FIX: don't send digests to users with no primary email

It might happen that some User records have no associated primary emails.
In which case we don't ever want to send them a digest.

Also added a new "user_email_no_email" skipped email log to ensure these cases
are properly handled and surfaced.

app/jobs/regular/user_email.rb

@@ -26,16 +26,17 @@ module Jobs
       notification = nil
       type = args[:type]
       user = User.find_by(id: args[:user_id])
-      to_address = args[:to_address].presence || user.try(:email).presence || "no_email_found"
+      to_address = args[:to_address].presence || user&.primary_email&.email.presence || "no_email_found"
 
       set_skip_context(type, args[:user_id], to_address, args[:post_id])
 
-      return skip(SkippedEmailLog.reason_types[:user_email_no_user]) unless user
+      return skip(SkippedEmailLog.reason_types[:user_email_no_user]) if !user
+      return skip(SkippedEmailLog.reason_types[:user_email_no_email]) if to_address == "no_email_found"
 
       if args[:post_id].present?
         post = Post.find_by(id: args[:post_id])
 
-        unless post.present?
+        if post.blank?
           return skip(SkippedEmailLog.reason_types[:user_email_post_not_found])
         end
 

app/jobs/scheduled/enqueue_digest_emails.rb

@@ -14,13 +14,15 @@ module Jobs
 
     def target_user_ids
       # Users who want to receive digest email within their chosen digest email frequency
-      query = User.real
-        .not_suspended
+      query = User
+        .real
         .activated
+        .not_suspended
         .where(staged: false)
-        .joins(:user_option, :user_stat)
+        .joins(:user_option, :user_stat, :user_emails)
         .where("user_options.email_digests")
         .where("user_stats.bounce_score < #{SiteSetting.bounce_score_threshold}")
+        .where("user_emails.primary")
         .where("COALESCE(last_emailed_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 MINUTE'::INTERVAL * user_options.digest_after_minutes)")
         .where("COALESCE(last_seen_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 MINUTE'::INTERVAL * user_options.digest_after_minutes)")
         .where("COALESCE(last_seen_at, '2010-01-01') >= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * #{SiteSetting.suppress_digest_email_after_days})")

app/models/skipped_email_log.rb

@@ -37,7 +37,8 @@ class SkippedEmailLog < ActiveRecord::Base
       sender_post_deleted: 20,
       sender_message_to_invalid: 21,
       user_email_access_denied: 22,
-      sender_topic_deleted: 23
+      sender_topic_deleted: 23,
+      user_email_no_email: 24,
       # you need to add the reason in server.en.yml below the "skipped_email_log" key
       # when you add a new enum value
     )

config/locales/server.en.yml

@@ -3803,6 +3803,7 @@ en:
     user_email_user_suspended: "user was suspended"
     user_email_already_read: "user has already read this post"
     user_email_access_denied: "user is not allowed to see this post"
+    user_email_no_email: "No email associated with user id %{user_id}"
     sender_message_blank: "message is blank"
     sender_message_to_blank: "message.to is blank"
     sender_text_part_body_blank: "text_part.body is blank"

spec/jobs/enqueue_digest_emails_spec.rb

@@ -107,6 +107,14 @@ describe Jobs::EnqueueDigestEmails do
       end
     end
 
+    context "no primary email" do
+      let!(:user) { Fabricate(:active_user, last_seen_at: 2.months.ago) }
+
+      it "doesn't return users with no primary emails" do
+        UserEmail.where(user: user).delete_all
+        expect(Jobs::EnqueueDigestEmails.new.target_user_ids.include?(user.id)).to eq(false)
+      end
+    end
   end
 
   describe '#execute' do