UX: Remove flash of 🌐 when the post has yet to have its language determined (#229)

When a post is just created, we see the 🌐 appear for a brief moment, then disappear.

We typically want to show the 🌐 in case the post is not in the same language as the reader's. This works really well for old posts that do not have translation information. But since now all posts will be sent for locale detection on-create, it is a matter of seconds that the post's locale is determined.

This commit adds a buffer of 10 seconds that will prevent the 🌐 from appearing if 1. it was just created and 2. it doesn't have the locale yet.

Author: nattsw

lib/discourse_translator/dual_text_translation.rb

@@ -15,7 +15,8 @@ def inject(plugin)
       end
 
       plugin.on(:topic_created) do |topic|
-        if SiteSetting.automatic_translation_target_languages.blank? && topic.user_id > 0
+        if SiteSetting.automatic_translation_target_languages.blank? &&
+             Guardian.new.can_detect_language?(topic.first_post) && topic.user_id > 0
           Jobs.enqueue(:detect_translatable_language, type: "Topic", translatable_id: topic.id)
         end
       end

lib/discourse_translator/guardian_extension.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 module DiscourseTranslator::GuardianExtension
+  POST_DETECTION_BUFFER = 10.seconds
+
   def user_group_allow_translate?
     return false if !current_user
     current_user.in_any_groups?(SiteSetting.restrict_translation_by_group_map)
@@ -24,6 +26,10 @@ def can_translate?(post)
     return false if !user_group_allow_translate?
     return false if post.locale_matches?(I18n.locale)
 
+    # we want to return false if the post is created within a short buffer ago,
+    # this prevents the 🌐from appearing and then disappearing if the lang is same as user's lang
+    return false if post.created_at > POST_DETECTION_BUFFER.ago && post.detected_locale.blank?
+
     if SiteSetting.experimental_topic_translation
       post.translation_for(I18n.locale).nil?
     else

spec/lib/guardian_extension_spec.rb

@@ -117,7 +117,7 @@
   describe "#can_translate?" do
     fab!(:group)
     fab!(:user) { Fabricate(:user, locale: "en", groups: [group]) }
-    fab!(:post)
+    fab!(:post) { Fabricate(:post, created_at: 5.minutes.ago) }
 
     let(:guardian) { Guardian.new(user) }
 
@@ -127,7 +127,7 @@
       expect(guardian.can_translate?(post)).to eq(false)
     end
 
-    describe "when translator enabled" do
+    describe "when translator enabled and user locale is pt" do
       before do
         SiteSetting.translator_enabled = true
         I18n.locale = :pt
@@ -160,6 +160,22 @@
         expect(guardian.can_translate?(post)).to eq(false)
       end
 
+      it "allows translation depending on when the post is created" do
+        SiteSetting.restrict_translation_by_group = "#{group.id}"
+
+        post.update(created_at: Time.now)
+        expect(guardian.can_translate?(post)).to eq(false)
+
+        post.set_detected_locale("jp")
+        expect(guardian.can_translate?(post)).to eq(true)
+
+        post.update(created_at: 5.minutes.ago)
+        expect(guardian.can_translate?(post)).to eq(true)
+
+        post.set_detected_locale("pt")
+        expect(guardian.can_translate?(post)).to eq(false)
+      end
+
       describe "when experimental_topic_translation enabled" do
         before { SiteSetting.experimental_topic_translation = true }
 

spec/models/post_spec.rb

@@ -70,13 +70,20 @@
 
   describe "queueing post for language detection" do
     fab!(:group)
-    fab!(:topic)
     fab!(:user) { Fabricate(:user, groups: [group]) }
 
     it "queues the post for language detection when user and posts are in the right group" do
       SiteSetting.restrict_translation_by_poster_group = "#{group.id}"
 
-      post = Fabricate(:post, user: user)
+      post =
+        PostCreator.new(
+          user,
+          {
+            title: "a topic about cats",
+            raw: "tomtom is a cat",
+            category: Fabricate(:category).id,
+          },
+        ).create
       CookedPostProcessor.new(post).post_process
 
       expect_job_enqueued(
@@ -86,6 +93,13 @@
           translatable_id: post.id,
         },
       )
+      expect_job_enqueued(
+        job: :detect_translatable_language,
+        args: {
+          type: "Topic",
+          translatable_id: post.topic_id,
+        },
+      )
     end
 
     it "does not queue bot posts for language detection" do