From 09223e5ae72ff1ced8f08143b7578122b462c6d6 Mon Sep 17 00:00:00 2001
From: Martin Brennan <martin@discourse.org>
Date: Tue, 8 Aug 2023 11:18:55 +1000
Subject: [PATCH] DEV: Remove enable_experimental_hashtag_autocomplete logic
 (#22820)

This commit removes any logic in the app and in specs around
enable_experimental_hashtag_autocomplete and deletes some
old category hashtag code that is no longer necessary.

It also adds a `slug_ref` category instance method, which
will generate a reference like `parent:child` for a category,
with an optional depth, which hashtags use. Also refactors
PostRevisor which was using CategoryHashtagDataSource directly
which is a no-no.

Deletes the old hashtag markdown rule as well.
---
 .../app/components/composer-editor.js         |  32 +-
 .../discourse/app/components/d-editor.js      |  12 +-
 .../hashtag-post-decorations.js               |  11 +-
 .../discourse/app/lib/hashtag-autocomplete.js |  39 +-
 .../discourse/app/lib/link-hashtags.js        |   3 +
 .../acceptance/hashtag-autocomplete-test.js   |   1 -
 .../tests/acceptance/hashtags-test.js         |  51 --
 .../tests/unit/lib/pretty-text-test.js        |  67 ---
 .../addon/engines/discourse-markdown-it.js    |   2 -
 .../pretty-text/addon/pretty-text.js          |   2 -
 .../discourse-markdown/category-hashtag.js    |  65 ---
 .../hashtag-autocomplete.js                   |  15 +-
 app/controllers/hashtags_controller.rb        |   6 +-
 app/models/category.rb                        |  16 +
 app/models/concerns/category_hashtag.rb       |  21 +-
 app/services/category_hashtag_data_source.rb  |   9 +-
 app/services/hashtag_autocomplete_service.rb  |  45 --
 app/services/tag_hashtag_data_source.rb       |   2 +-
 lib/post_revisor.rb                           |   8 +-
 lib/pretty_text.rb                            |   6 +-
 lib/pretty_text/helpers.rb                    |  15 -
 lib/pretty_text/shims.js                      |   6 -
 .../chat/lib/chat/channel_archive_service.rb  |   4 +-
 .../lib/chat/channel_hashtag_data_source.rb   |   2 +-
 .../lib/chat/channel_archive_service_spec.rb  |  40 +-
 .../chat/channel_hashtag_data_source_spec.rb  |   1 -
 plugins/chat/spec/models/chat/message_spec.rb |  15 -
 .../spec/system/hashtag_autocomplete_spec.rb  |   2 -
 .../config/locales/server.en.yml              |  10 -
 .../advanced_user_narrative.rb                |  39 +-
 .../advanced_user_narrative_spec.rb           |  39 +-
 spec/integrity/common_mark_spec.rb            |   5 +-
 spec/lib/concern/category_hashtag_spec.rb     |  51 --
 spec/lib/email/sender_spec.rb                 |   1 -
 spec/lib/oneboxer_spec.rb                     |   1 -
 spec/lib/pretty_text/helpers_spec.rb          |  31 --
 spec/lib/pretty_text_spec.rb                  |  88 +---
 spec/models/category_spec.rb                  |  33 ++
 spec/requests/hashtags_controller_spec.rb     | 447 +++++++-----------
 .../hashtag_autocomplete_service_spec.rb      |  47 --
 spec/services/post_alerter_spec.rb            |   3 +-
 spec/system/hashtag_autocomplete_spec.rb      |   7 +-
 spec/tasks/hashtags_spec.rb                   |  11 +-
 43 files changed, 310 insertions(+), 1001 deletions(-)
 delete mode 100644 app/assets/javascripts/discourse/tests/acceptance/hashtags-test.js
 delete mode 100644 app/assets/javascripts/pretty-text/engines/discourse-markdown/category-hashtag.js
 delete mode 100644 spec/lib/concern/category_hashtag_spec.rb

diff --git a/app/assets/javascripts/discourse/app/components/composer-editor.js b/app/assets/javascripts/discourse/app/components/composer-editor.js
index 6673c23f375..b74a0c5ec0d 100644
--- a/app/assets/javascripts/discourse/app/components/composer-editor.js
+++ b/app/assets/javascripts/discourse/app/components/composer-editor.js
@@ -14,10 +14,6 @@ import discourseComputed, {
   observes,
   on,
 } from "discourse-common/utils/decorators";
-import {
-  fetchUnseenHashtags,
-  linkSeenHashtags,
-} from "discourse/lib/link-hashtags";
 import {
   fetchUnseenHashtagsInContext,
   linkSeenHashtagsInContext,
@@ -500,24 +496,12 @@ export default Component.extend(
     },
 
     _renderUnseenHashtags(preview) {
-      let unseen;
       const hashtagContext = this.site.hashtag_configurations["topic-composer"];
-      if (this.siteSettings.enable_experimental_hashtag_autocomplete) {
-        unseen = linkSeenHashtagsInContext(hashtagContext, preview);
-      } else {
-        unseen = linkSeenHashtags(preview);
-      }
-
+      const unseen = linkSeenHashtagsInContext(hashtagContext, preview);
       if (unseen.length > 0) {
-        if (this.siteSettings.enable_experimental_hashtag_autocomplete) {
-          fetchUnseenHashtagsInContext(hashtagContext, unseen).then(() => {
-            linkSeenHashtagsInContext(hashtagContext, preview);
-          });
-        } else {
-          fetchUnseenHashtags(unseen).then(() => {
-            linkSeenHashtags(preview);
-          });
-        }
+        fetchUnseenHashtagsInContext(hashtagContext, unseen).then(() => {
+          linkSeenHashtagsInContext(hashtagContext, preview);
+        });
       }
     },
 
@@ -946,15 +930,9 @@ export default Component.extend(
         this._warnCannotSeeMention(preview);
 
