validate a PR after every PR update / prevent loops

This change will trigger a sidekiq job after every update on a PR. With
two exceptions: If eligible_for_merge_comment or eligible_for_ci_comment
got updated, we won't triger a job. Those attribute are *only* set in
the validation methods.

.rubocop_todo.yml

@@ -1,15 +1,15 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2020-05-07 22:11:39 +0200 using RuboCop version 0.82.0.
+# on 2020-05-08 14:09:55 +0200 using RuboCop version 0.82.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 13
+# Offense count: 12
 # Configuration parameters: IgnoredMethods.
 Metrics/AbcSize:
-  Max: 42
+  Max: 41
 
 # Offense count: 2
 # Configuration parameters: CountComments, ExcludedMethods.
@@ -20,9 +20,9 @@ Metrics/BlockLength:
 # Offense count: 2
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
-  Max: 123
+  Max: 122
 
-# Offense count: 2
+# Offense count: 1
 # Configuration parameters: IgnoredMethods.
 Metrics/CyclomaticComplexity:
   Max: 7

app/models/pull_request.rb

@@ -160,14 +160,8 @@ def validate(saved_changes)
     # If we're running in development mode, we try to run read-only and won't modify PRs
     return if Rails.env.development?
 
-    # Don't run through the validaten, if only the eligible_for_merge_comment attribute got updated
-    if saved_changes.keys.sort != %w[updated_at eligible_for_merge_comment].sort && mergeable.nil?
-      # check merge status and do work if required
-      validate_mergeable
-    end
-
-    # Don't run through the validaten, if only the eligible_for_ci_comment attribute got updated
-    return unless saved_changes.keys.sort != %w[updated_at eligible_for_ci_comment].sort
+    # check merge status and do work if required
+    validate_mergeable
 
     # check CI status and do work if required
     validate_status(saved_changes)
@@ -176,11 +170,14 @@ def validate(saved_changes)
   private
 
   ##
-  #  Since we want to be a fancy responsive application we to all the validation
-  #  stuff which might result in some new querys and api requests asyncronously.
-
+  # Queue a job into sidekiq that runs the validate() method above
+  # validate() might use update() to change attributes which would trigger a new job
+  # To prevent loops, we filter `saved_changed` of those attributes and won't create new job if those are the only changed attributes
   def queue_validation
-    ValidatePullRequestWorker.perform_async(id, saved_changes) if saved_changes? || mergeable.nil?
+    attributes = %w[eligible_for_merge_comment eligible_for_ci_comment]
+    return unless [saved_changes.keys & attributes].empty?
+
+    ValidatePullRequestWorker.perform_async(id, saved_changes)
   end
 
   def validate_mergeable