FEATURE: show existing tag name on rename modal

FIX: tags_filter_regexp was not being applied on tag rename

app/assets/javascripts/discourse/app/controllers/rename-tag.js

@@ -3,9 +3,12 @@ import Controller from "@ember/controller";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import BufferedContent from "discourse/mixins/buffered-content";
 import { extractError } from "discourse/lib/ajax-error";
+import { oneWay } from "@ember/object/computed";
 
 export default Controller.extend(ModalFunctionality, BufferedContent, {
-  @discourseComputed("buffered.id", "id")
+  tagId: oneWay("model.id"),
+
+  @discourseComputed("tagId", "model.id")
   renameDisabled(inputTagName, currentTagName) {
     const filterRegexp = new RegExp(this.site.tags_filter_regexp, "g");
     const newTagName = inputTagName
@@ -18,7 +21,7 @@ export default Controller.extend(ModalFunctionality, BufferedContent, {
   actions: {
     performRename() {
       this.model
-        .update({ id: this.get("buffered.id") })
+        .update({ id: this.get("tagId") })
         .then((result) => {
           this.send("closeModal");
 

app/assets/javascripts/discourse/app/templates/modal/rename-tag.hbs

@@ -3,7 +3,7 @@
     {{i18n "tagging.rename_instructions"}}
   </label>
   <div class="controls">
-    {{input value=buffered.id maxlength=siteSettings.max_tag_length}}
+    {{input value=tagId maxlength=siteSettings.max_tag_length}}
   </div>
 {{/d-modal-body}}