DEV: ensure rebaking works even when some users have inconsistent data (#30261)

* DEV: add db consistency check for UserEmail

* DEV: add db consistency check for UserAvatar

* DEV: ignore inconsistent data related to user avatars when deciding whether to rebake old posts


Co-authored-by: Alan Guo Xiang Tan <gxtan1990@gmail.com>

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Co-authored-by: Alan Guo Xiang Tan <gxtan1990@gmail.com>

app/models/user_avatar.rb

@@ -152,6 +152,13 @@ class UserAvatar < ActiveRecord::Base
   end
 
   def self.ensure_consistency!(max_optimized_avatars_to_remove: 20_000)
+    DB.exec <<~SQL
+      DELETE FROM user_avatars
+      USING user_avatars ua
+      LEFT JOIN users u ON ua.user_id = u.id
+      WHERE user_avatars.id = ua.id AND u.id IS NULL
+    SQL
+
     DB.exec <<~SQL
       UPDATE user_avatars
       SET gravatar_upload_id = NULL

app/models/user_email.rb

@@ -22,6 +22,23 @@ class UserEmail < ActiveRecord::Base
   before_save -> { destroy_email_tokens(self.email_was) }, if: :will_save_change_to_email?
 
   after_destroy { destroy_email_tokens(self.email) }
+  def self.ensure_consistency!
+    user_ids_without_primary_email = DB.query_single <<~SQL
+      SELECT u.id
+      FROM users u
+      LEFT JOIN user_emails ue ON u.id = ue.user_id AND ue.primary = true
+      WHERE ue.id IS NULL;
+    SQL
+
+    user_ids_without_primary_email.each do |user_id|
+      UserEmail.create!(
+        user_id: user_id,
+        # 64 max character length of local-part for the email address https://datatracker.ietf.org/doc/html/rfc5321#section-4.5.3.1.1
+        email: "#{SecureRandom.alphanumeric(64)}@missing-primary-email.invalid",
+        primary: true,
+      )
+    end
+  end
 
   def normalize_email
     self.normalized_email =