         // Paint category, tag, and other data source hashtags
-        let unseenHashtags;
         const hashtagContext =
           this.site.hashtag_configurations["topic-composer"];
-        if (this.siteSettings.enable_experimental_hashtag_autocomplete) {
-          unseenHashtags = linkSeenHashtagsInContext(hashtagContext, preview);
-        } else {
-          unseenHashtags = linkSeenHashtags(preview);
-        }
-        if (unseenHashtags.length > 0) {
+        if (linkSeenHashtagsInContext(hashtagContext, preview).length > 0) {
           discourseDebounce(this, this._renderUnseenHashtags, preview, 450);
         }
 
diff --git a/app/assets/javascripts/discourse/app/components/d-editor.js b/app/assets/javascripts/discourse/app/components/d-editor.js
index 019a6780964..22a685cd204 100644
--- a/app/assets/javascripts/discourse/app/components/d-editor.js
+++ b/app/assets/javascripts/discourse/app/components/d-editor.js
@@ -18,13 +18,15 @@ import I18n from "I18n";
 import ItsATrap from "@discourse/itsatrap";
 import { Promise } from "rsvp";
 import { SKIP } from "discourse/lib/autocomplete";
-import { setupHashtagAutocomplete } from "discourse/lib/hashtag-autocomplete";
+import {
+  linkSeenHashtagsInContext,
+  setupHashtagAutocomplete,
+} from "discourse/lib/hashtag-autocomplete";
 import deprecated from "discourse-common/lib/deprecated";
 import discourseDebounce from "discourse-common/lib/debounce";
 import { findRawTemplate } from "discourse-common/lib/raw-templates";
 import { getRegister } from "discourse-common/lib/get-owner";
 import { isTesting } from "discourse-common/config/environment";
-import { linkSeenHashtags } from "discourse/lib/link-hashtags";
 import { linkSeenMentions } from "discourse/lib/link-mentions";
 import { loadOneboxes } from "discourse/lib/load-oneboxes";
 import loadScript from "discourse/lib/load-script";
@@ -438,8 +440,10 @@ export default Component.extend(TextareaTextManipulation, {
       if (this.siteSettings.enable_diffhtml_preview) {
         const cookedElement = document.createElement("div");
         cookedElement.innerHTML = cooked;
-
-        linkSeenHashtags(cookedElement);
+        linkSeenHashtagsInContext(
+          this.site.hashtag_configurations["topic-composer"],
+          cookedElement
+        );
         linkSeenMentions(cookedElement, this.siteSettings);
         resolveCachedShortUrls(this.siteSettings, cookedElement);
         loadOneboxes(
diff --git a/app/assets/javascripts/discourse/app/instance-initializers/hashtag-post-decorations.js b/app/assets/javascripts/discourse/app/instance-initializers/hashtag-post-decorations.js
index 75b462d0ddc..f3221dc88ba 100644
--- a/app/assets/javascripts/discourse/app/instance-initializers/hashtag-post-decorations.js
+++ b/app/assets/javascripts/discourse/app/instance-initializers/hashtag-post-decorations.js
@@ -5,16 +5,13 @@ export default {
   after: "hashtag-css-generator",
 
   initialize(owner) {
-    const siteSettings = owner.lookup("service:site-settings");
     const site = owner.lookup("service:site");
 
     withPluginApi("0.8.7", (api) => {
-      if (siteSettings.enable_experimental_hashtag_autocomplete) {
-        api.decorateCookedElement((post) => decorateHashtags(post, site), {
-          onlyStream: true,
-          id: "hashtag-icons",
-        });
-      }
+      api.decorateCookedElement((post) => decorateHashtags(post, site), {
+        onlyStream: true,
+        id: "hashtag-icons",
+      });
     });
   },
 };
diff --git a/app/assets/javascripts/discourse/app/lib/hashtag-autocomplete.js b/app/assets/javascripts/discourse/app/lib/hashtag-autocomplete.js
index defdb468bf5..d23af5d5b32 100644
--- a/app/assets/javascripts/discourse/app/lib/hashtag-autocomplete.js
+++ b/app/assets/javascripts/discourse/app/lib/hashtag-autocomplete.js
@@ -11,7 +11,6 @@ import {
   escapeExpression,
   inCodeBlock,
 } from "discourse/lib/utilities";
-import { search as searchCategoryTag } from "discourse/lib/category-tag-search";
 import { emojiUnescape } from "discourse/lib/text";
 import { htmlSafe } from "@ember/template";
 
@@ -76,16 +75,12 @@ export function setupHashtagAutocomplete(
   siteSettings,
   autocompleteOptions = {}
 ) {
-  if (siteSettings.enable_experimental_hashtag_autocomplete) {
-    _setupExperimental(
-      contextualHashtagConfiguration,
-      $textArea,
-      siteSettings,
-      autocompleteOptions
-    );
-  } else {
-    _setup($textArea, siteSettings, autocompleteOptions.afterComplete);
-  }
+  _setup(
+    contextualHashtagConfiguration,
+    $textArea,
+    siteSettings,
+    autocompleteOptions
+  );
 }
 
 export function hashtagTriggerRule(textarea) {
@@ -147,7 +142,7 @@ export function linkSeenHashtagsInContext(
     .filter((slug) => !checkedHashtags.has(slug));
 }
 
-function _setupExperimental(
+function _setup(
   contextualHashtagConfiguration,
   $textArea,
   siteSettings,
@@ -171,22 +166,6 @@ function _setupExperimental(
   });
 }
 
-function _setup($textArea, siteSettings, afterComplete) {
-  $textArea.autocomplete({
-    template: findRawTemplate("category-tag-autocomplete"),
-    key: "#",
-    afterComplete,
-    transformComplete: (obj) => obj.text,
-    dataSource: (term) => {
-      if (term.match(/\s/)) {
-        return null;
-      }
-      return searchCategoryTag(term, siteSettings);
-    },
-    triggerRule: (textarea, opts) => hashtagTriggerRule(textarea, opts),
-  });
-}
-
 let searchCache = {};
 let searchCacheTime;
 let currentSearch;
@@ -220,10 +199,6 @@ function _searchGeneric(term, siteSettings, contextualHashtagConfiguration) {
           resolve(CANCELLED_STATUS);
         }, 5000);
 
