Fixes language switching to default language

Closes #2632

From this commit on the language id won't be stored in the session any more.

Upon every page visit the language id got stored in the session. When switching from a secondary language to the default language no language param is passed to the controller. The order how the language is found prioritized the session and the default was just a fallback. Coming from a secondary language and therefore it's id in the session, it would never load the default language, but the secondary.

Storing the language in the session was most likely a performance optimization. Removing this should not impact current behaviour.

lib/alchemy/controller_actions.rb

@@ -59,17 +59,15 @@ def set_current_alchemy_site
       Site.current = current_alchemy_site
     end
 
-    # Try to find and stores current language for Alchemy.
+    # Sets the current language for Alchemy.
     #
     def set_alchemy_language(lang = nil)
       @language = if lang
         lang.is_a?(Language) ? lang : load_alchemy_language_from_id_or_code(lang)
       else
-        # find the best language and remember it for later
-        load_alchemy_language_from_params ||
-          load_alchemy_language_from_session ||
-          Language.default
+        load_alchemy_language_from_params || Language.default
       end
+
       store_current_alchemy_language(@language)
     end
 
@@ -80,26 +78,15 @@ def load_alchemy_language_from_params
       end
     end
 
-    # Load language from session if it's present on current site.
-    # Otherwise return nil so we can load the default language from current site.
-    def load_alchemy_language_from_session
-      if session[:alchemy_language_id].present? && Site.current
-        Site.current.languages.find_by(id: session[:alchemy_language_id])
-      end
-    end
-
     def load_alchemy_language_from_id_or_code(id_or_code)
       Language.find_by(id: id_or_code) ||
         Language.find_by_code(id_or_code)
     end
 
-    # Stores language's id in the session.
-    #
-    # Also stores language in +Language.current+
+    # Stores language in +Language.current+
     #
     def store_current_alchemy_language(language)
       if language&.id
-        session[:alchemy_language_id] = language.id
         Language.current = language
       end
     end

spec/controllers/alchemy/admin/languages_controller_spec.rb

@@ -128,11 +128,6 @@
 
     let(:language) { create(:alchemy_language, :klingon) }
 
-    it "should store the current language in session" do
-      switch
-      expect(session[:alchemy_language_id]).to eq(language.id)
-    end
-
     context "having a referer" do
       before do
         expect_any_instance_of(ActionDispatch::Request).to receive(:referer) do

spec/controllers/alchemy/pages_controller_spec.rb

@@ -213,11 +213,6 @@ module Alchemy
           end
 
           context "with no lang parameter present" do
-            it "should store defaults language id in the session." do
-              get :show, params: {urlname: page.urlname}
-              expect(controller.session[:alchemy_language_id]).to eq(Language.default.id)
-            end
-
             it "should store default language as class var." do
               get :show, params: {urlname: page.urlname}
               expect(Language.current).to eq(Language.default)

spec/helpers/alchemy/base_helper_spec.rb

@@ -84,7 +84,6 @@ module Alchemy
 
         context "of an existing page" do
           it "should return the page object" do
-            session[:alchemy_language_id] = page.language_id
             expect(helper.page_or_find(page.page_layout)).to eq(page)
           end
         end