FIX: No longer educate users who are editing

A user editing a post will no longer get composer messages that are
meant for new users posting replies and threads. These messages don't
make sense in an edit context at all -- they're usually discussing
making salient replies or topics, or adding avatars. They make even less
sense when a user is an admin attempting to change the default topics
for the first time.

Since these messages actually do make sense for a user when they have a
low post count, though, they're still going to occur. They just occur
when a user is creating new content (and thus, more likely to read the
notice), not during edits.

This is in response to this issue:
https://meta.discourse.org/t/education-message-for-editing-wiki-topic/66682

lib/composer_messages_finder.rb

@@ -11,10 +11,13 @@ class ComposerMessagesFinder
   end
 
   def find
+    return if editing_post?
+
     self.class.check_methods.each do |m|
       msg = send(m)
       return msg if msg.present?
     end
+
     nil
   end
 
@@ -210,4 +213,8 @@ class ComposerMessagesFinder
     @details[:composer_action] == "reply"
   end
 
+  def editing_post?
+    @details[:composer_action] == "edit"
+  end
+
 end

spec/components/composer_messages_finder_spec.rb

@@ -467,4 +467,31 @@ describe ComposerMessagesFinder do
     end
   end
 
+  context 'when editing a post' do
+    let(:user) { Fabricate(:user) }
+    let(:topic) { Fabricate(:post).topic }
+
+    let!(:post) do
+      post = PostCreator.create!(
+        user,
+        topic_id: topic.id,
+        post_number: 1,
+        raw: 'omg my first post'
+      )
+    end
+
+    let(:edit_post_finder) do
+      ComposerMessagesFinder.new(user, composer_action: 'edit')
+    end
+
+    before do
+      SiteSetting.disable_avatar_education_message = true
+      SiteSetting.educate_until_posts = 2
+    end
+
+    it "returns nothing even if it normally would" do
+      expect(edit_post_finder.find).to eq(nil)
+    end
+  end
+
 end