-    if (!siteSettings.enable_experimental_hashtag_autocomplete && term === "") {
-      return resolve(CANCELLED_STATUS);
-    }
-
     const debouncedSearch = (q, ctx, resultFunc) => {
       discourseDebounce(this, _searchRequest, q, ctx, resultFunc, INPUT_DELAY);
     };
diff --git a/app/assets/javascripts/discourse/app/lib/link-hashtags.js b/app/assets/javascripts/discourse/app/lib/link-hashtags.js
index 0138379fec5..42788dc269c 100644
--- a/app/assets/javascripts/discourse/app/lib/link-hashtags.js
+++ b/app/assets/javascripts/discourse/app/lib/link-hashtags.js
@@ -1,3 +1,6 @@
+// TODO (martin) Delete this after core PR and any other PRs that depend
+// on this file (e.g. discourse-encrypt) are merged.
+
 import deprecated from "discourse-common/lib/deprecated";
 import { TAG_HASHTAG_POSTFIX } from "discourse/lib/tag-hashtags";
 import { ajax } from "discourse/lib/ajax";
diff --git a/app/assets/javascripts/discourse/tests/acceptance/hashtag-autocomplete-test.js b/app/assets/javascripts/discourse/tests/acceptance/hashtag-autocomplete-test.js
index f6051259273..c6f0b6fcd6d 100644
--- a/app/assets/javascripts/discourse/tests/acceptance/hashtag-autocomplete-test.js
+++ b/app/assets/javascripts/discourse/tests/acceptance/hashtag-autocomplete-test.js
@@ -9,7 +9,6 @@ acceptance("#hashtag autocompletion in composer", function (needs) {
   needs.user();
   needs.settings({
     tagging_enabled: true,
-    enable_experimental_hashtag_autocomplete: true,
   });
   needs.pretender((server, helper) => {
     server.get("/hashtags", () => {
diff --git a/app/assets/javascripts/discourse/tests/acceptance/hashtags-test.js b/app/assets/javascripts/discourse/tests/acceptance/hashtags-test.js
deleted file mode 100644
index 17111f33952..00000000000
--- a/app/assets/javascripts/discourse/tests/acceptance/hashtags-test.js
+++ /dev/null
@@ -1,51 +0,0 @@
-import {
-  acceptance,
-  query,
-  visible,
-} from "discourse/tests/helpers/qunit-helpers";
-import { click, fillIn, visit } from "@ember/test-helpers";
-import { test } from "qunit";
-
-acceptance("Category and Tag Hashtags", function (needs) {
-  needs.user();
-  needs.settings({
-    tagging_enabled: true,
-    enable_experimental_hashtag_autocomplete: false,
-  });
-  needs.pretender((server, helper) => {
-    server.get("/hashtags", () => {
-      return helper.response({
-        categories: { bug: "/c/bugs" },
-        tags: {
-          monkey: "/tag/monkey",
-          bug: "/tag/bug",
-        },
-      });
-    });
-  });
-
-  test("hashtags are cooked properly", async function (assert) {
-    await visit("/t/internationalization-localization/280");
-    await click("#topic-footer-buttons .btn.create");
-
-    await fillIn(
-      ".d-editor-input",
-      `this is a category hashtag #bug
-
-this is a tag hashtag #monkey
-
-category vs tag: #bug vs #bug::tag
-
-uppercase hashtag works too #BUG, #BUG::tag`
-    );
-
-    assert.ok(visible(".d-editor-preview"));
-    assert.strictEqual(
-      query(".d-editor-preview").innerHTML.trim(),
-      `<p>this is a category hashtag <a href="/c/bugs" class="hashtag" tabindex=\"-1\">#<span>bug</span></a></p>
-<p>this is a tag hashtag <a href="/tag/monkey" class="hashtag" tabindex=\"-1\">#<span>monkey</span></a></p>
-<p>category vs tag: <a href="/c/bugs" class="hashtag" tabindex=\"-1\">#<span>bug</span></a> vs <a href="/tag/bug" class="hashtag" tabindex=\"-1\">#<span>bug</span></a></p>
-<p>uppercase hashtag works too <a href="/c/bugs" class="hashtag" tabindex=\"-1\">#<span>BUG</span></a>, <a href="/tag/bug" class="hashtag" tabindex=\"-1\">#<span>BUG</span></a></p>`
-    );
-  });
-});
diff --git a/app/assets/javascripts/discourse/tests/unit/lib/pretty-text-test.js b/app/assets/javascripts/discourse/tests/unit/lib/pretty-text-test.js
index c909f43b9ac..f018c85d3e6 100644
--- a/app/assets/javascripts/discourse/tests/unit/lib/pretty-text-test.js
+++ b/app/assets/javascripts/discourse/tests/unit/lib/pretty-text-test.js
@@ -643,73 +643,6 @@ eviltrout</p>
     );
   });
 
-  test("Category hashtags", function (assert) {
-    const alwaysTrue = {
-      categoryHashtagLookup: function () {
-        return [
-          "http://test.discourse.org/category-hashtag",
-          "category-hashtag",
-        ];
-      },
-    };
-
-    assert.cookedOptions(
-      "Check out #category-hashtag",
-      alwaysTrue,
-      '<p>Check out <a class="hashtag" href="http://test.discourse.org/category-hashtag">#<span>category-hashtag</span></a></p>',
-      "it translates category hashtag into links"
-    );
-
-    assert.cooked(
-      "Check out #category-hashtag",
-      '<p>Check out <span class="hashtag">#category-hashtag</span></p>',
-      "it does not translate category hashtag into links if it is not a valid category hashtag"
-    );
-
-    assert.cookedOptions(
-      "[#category-hashtag](http://www.test.com)",
-      alwaysTrue,
-      '<p><a href="http://www.test.com">#category-hashtag</a></p>',
-      "it does not translate category hashtag within links"
-    );
-
-    assert.cooked(
-      "```\n# #category-hashtag\n```",
-      '<pre><code class="lang-auto"># #category-hashtag\n</code></pre>',
-      "it does not translate category hashtags to links in code blocks"
-    );
-
-    assert.cooked(
-      "># #category-hashtag\n",
-      '<blockquote>\n<h1><span class="hashtag">#category-hashtag</span></h1>\n</blockquote>',
-      "it handles category hashtags in simple quotes"
-    );
-
-    assert.cooked(
-      "# #category-hashtag",
-      '<h1><a name="category-hashtag-1" class="anchor" href="#category-hashtag-1"></a><span class="hashtag">#category-hashtag</span></h1>',
-      "it works within ATX-style headers"
-    );
-
-    assert.cooked(
-      "don't `#category-hashtag`",
-      "<p>don't <code>#category-hashtag</code></p>",
-      "it does not mention in an inline code block"
-    );
-
-    assert.cooked(
-      "<small>#category-hashtag</small>",
-      '<p><small><span class="hashtag">#category-hashtag</span></small></p>',
-      "it works between HTML tags"
-    );
-
-    assert.cooked(
-      "Checkout #ụdị",
-      '<p>Checkout <span class="hashtag">#ụdị</span></p>',
-      "it works for non-english characters"
-    );
-  });
-
   test("Heading", function (assert) {
     assert.cooked(
       "**Bold**\n----------",
diff --git a/app/assets/javascripts/pretty-text/addon/engines/discourse-markdown-it.js b/app/assets/javascripts/pretty-text/addon/engines/discourse-markdown-it.js
index 84f8ce8c37a..e15ff31af27 100644
--- a/app/assets/javascripts/pretty-text/addon/engines/discourse-markdown-it.js
+++ b/app/assets/javascripts/pretty-text/addon/engines/discourse-markdown-it.js
@@ -547,8 +547,6 @@ export function setup(opts, siteSettings, state) {
     markdownTypographerQuotationMarks:
       siteSettings.markdown_typographer_quotation_marks,
     markdownLinkifyTlds: siteSettings.markdown_linkify_tlds,
-    enableExperimentalHashtagAutocomplete:
-      siteSettings.enable_experimental_hashtag_autocomplete,
   };
 
