Fix #4491: Have tag rename option for bulk update requests.

* Add a `rename A -> B` command for bulk update requests.
* Change mass updates to only retag the posts, not to move saved
  searches or blacklists.

A tag rename does the same thing an alias does, except it doesn't
create a permanent alias. More precisely, a tag rename:

* Moves the wiki.
* Moves the artist entry.
* Moves saved searches.
* Moves blacklists.
* Merges the wikis, if both tags have wiki pages.
* Merges the artist entries, if both tags have artist pages.
* Fixes links in wiki pages to point to the new tag.
* Retags the posts.

test/jobs/tag_batch_change_job_test.rb

@@ -8,42 +8,13 @@ class TagBatchChangeJobTest < ActiveJob::TestCase
     end
 
     should "execute" do
-      TagBatchChangeJob.perform_now("aaa", "bbb", @user, "127.0.0.1")
+      TagBatchChangeJob.perform_now("aaa", "bbb")
       assert_equal("bbb", @post.reload.tag_string)
     end
 
-    should "move saved searches" do
-      ss = create(:saved_search, user: @user, query: "123 ... 456")
-      TagBatchChangeJob.perform_now("...", "bbb", @user, "127.0.0.1")
-      assert_equal("123 456 bbb", ss.reload.normalized_query)
-    end
-
-    should "move blacklists" do
-      @user.update(blacklisted_tags: "123 456\n789\n")
-      TagBatchChangeJob.perform_now("456", "xxx", @user, "127.0.0.1")
-
-      assert_equal("123 xxx\n789", @user.reload.blacklisted_tags)
-    end
-
-    should "move only saved searches that match the mass update exactly" do
-      ss = create(:saved_search, user: @user, query: "123 ... 456")
-
-      TagBatchChangeJob.perform_now("1", "bbb", @user, "127.0.0.1")
-      assert_equal("... 123 456", ss.reload.normalized_query, "expected '123' to remain unchanged")
-
-      TagBatchChangeJob.perform_now("123 456", "789", @user, "127.0.0.1")
-      assert_equal("... 789", ss.reload.normalized_query, "expected '123 456' to be changed to '789'")
-    end
-
     should "log a modaction" do
-      TagBatchChangeJob.perform_now("1", "2", @user, "127.0.0.1")
+      TagBatchChangeJob.perform_now("1", "2")
       assert_equal("mass_update", ModAction.last.category)
     end
-
-    should "raise an error if there is no predicate" do
-      assert_raises(TagBatchChangeJob::Error) do
-        TagBatchChangeJob.perform_now("", "bbb", @user, "127.0.0.1")
-      end
-    end
   end
 end

test/unit/bulk_update_request_test.rb

@@ -182,6 +182,35 @@ class BulkUpdateRequestTest < ActiveSupport::TestCase
           assert_equal("Imageboard", @post.reload.source)
         end
       end
+
+      context "the rename command" do
+        setup do
+          @artist = create(:artist, name: "foo")
+          @wiki = create(:wiki_page, title: "foo", body: "[[foo]]")
+          @post = create(:post, tag_string: "foo blah")
+          @bur = create(:bulk_update_request, script: "rename foo -> bar")
+          @bur.approve!(@admin)
+          perform_enqueued_jobs
+        end
+
+        should "rename the tags" do
+          assert_equal("approved", @bur.status)
+          assert_equal("bar blah", @post.reload.tag_string)
+        end
+
+        should "move the tag's artist entry and wiki page" do
+          assert_equal("bar", @artist.reload.name)
+          assert_equal("bar", @wiki.reload.title)
+          assert_equal("[[bar]]", @wiki.body)
+        end
+
+        should "fail if the old tag doesn't exist" do
+          @bur = build(:bulk_update_request, script: "rename aaa -> bbb")
+
+          assert_equal(false, @bur.valid?)
+          assert_equal(["Can't rename aaa -> bbb (the 'aaa' tag doesn't exist)"], @bur.errors.full_messages)
+        end
+      end
     end
 
     context "when validating a script" do