readd diff_type to user preferences

app/controllers/repositories_controller.rb

@@ -259,14 +259,7 @@ class RepositoriesController < ApplicationController
                 type: 'text/x-patch',
                 disposition: 'attachment'
     else
-      @diff_type = params[:type] || User.current.pref[:diff_type] || 'inline'
+      @diff_type = diff_type_persisted
-      @diff_type = 'inline' unless %w(inline sbs).include?(@diff_type)
-
-      # Save diff type as user preference
-      if User.current.logged? && @diff_type != User.current.pref[:diff_type]
-        User.current.pref[:diff_type] = @diff_type
-        User.current.preference.save
-      end
 
       @cache_key = "repositories/diff/#{@repository.id}/" +
                    Digest::MD5.hexdigest("#{@path}-#{@rev}-#{@rev_to}-#{@diff_type}")
@@ -497,6 +490,21 @@ class RepositoriesController < ApplicationController
     # rails looking for e.g text when .txt is asked for
     render 'entry', formats: [:html]
   end
+
+  def diff_type_persisted
+    preferences = current_user.pref
+
+    diff_type = params[:type] || preferences.diff_type
+    diff_type = 'inline' unless %w(inline sbs).include?(diff_type)
+
+    # Save diff type as user preference
+    if current_user.logged? && diff_type != preferences.diff_type
+      preferences.diff_type = diff_type
+      preferences.save
+    end
+
+    diff_type
+  end
 end
 
 class Date

app/models/user_preference.rb

@@ -85,6 +85,10 @@ class UserPreference < ApplicationRecord
     comments_sorting == 'desc'
   end
 
+  def diff_type
+    settings.fetch(:diff_type, 'inline')
+  end
+
   def hide_mail
     settings.fetch(:hide_mail, true)
   end

config/schemas/user_preferences.schema.json

@@ -22,6 +22,10 @@
                 "auto_hide_popups": {
                     "type": "boolean"
                 },
+                "diff_type": {
+                  "type": "string",
+                  "enum": ["inline", "sbs"]
+                },
                 "workdays": {
                   "type": "array",
                   "items": {

spec/models/user_preference_spec.rb

@@ -140,6 +140,27 @@ describe UserPreference do
     end
   end
 
+  describe '#diff_type' do
+    it 'can be set and written' do
+      expect(subject.diff_type)
+        .to eql 'inline'
+
+      subject.diff_type = 'sbs'
+
+      expect(subject.diff_type)
+        .to eql 'sbs'
+    end
+
+    context 'with a new pref instance' do
+      subject { described_class.new }
+
+      it 'defaults to `inline`' do
+        expect(subject.diff_type)
+          .to eql 'inline'
+      end
+    end
+  end
+
   describe '#daily_reminders' do
     context 'without reminders being stored' do
       it 'uses the defaults' do