   const markdownitOpts = {
diff --git a/app/assets/javascripts/pretty-text/addon/pretty-text.js b/app/assets/javascripts/pretty-text/addon/pretty-text.js
index 7d572eb5be5..f0e93ae1282 100644
--- a/app/assets/javascripts/pretty-text/addon/pretty-text.js
+++ b/app/assets/javascripts/pretty-text/addon/pretty-text.js
@@ -28,7 +28,6 @@ export function buildOptions(state) {
     getTopicInfo,
     topicId,
     forceQuoteLink,
-    categoryHashtagLookup,
     userId,
     getCurrentUser,
     currentUser,
@@ -67,7 +66,6 @@ export function buildOptions(state) {
     getTopicInfo,
     topicId,
     forceQuoteLink,
-    categoryHashtagLookup,
     userId,
     getCurrentUser,
     currentUser,
diff --git a/app/assets/javascripts/pretty-text/engines/discourse-markdown/category-hashtag.js b/app/assets/javascripts/pretty-text/engines/discourse-markdown/category-hashtag.js
deleted file mode 100644
index 65595603b85..00000000000
--- a/app/assets/javascripts/pretty-text/engines/discourse-markdown/category-hashtag.js
+++ /dev/null
@@ -1,65 +0,0 @@
-// TODO (martin) Remove this once enable_experimental_hashtag_autocomplete
-// (and by extension enableExperimentalHashtagAutocomplete) is not required
-// anymore, the new hashtag-autocomplete rule replaces it.
-
-function addHashtag(buffer, matches, state) {
-  const options = state.md.options.discourse;
-  const slug = matches[1];
-  const categoryHashtagLookup = options.categoryHashtagLookup;
-  const result = categoryHashtagLookup && categoryHashtagLookup(slug);
-
-  let token;
-
-  if (result) {
-    token = new state.Token("link_open", "a", 1);
-    token.attrs = [
-      ["class", "hashtag"],
-      ["href", result[0]],
-    ];
-    token.block = false;
-    buffer.push(token);
-
-    token = new state.Token("text", "", 0);
-    token.content = "#";
-    buffer.push(token);
-
-    token = new state.Token("span_open", "span", 1);
-    token.block = false;
-    buffer.push(token);
-
-    token = new state.Token("text", "", 0);
-    token.content = result[1];
-    buffer.push(token);
-
-    buffer.push(new state.Token("span_close", "span", -1));
-
-    buffer.push(new state.Token("link_close", "a", -1));
-  } else {
-    token = new state.Token("span_open", "span", 1);
-    token.attrs = [["class", "hashtag"]];
-    buffer.push(token);
-
-    token = new state.Token("text", "", 0);
-    token.content = matches[0];
-    buffer.push(token);
-
-    token = new state.Token("span_close", "span", -1);
-    buffer.push(token);
-  }
-}
-
-export function setup(helper) {
-  helper.registerPlugin((md) => {
-    if (
-      !md.options.discourse.limitedSiteSettings
-        .enableExperimentalHashtagAutocomplete
-    ) {
-      const rule = {
-        matcher: /#([\u00C0-\u1FFF\u2C00-\uD7FF\w:-]{1,101})/,
-        onMatch: addHashtag,
-      };
-
-      md.core.textPostProcess.ruler.push("category-hashtag", rule);
-    }
-  });
-}
diff --git a/app/assets/javascripts/pretty-text/engines/discourse-markdown/hashtag-autocomplete.js b/app/assets/javascripts/pretty-text/engines/discourse-markdown/hashtag-autocomplete.js
index 42a14b3d2d2..cc808d7afe3 100644
--- a/app/assets/javascripts/pretty-text/engines/discourse-markdown/hashtag-autocomplete.js
+++ b/app/assets/javascripts/pretty-text/engines/discourse-markdown/hashtag-autocomplete.js
@@ -87,17 +87,12 @@ function addIconPlaceholder(buffer, state) {
 
 export function setup(helper) {
   helper.registerPlugin((md) => {
-    if (
-      md.options.discourse.limitedSiteSettings
-        .enableExperimentalHashtagAutocomplete
-    ) {
-      const rule = {
-        matcher: /#([\u00C0-\u1FFF\u2C00-\uD7FF\w:-]{1,101})/,
-        onMatch: addHashtag,
-      };
+    const rule = {
+      matcher: /#([\u00C0-\u1FFF\u2C00-\uD7FF\w:-]{1,101})/,
+      onMatch: addHashtag,
+    };
 
-      md.core.textPostProcess.ruler.push("hashtag-autocomplete", rule);
-    }
+    md.core.textPostProcess.ruler.push("hashtag-autocomplete", rule);
   });
 
   helper.allowList([
diff --git a/app/controllers/hashtags_controller.rb b/app/controllers/hashtags_controller.rb
index e55b6840227..e650bf16943 100644
--- a/app/controllers/hashtags_controller.rb
+++ b/app/controllers/hashtags_controller.rb
@@ -4,11 +4,7 @@ class HashtagsController < ApplicationController
   requires_login
 
   def lookup
-    if SiteSetting.enable_experimental_hashtag_autocomplete
-      render json: HashtagAutocompleteService.new(guardian).lookup(params[:slugs], params[:order])
-    else
-      render json: HashtagAutocompleteService.new(guardian).lookup_old(params[:slugs])
-    end
+    render json: HashtagAutocompleteService.new(guardian).lookup(params[:slugs], params[:order])
   end
 
   def search
diff --git a/app/models/category.rb b/app/models/category.rb
index b0cadea1853..c244b7bf3a8 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -18,6 +18,8 @@ class Category < ActiveRecord::Base
 
   REQUIRE_TOPIC_APPROVAL = "require_topic_approval"
   REQUIRE_REPLY_APPROVAL = "require_reply_approval"
+  NUM_AUTO_BUMP_DAILY = "num_auto_bump_daily"
+  SLUG_REF_SEPARATOR = ":"
 
   register_custom_field_type(REQUIRE_TOPIC_APPROVAL, :boolean)
   register_custom_field_type(REQUIRE_REPLY_APPROVAL, :boolean)
@@ -1037,6 +1039,20 @@ class Category < ActiveRecord::Base
     end
   end
 
+  def slug_ref(depth: 1)
+    if self.parent_category_id.present?
+      built_ref = [self.slug]
+      parent = self.parent_category
+      while parent.present? && (built_ref.length < depth + 1)
+        built_ref << parent.slug
+        parent = parent.parent_category
+      end
+      built_ref.reverse.join(Category::SLUG_REF_SEPARATOR)
+    else
+      self.slug
+    end
+  end
+
   def cannot_delete_reason
     return I18n.t("category.cannot_delete.uncategorized") if self.uncategorized?
     return I18n.t("category.cannot_delete.has_subcategories") if self.has_children?
diff --git a/app/models/concerns/category_hashtag.rb b/app/models/concerns/category_hashtag.rb
index 00f4e3e74f3..d8044399a8e 100644
--- a/app/models/concerns/category_hashtag.rb
+++ b/app/models/concerns/category_hashtag.rb
@@ -3,26 +3,7 @@
 module CategoryHashtag
   extend ActiveSupport::Concern
 
