Use cache_accesor for organization permissions related methods

app/models/user.rb

@@ -245,7 +245,7 @@ def age
   end
 
   def current_organic_context
-    Organization.current? ?  Organization.current : main_organization
+    Organization.safe_current || main_organization
   end
 
   def current_immersive_context_at(path_item)

lib/mumuki/domain/helpers/user.rb

@@ -77,8 +77,11 @@ def to_s
 
   ## Accessible organizations
 
-  revamp_accessor :any_granted_organizations, :student_granted_organizations do |_, _, result|
-    result.map { |org| Mumukit::Platform::Organization.find_by_name!(org) rescue nil }.compact
+  revamp :any_granted_organizations, :student_granted_organizations, selector_transformer: proc { |it| "@__#{it}__".to_sym } do |attr_name, this, hyper|
+    this.instance_variable_get(attr_name) ||
+      hyper.call.map { |org| Mumukit::Platform::Organization.find_by_name!(org) rescue nil }.compact.tap do |organizations|
+        this.instance_variable_set(attr_name, organizations)
+      end
   end
 
   def has_student_granted_organizations?

spec/lib/user_helpers_spec.rb

@@ -162,5 +162,26 @@
         before { organization.settings.immersive = true }
       end
     end
+
+    context 'is memoized properly' do
+      let(:user) { create(:user) }
+
+      before { organization.switch! }
+      before { user.make_student_of!(organization); user.save! }
+      before { expect(Mumukit::Platform.organization_class).to receive(:find_by_name!).with('foo').exactly(1).times.and_return(organization) }
+
+      it { expect(user.student_granted_organizations.size).to eq 1 }
+      it { expect(user.student_granted_organizations).to eq [organization] }
+    end
+
+    context 'memoization may cause issues with uncontextualized users' do
+      let(:user) { create(:user) }
+
+      before { user.make_student_of!(organization); user.save! }
+      before { expect(Mumukit::Platform.organization_class).to receive(:find_by_name!).with('foo').exactly(1).times.and_return(organization) }
+
+      it { expect(user.student_granted_organizations.size).to eq 1 }
+      it { expect(user.student_granted_organizations).to eq [organization] }
+    end
   end
 end