do |file|
-            upload = Upload.create_for(
-              Discourse.system_user.id,
-              file,
-              File.basename(path),
-              file.size,
-              image_type: 'custom_emoji'
-            )
+        File.open(path) do |file|
+          upload = Upload.create_for(
+            Discourse.system_user.id,
+            file,
+            File.basename(path),
+            file.size,
+            image_type: 'custom_emoji'
+          )
 
-            if upload.persisted?
-              CustomEmoji.create!(name: name, upload: upload)
-            else
-              raise "Failed to create upload for '#{name}' custom emoji"
+          if upload.persisted?
+            custom_emoji = CustomEmoji.new(name: name, upload: upload)
+
+            if !custom_emoji.save
+              warn("Failed to create custom emoji '#{name}': #{custom_emoji.errors.full_messages}")
             end
+          else
+            warn("Failed to create upload for '#{name}' custom emoji: #{upload.errors.full_messages}")
           end
         end
-
-        Emoji.clear_cache
-
-        Post.where("cooked LIKE '%#{Emoji.base_url}%'").find_each do |post|
-          post.rebake!
-        end
       end
+
+      Emoji.clear_cache
+
+      Post.where("cooked LIKE '%#{Emoji.base_url}%'").find_each do |post|
+        post.rebake!
+      end
+    end
+
+    def warn(message)
+      Rails.logger.warn(message)
     end
   end
 end