-  SEPARATOR = ":"
-
   class_methods do
-    # TODO (martin) Remove this when enable_experimental_hashtag_autocomplete
-    # becomes the norm, it is reimplemented below for CategoryHashtagDataSourcee
-    def query_from_hashtag_slug(category_slug)
-      slug_path = split_slug_path(category_slug)
-      return if slug_path.blank?
-
-      slug_path.map! { |slug| CGI.escape(slug) } if SiteSetting.slug_generation_method == "encoded"
-
-      parent_slug, child_slug = slug_path.last(2)
-      categories = Category.where(slug: parent_slug)
-      if child_slug
-        Category.where(slug: child_slug, parent_category_id: categories.select(:id)).first
-      else
-        categories.where(parent_category_id: nil).first
-      end
-    end
-
     ##
     # Finds any categories that match the provided slugs, supporting
     # the parent:child format for category slugs (only one level of
@@ -66,7 +47,7 @@ module CategoryHashtag
     end
 
     def split_slug_path(slug)
-      slug_path = slug.split(SEPARATOR)
+      slug_path = slug.split(Category::SLUG_REF_SEPARATOR)
       return if slug_path.empty? || slug_path.size > 2
       slug_path
     end
diff --git a/app/services/category_hashtag_data_source.rb b/app/services/category_hashtag_data_source.rb
index 960c383ad89..e75d3e74c77 100644
--- a/app/services/category_hashtag_data_source.rb
+++ b/app/services/category_hashtag_data_source.rb
@@ -5,7 +5,7 @@
 # categories via the # autocomplete character.
 class CategoryHashtagDataSource
   def self.enabled?
-    SiteSetting.enable_experimental_hashtag_autocomplete
+    true
   end
 
   def self.icon
@@ -27,12 +27,7 @@ class CategoryHashtagDataSource
 
       # Single-level category heirarchy should be enough to distinguish between
       # categories here.
-      item.ref =
-        if category.parent_category_id
-          "#{category.parent_category.slug}:#{category.slug}"
-        else
-          category.slug
-        end
+      item.ref = category.slug_ref
     end
   end
 
diff --git a/app/services/hashtag_autocomplete_service.rb b/app/services/hashtag_autocomplete_service.rb
index 65ee0a2e061..4ed2bea573e 100644
--- a/app/services/hashtag_autocomplete_service.rb
+++ b/app/services/hashtag_autocomplete_service.rb
@@ -299,51 +299,6 @@ class HashtagAutocompleteService
     append_types_to_conflicts(limited_results, top_ranked_type, types_in_priority_order, limit)
   end
 
-  # TODO (martin) Remove this once plugins are not relying on the old lookup
-  # behavior via HashtagsController when enable_experimental_hashtag_autocomplete is removed
-  def lookup_old(slugs)
-    raise Discourse::InvalidParameters.new(:slugs) if !slugs.is_a?(Array)
-
-    all_slugs = []
-    tag_slugs = []
-
-    slugs[0..HashtagAutocompleteService::HASHTAGS_PER_REQUEST].each do |slug|
-      if slug.end_with?(PrettyText::Helpers::TAG_HASHTAG_POSTFIX)
-        tag_slugs << slug.chomp(PrettyText::Helpers::TAG_HASHTAG_POSTFIX)
-      else
-        all_slugs << slug
-      end
-    end
-
-    # Try to resolve hashtags as categories first
-    category_slugs_and_ids =
-      all_slugs.map { |slug| [slug, Category.query_from_hashtag_slug(slug)&.id] }.to_h
-    category_ids_and_urls =
-      Category
-        .secured(guardian)
-        .select(:id, :slug, :parent_category_id) # fields required for generating category URL
-        .where(id: category_slugs_and_ids.values)
-        .map { |c| [c.id, c.url] }
-        .to_h
-    categories_hashtags = {}
-    category_slugs_and_ids.each do |slug, id|
-      if category_url = category_ids_and_urls[id]
-        categories_hashtags[slug] = category_url
-      end
-    end
-
-    # Resolve remaining hashtags as tags
-    tag_hashtags = {}
-    if SiteSetting.tagging_enabled
-      tag_slugs += (all_slugs - categories_hashtags.keys)
-      DiscourseTagging
-        .filter_visible(Tag.where_name(tag_slugs), guardian)
-        .each { |tag| tag_hashtags[tag.name] = tag.full_url }
-    end
-
-    { categories: categories_hashtags, tags: tag_hashtags }
-  end
-
   private
 
   def search_using_condition(limited_results, term, type, limit, condition)
diff --git a/app/services/tag_hashtag_data_source.rb b/app/services/tag_hashtag_data_source.rb
index caaf8d3c4b4..531a3b16add 100644
--- a/app/services/tag_hashtag_data_source.rb
+++ b/app/services/tag_hashtag_data_source.rb
@@ -5,7 +5,7 @@
 # tags via the # autocomplete character.
 class TagHashtagDataSource
   def self.enabled?
-    SiteSetting.enable_experimental_hashtag_autocomplete && SiteSetting.tagging_enabled
+    SiteSetting.tagging_enabled
   end
 
   def self.icon
diff --git a/lib/post_revisor.rb b/lib/post_revisor.rb
index 6ab8c9afaec..498ff537ab2 100644
--- a/lib/post_revisor.rb
+++ b/lib/post_revisor.rb
@@ -160,18 +160,14 @@ class PostRevisor
       user,
       I18n.t(
         "topic_category_changed",
-        from: category_name_raw(old_category),
-        to: category_name_raw(new_category),
+        from: "##{old_category.slug_ref}",
+        to: "##{new_category.slug_ref}",
       ),
       post_type: Post.types[:small_action],
       action_code: "category_changed",
     )
   end
 
