FIX: mentions regex server-side (ie. don't count email addresses)

app/models/post_analyzer.rb

@@ -52,8 +52,11 @@ class PostAnalyzer
     cooked_stripped.css("code").remove
     cooked_stripped.css(".onebox").remove
 
-    results = cooked_stripped.to_html.scan(PrettyText.mention_matcher)
-    @raw_mentions = results.uniq.map { |un| un.first.downcase.sub!(/^@/, '') }
+    @raw_mentions = cooked_stripped.to_html
+                                   .scan(PrettyText.mention_matcher)
+                                   .flatten
+                                   .map(&:downcase)
+                                   .uniq
   end
 
   # from rack ... compat with ruby 2.2

lib/pretty_text.rb

@@ -74,7 +74,7 @@ module PrettyText
   @ctx_init = Mutex.new
 
   def self.mention_matcher
-    Regexp.new("(\@[a-zA-Z0-9_]{#{User.username_length.begin},#{User.username_length.end}})")
+    Regexp.new("\\W@(\\w{#{SiteSetting.min_username_length},#{SiteSetting.max_username_length}})\\b")
   end
 
   def self.app_root

spec/models/post_analyzer_spec.rb

@@ -205,5 +205,10 @@ describe PostAnalyzer do
       post_analyzer = PostAnalyzer.new("@Jake @Finn @Jake_Old", default_topic_id)
       expect(post_analyzer.raw_mentions).to eq(['jake', 'finn', 'jake_old'])
     end
+
+    it "ignores emails" do
+      post_analyzer = PostAnalyzer.new("1@test.com 1@best.com @best @not", default_topic_id)
+      expect(post_analyzer.raw_mentions).to eq(['best', 'not'])
+    end
   end
 end