1 files changed, 37 insertions, 0 deletions

diff --git a/lib/tasks/tags.rake b/lib/tasks/tags.rake
new file mode 100644
index 00000000..7521c2f9
--- /dev/null
+++ b/lib/tasks/tags.rake
@@ -0,0 +1,37 @@
+namespace :tags do
+  desc "Merge tags differing only in case into one lowercase tag and " \
+       "lowercase every remaining name. Idempotent; safe to re-run."
+  task :merge_case_duplicates => :environment do
+    merged = renamed = 0
+
+    ActiveRecord::Base.transaction do
+      ActsAsTaggableOn::Tag.pluck(Arel.sql("DISTINCT LOWER(name)")).each do |lower|
+        group  = ActsAsTaggableOn::Tag.where("LOWER(name) = ?", lower).order(:id).to_a
+        keeper = group.find { |t| t.name == lower } || group.first
+
+        (group - [keeper]).each do |dup|
+          dup.taggings.find_each do |tagging|
+            duplicate = ActsAsTaggableOn::Tagging.where(
+              :tag_id => keeper.id,
+              :taggable_type => tagging.taggable_type,
+              :taggable_id   => tagging.taggable_id,
+              :context       => tagging.context,
+              :tagger_type   => tagging.tagger_type,
+              :tagger_id     => tagging.tagger_id).exists?
+            duplicate ? tagging.destroy : tagging.update!(:tag_id => keeper.id)
+          end
+          dup.reload.destroy!
+          merged += 1
+        end
+
+        if keeper.name != lower
+          keeper.update!(:name => lower)
+          renamed += 1
+        end
+        ActsAsTaggableOn::Tag.reset_counters(keeper.id, :taggings)
+      end
+    end
+
+    puts "Merged #{merged} duplicate tags, lowercased #{renamed} names"
+  end
+end