-  def self.category_name_raw(category)
-    "##{CategoryHashtagDataSource.category_to_hashtag_item(category).ref}"
-  end
-
   def self.create_small_action_for_tag_changes(topic:, user:, added_tags:, removed_tags:)
     return if !SiteSetting.create_post_for_category_and_tag_changes
 
diff --git a/lib/pretty_text.rb b/lib/pretty_text.rb
index f33268f2127..12289d2a1b6 100644
--- a/lib/pretty_text.rb
+++ b/lib/pretty_text.rb
@@ -197,7 +197,6 @@ module PrettyText
         __optInput.lookupPrimaryUserGroup = __lookupPrimaryUserGroup;
         __optInput.formatUsername = __formatUsername;
         __optInput.getTopicInfo = __getTopicInfo;
-        __optInput.categoryHashtagLookup = __categoryLookup;
         __optInput.hashtagLookup = __hashtagLookup;
         __optInput.customEmoji = #{custom_emoji.to_json};
         __optInput.customEmojiTranslation = #{Plugin::CustomEmoji.translations.to_json};
@@ -471,10 +470,7 @@ module PrettyText
     DiscourseEvent.trigger(:reduce_excerpt, doc, options)
     strip_image_wrapping(doc)
     strip_oneboxed_media(doc)
-
-    if SiteSetting.enable_experimental_hashtag_autocomplete && options[:plain_hashtags]
-      convert_hashtag_links_to_plaintext(doc)
-    end
+    convert_hashtag_links_to_plaintext(doc) if options[:plain_hashtags]
 
     html = doc.to_html
     ExcerptParser.get_excerpt(html, max_length, options)
diff --git a/lib/pretty_text/helpers.rb b/lib/pretty_text/helpers.rb
index 5f48b28bbdc..b07951ed79a 100644
--- a/lib/pretty_text/helpers.rb
+++ b/lib/pretty_text/helpers.rb
@@ -96,21 +96,6 @@ module PrettyText
       end
     end
 
-    # TODO (martin) Remove this when everything is using hashtag_lookup
-    # after enable_experimental_hashtag_autocomplete is default.
-    def category_tag_hashtag_lookup(text)
-      is_tag = text =~ /#{TAG_HASHTAG_POSTFIX}\z/
-
-      if !is_tag && category = Category.query_from_hashtag_slug(text)
-        [category.url, text]
-      elsif (!is_tag && tag = Tag.find_by(name: text)) ||
-            (is_tag && tag = Tag.find_by(name: text.gsub!(TAG_HASHTAG_POSTFIX, "")))
-        [tag.url, text]
-      else
-        nil
-      end
-    end
-
     def hashtag_lookup(slug, cooking_user_id, types_in_priority_order)
       # NOTE: This is _somewhat_ expected since we need to be able to cook posts
       # etc. without a user sometimes, but it is still an edge case.
diff --git a/lib/pretty_text/shims.js b/lib/pretty_text/shims.js
index f0d7b0849f1..ab8ded97ea1 100644
--- a/lib/pretty_text/shims.js
+++ b/lib/pretty_text/shims.js
@@ -106,12 +106,6 @@ function __getTopicInfo(i) {
   return __helpers.get_topic_info(i);
 }
 
-// TODO (martin) Remove this when everything is using hashtag_lookup
-// after enable_experimental_hashtag_autocomplete is default.
-function __categoryLookup(c) {
-  return __helpers.category_tag_hashtag_lookup(c);
-}
-
 function __hashtagLookup(slug, cookingUserId, typesInPriorityOrder) {
   return __helpers.hashtag_lookup(slug, cookingUserId, typesInPriorityOrder);
 }
diff --git a/plugins/chat/lib/chat/channel_archive_service.rb b/plugins/chat/lib/chat/channel_archive_service.rb
index d3d7a349588..3dffdb76923 100644
--- a/plugins/chat/lib/chat/channel_archive_service.rb
+++ b/plugins/chat/lib/chat/channel_archive_service.rb
@@ -301,9 +301,7 @@ module Chat
     end
 
     def channel_hashtag_or_name
-      if chat_channel.slug.present? && SiteSetting.enable_experimental_hashtag_autocomplete
-        return "##{chat_channel.slug}::channel"
-      end
+      return "##{chat_channel.slug}::channel" if chat_channel.slug.present?
       chat_channel_title
     end
   end
diff --git a/plugins/chat/lib/chat/channel_hashtag_data_source.rb b/plugins/chat/lib/chat/channel_hashtag_data_source.rb
index c5ccf8eff49..38276982bd2 100644
--- a/plugins/chat/lib/chat/channel_hashtag_data_source.rb
+++ b/plugins/chat/lib/chat/channel_hashtag_data_source.rb
@@ -3,7 +3,7 @@
 module Chat
   class ChannelHashtagDataSource
     def self.enabled?
-      SiteSetting.enable_experimental_hashtag_autocomplete && SiteSetting.enable_public_channels
+      SiteSetting.enable_public_channels
     end
 
     def self.icon
diff --git a/plugins/chat/spec/lib/chat/channel_archive_service_spec.rb b/plugins/chat/spec/lib/chat/channel_archive_service_spec.rb
index 1911e2fa3c6..2644914f2e7 100644
--- a/plugins/chat/spec/lib/chat/channel_archive_service_spec.rb
+++ b/plugins/chat/spec/lib/chat/channel_archive_service_spec.rb
@@ -186,28 +186,24 @@ describe Chat::ChannelArchiveService do
         expect(pm_topic.first_post.raw).to include("Title can't have more than 1 emoji")
       end
 
-      context "when enable_experimental_hashtag_autocomplete" do
-        before { SiteSetting.enable_experimental_hashtag_autocomplete = true }
-
-        it "uses the channel slug to autolink a hashtag for the channel in the PM" do
-          create_messages(3) && start_archive
-          described_class.new(@channel_archive).execute
-          expect(@channel_archive.reload.complete?).to eq(true)
-          pm_topic = Topic.private_messages.last
-          expect(pm_topic.first_post.cooked).to have_tag(
-            "a",
-            with: {
-              class: "hashtag-cooked",
-              href: channel.relative_url,
-              "data-type": "channel",
-              "data-slug": channel.slug,
-              "data-id": channel.id,
-              "data-ref": "#{channel.slug}::channel",
-            },
-          ) do
-            with_tag("span", with: { class: "hashtag-icon-placeholder" })
-            with_tag("span", text: channel.title(user))
-          end
+      it "uses the channel slug to autolink a hashtag for the channel in the PM" do
+        create_messages(3) && start_archive
+        described_class.new(@channel_archive).execute
+        expect(@channel_archive.reload.complete?).to eq(true)
+        pm_topic = Topic.private_messages.last
+        expect(pm_topic.first_post.cooked).to have_tag(
+          "a",
+          with: {
+            class: "hashtag-cooked",
+            href: channel.relative_url,
+            "data-type": "channel",
+            "data-slug": channel.slug,
+            "data-id": channel.id,
+            "data-ref": "#{channel.slug}::channel",
+          },
+        ) do
+          with_tag("span", with: { class: "hashtag-icon-placeholder" })
+          with_tag("span", text: channel.title(user))
         end
       end
 
