Yet another try at fixing #5455

lib/analytics/campaign_csv_builder.rb

@@ -50,7 +50,10 @@ def wikidata_to_csv
     courses = @campaign.courses
                        .joins(:course_stat)
     courses.find_each do |course|
-      csv_data << CourseWikidataCsvBuilder.new(course).stat_row
+      builder = CourseWikidataCsvBuilder.new(course)
+      next unless builder.wikidata_stats?
+
+      csv_data << builder.stat_row
     end
 
     csv_data << sum_wiki_columns(csv_data) if courses.any?
@@ -60,7 +63,7 @@ def wikidata_to_csv
 
   def sum_wiki_columns(csv_data)
     # Skip 1st header row + 1st column course name
-    csv_data[1..].transpose[1..]&.map(&:sum)&.unshift('Total')
+    csv_data[1..].transpose[1..].map(&:sum).unshift('Total')
   end
 
   class AllCourses

lib/analytics/course_wikidata_csv_builder.rb

@@ -14,14 +14,15 @@ def generate_csv
     CSV.generate { |csv| csv_data.each { |line| csv << line } }
   end
 
+  def wikidata_stats?
+    @course.course_stat && @course.course_stat.stats_hash['www.wikidata.org']
+  end
+
   def stat_row
     hash_stats = @course
                  .course_stat.stats_hash['www.wikidata.org']
                  &.merge({ 'course name' => @course.title })
 
-    # this method gets called directly from CampaignCsvBuilder, so we need
-    # to guard for courses that don't have any Wikidata stats.
-    return [] unless hash_stats
     CSV_HEADERS.map { |elmnt| hash_stats.fetch elmnt, 0 }
   end
 
@@ -55,10 +56,4 @@ def stat_row
     'no data',
     'total revisions'
   ].freeze
-
-  private
-
-  def wikidata_stats?
-    @course.course_stat && @course.course_stat.stats_hash['www.wikidata.org']
-  end
 end