diff --git a/plugins/chat/spec/lib/chat/channel_hashtag_data_source_spec.rb b/plugins/chat/spec/lib/chat/channel_hashtag_data_source_spec.rb
index 87c44e90e1c..fc4ff6955fa 100644
--- a/plugins/chat/spec/lib/chat/channel_hashtag_data_source_spec.rb
+++ b/plugins/chat/spec/lib/chat/channel_hashtag_data_source_spec.rb
@@ -27,7 +27,6 @@ RSpec.describe Chat::ChannelHashtagDataSource do
   let!(:guardian) { Guardian.new(user) }
 
   before do
-    SiteSetting.enable_experimental_hashtag_autocomplete = true
     SiteSetting.chat_allowed_groups = Group::AUTO_GROUPS[:trust_level_1]
     Group.refresh_automatic_groups!
   end
diff --git a/plugins/chat/spec/models/chat/message_spec.rb b/plugins/chat/spec/models/chat/message_spec.rb
index e0a5c232078..7b44fa94271 100644
--- a/plugins/chat/spec/models/chat/message_spec.rb
+++ b/plugins/chat/spec/models/chat/message_spec.rb
@@ -228,22 +228,8 @@ describe Chat::Message do
       expect(cooked).to eq("<p><span class=\"mention\">@mention</span></p>")
     end
 
-    it "supports category-hashtag plugin" do
-      # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-      SiteSetting.enable_experimental_hashtag_autocomplete = false
-
-      category = Fabricate(:category)
-
-      cooked = described_class.cook("##{category.slug}")
-
-      expect(cooked).to eq(
-        "<p><a class=\"hashtag\" href=\"#{category.url}\">#<span>#{category.slug}</span></a></p>",
-      )
-    end
-
     it "supports hashtag autocomplete" do
       SiteSetting.chat_enabled = true
-      SiteSetting.enable_experimental_hashtag_autocomplete = true
 
       category = Fabricate(:category)
       user = Fabricate(:user)
@@ -504,7 +490,6 @@ describe Chat::Message do
 
       before do
         SiteSetting.chat_enabled = true
-        SiteSetting.enable_experimental_hashtag_autocomplete = true
         SiteSetting.suppress_secured_categories_from_admin = true
       end
 
diff --git a/plugins/chat/spec/system/hashtag_autocomplete_spec.rb b/plugins/chat/spec/system/hashtag_autocomplete_spec.rb
index fa4b31e5648..898375f9ad4 100644
--- a/plugins/chat/spec/system/hashtag_autocomplete_spec.rb
+++ b/plugins/chat/spec/system/hashtag_autocomplete_spec.rb
@@ -15,8 +15,6 @@ describe "Using #hashtag autocompletion to search for and lookup channels", type
   let(:topic_page) { PageObjects::Pages::Topic.new }
 
   before do
-    SiteSetting.enable_experimental_hashtag_autocomplete = true
-
     chat_system_bootstrap(user, [channel1, channel2])
     sign_in(user)
   end
diff --git a/plugins/discourse-narrative-bot/config/locales/server.en.yml b/plugins/discourse-narrative-bot/config/locales/server.en.yml
index 97ce26d80f3..2bab753ac5a 100644
--- a/plugins/discourse-narrative-bot/config/locales/server.en.yml
+++ b/plugins/discourse-narrative-bot/config/locales/server.en.yml
@@ -400,18 +400,8 @@ en:
         instructions: |-
           Did you know that you can refer to categories and tags in your post? For example, have you seen the %{category} category?
 
-          Type `#` in the middle of a sentence and select any category or tag.
-        instructions_experimental: |-
-          Did you know that you can refer to categories and tags in your post? For example, have you seen the %{category} category?
-
           Type `#` anywhere in a sentence and select any category or tag.
         not_found: |-
-          Hmm, I don’t see a category in there anywhere. Note that `#` can't be the first character. Can you copy this in your next reply?
-
-          ```text
-          I can create a category link via #
-          ```
-        not_found_experimental: |-
           Hmm, I don’t see a category in there anywhere. Can you copy this in your next reply?
 
           ```text
diff --git a/plugins/discourse-narrative-bot/lib/discourse_narrative_bot/advanced_user_narrative.rb b/plugins/discourse-narrative-bot/lib/discourse_narrative_bot/advanced_user_narrative.rb
index 6fa8e6b6766..be66ba9ff77 100644
--- a/plugins/discourse-narrative-bot/lib/discourse_narrative_bot/advanced_user_narrative.rb
+++ b/plugins/discourse-narrative-bot/lib/discourse_narrative_bot/advanced_user_narrative.rb
@@ -39,27 +39,11 @@ module DiscourseNarrativeBot
         next_state: :tutorial_category_hashtag,
         next_instructions:
           Proc.new do
-            category = Category.secured(Guardian.new(@user)).last
-            slug = category.slug
-
-            if parent_category = category.parent_category
-              slug = "#{parent_category.slug}#{CategoryHashtag::SEPARATOR}#{slug}"
-            end
-
-            # TODO (martin) When enable_experimental_hashtag_autocomplete is the only option
-            # update the instructions and remove instructions_experimental, as well as the
-            # not_found translation
-            if SiteSetting.enable_experimental_hashtag_autocomplete
-              I18n.t(
-                "#{I18N_KEY}.category_hashtag.instructions_experimental",
-                i18n_post_args(category: "##{slug}"),
-              )
-            else
-              I18n.t(
-                "#{I18N_KEY}.category_hashtag.instructions",
-                i18n_post_args(category: "##{slug}"),
-              )
-            end
+            category = Category.secured(@user.guardian).last
+            I18n.t(
+              "#{I18N_KEY}.category_hashtag.instructions",
+              i18n_post_args(category: "##{category.slug_ref}"),
+            )
           end,
         recover: {
           action: :reply_to_recover,
@@ -298,9 +282,7 @@ module DiscourseNarrativeBot
       topic_id = @post.topic_id
       return unless valid_topic?(topic_id)
 
-      hashtag_css_class =
-        SiteSetting.enable_experimental_hashtag_autocomplete ? ".hashtag-cooked" : ".hashtag"
-      if Nokogiri::HTML5.fragment(@post.cooked).css(hashtag_css_class).size > 0
+      if Nokogiri::HTML5.fragment(@post.cooked).css(".hashtag-cooked").size > 0
         raw = <<~MD
           #{I18n.t("#{I18N_KEY}.category_hashtag.reply", i18n_post_args)}
 
@@ -312,14 +294,7 @@ module DiscourseNarrativeBot
       else
         fake_delay
         unless @data[:attempted]
-          if SiteSetting.enable_experimental_hashtag_autocomplete
-            reply_to(
-              @post,
-              I18n.t("#{I18N_KEY}.category_hashtag.not_found_experimental", i18n_post_args),
-            )
-          else
-            reply_to(@post, I18n.t("#{I18N_KEY}.category_hashtag.not_found", i18n_post_args))
-          end
+          reply_to(@post, I18n.t("#{I18N_KEY}.category_hashtag.not_found", i18n_post_args))
         end
         enqueue_timeout_job(@user)
         false
diff --git a/plugins/discourse-narrative-bot/spec/discourse_narrative_bot/advanced_user_narrative_spec.rb b/plugins/discourse-narrative-bot/spec/discourse_narrative_bot/advanced_user_narrative_spec.rb
index f391a9c8d23..4bf9bcc34fb 100644
--- a/plugins/discourse-narrative-bot/spec/discourse_narrative_bot/advanced_user_narrative_spec.rb
+++ b/plugins/discourse-narrative-bot/spec/discourse_narrative_bot/advanced_user_narrative_spec.rb
@@ -377,9 +377,6 @@ RSpec.describe DiscourseNarrativeBot::AdvancedUserNarrative do
 
         context "when reply contains the skip trigger" do
           it "should create the right reply" do
-            # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-            SiteSetting.enable_experimental_hashtag_autocomplete = false
-
             parent_category = Fabricate(:category, name: "a")
             _category = Fabricate(:category, parent_category: parent_category, name: "b")
 
@@ -417,9 +414,6 @@ RSpec.describe DiscourseNarrativeBot::AdvancedUserNarrative do
 
       context "when user recovers a post in the right topic" do
         it "should create the right reply" do
-          # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-          SiteSetting.enable_experimental_hashtag_autocomplete = false
-
           parent_category = Fabricate(:category, name: "a")
           _category = Fabricate(:category, parent_category: parent_category, name: "b")
           post
@@ -448,9 +442,6 @@ RSpec.describe DiscourseNarrativeBot::AdvancedUserNarrative do
           topic_id: topic.id,
           track: described_class.to_s,
         )
-
-        # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-        SiteSetting.enable_experimental_hashtag_autocomplete = false
       end
 
       context "when post is not in the right topic" do
@@ -509,37 +500,15 @@ RSpec.describe DiscourseNarrativeBot::AdvancedUserNarrative do
         narrative.input(:reply, user, post: post)
 
         expected_raw = <<~RAW
-          #{I18n.t("discourse_narrative_bot.advanced_user_narrative.category_hashtag.reply", base_uri: "")}
-
-          #{I18n.t("discourse_narrative_bot.advanced_user_narrative.change_topic_notification_level.instructions", base_uri: "")}
-        RAW
-
-        expect(Post.last.raw).to eq(expected_raw.chomp)
-        expect(narrative.get_data(user)[:state].to_sym).to eq(
-          :tutorial_change_topic_notification_level,
-        )
-      end
-
-      context "when enable_experimental_hashtag_autocomplete is true" do
-        before { SiteSetting.enable_experimental_hashtag_autocomplete = true }
-
-        it "should create the right reply" do
-          category = Fabricate(:category)
-
-          post.update!(raw: "Check out this ##{category.slug}")
-          narrative.input(:reply, user, post: post)
-
-          expected_raw = <<~RAW
             #{I18n.t("discourse_narrative_bot.advanced_user_narrative.category_hashtag.reply", base_uri: "")}
 
             #{I18n.t("discourse_narrative_bot.advanced_user_narrative.change_topic_notification_level.instructions", base_uri: "")}
           RAW
 
-          expect(Post.last.raw).to eq(expected_raw.chomp)
-          expect(narrative.get_data(user)[:state].to_sym).to eq(
-            :tutorial_change_topic_notification_level,
-          )
-        end
+        expect(Post.last.raw).to eq(expected_raw.chomp)
+        expect(narrative.get_data(user)[:state].to_sym).to eq(
+          :tutorial_change_topic_notification_level,
+        )
       end
     end
 
diff --git a/spec/integrity/common_mark_spec.rb b/spec/integrity/common_mark_spec.rb
index 85c8c821227..8f74ce313b4 100644
--- a/spec/integrity/common_mark_spec.rb
+++ b/spec/integrity/common_mark_spec.rb
@@ -5,9 +5,6 @@ RSpec.describe "CommonMark" do
     SiteSetting.enable_markdown_typographer = false
     SiteSetting.highlighted_languages = "ruby|aa"
 
-    # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-    SiteSetting.enable_experimental_hashtag_autocomplete = false
-
     html, state, md = nil
     failed = 0
 
@@ -34,7 +31,7 @@ RSpec.describe "CommonMark" do
           cooked = PrettyText.markdown(md, sanitize: false)
           cooked.strip!
           cooked.gsub!(" class=\"lang-auto\"", "")
-          cooked.gsub!(%r{<span class="hashtag">(.*)</span>}, "\\1")
+          cooked.gsub!(%r{<span class="hashtag-raw">(.*)</span>}, "\\1")
           cooked.gsub!(%r{<a name="(.*)" class="anchor" href="#\1*"></a>}, "")
           # we support data-attributes which is not in the spec
           cooked.gsub!("<pre data-code-startline=\"3\">", "<pre>")
diff --git a/spec/lib/concern/category_hashtag_spec.rb b/spec/lib/concern/category_hashtag_spec.rb
deleted file mode 100644
index 9a815653d5d..00000000000
--- a/spec/lib/concern/category_hashtag_spec.rb
+++ /dev/null
@@ -1,51 +0,0 @@
-# frozen_string_literal: true
-
-RSpec.describe CategoryHashtag do
-  describe "#query_from_hashtag_slug" do
-    fab!(:parent_category) { Fabricate(:category) }
-    fab!(:child_category) { Fabricate(:category, parent_category: parent_category) }
-
-    it "should return the right result for a parent category slug" do
-      expect(Category.query_from_hashtag_slug(parent_category.slug)).to eq(parent_category)
-    end
-
-    it "should return the right result for a parent and child category slug" do
-      expect(
-        Category.query_from_hashtag_slug(
-          "#{parent_category.slug}#{CategoryHashtag::SEPARATOR}#{child_category.slug}",
-        ),
-      ).to eq(child_category)
-    end
-
-    it "should return nil for incorrect parent category slug" do
-      expect(Category.query_from_hashtag_slug("random-slug")).to eq(nil)
-    end
-
-    it "should return nil for incorrect parent and child category slug" do
-      expect(
-        Category.query_from_hashtag_slug("random-slug#{CategoryHashtag::SEPARATOR}random-slug"),
-      ).to eq(nil)
-    end
-
-    it "should return nil for a non-existent root and a parent subcategory" do
-      expect(
-        Category.query_from_hashtag_slug(
-          "non-existent#{CategoryHashtag::SEPARATOR}#{parent_category.slug}",
-        ),
-      ).to eq(nil)
-    end
-
-    context "with multi-level categories" do
-      before { SiteSetting.max_category_nesting = 3 }
-
-      it "should return the right result for a grand child category slug" do
-        category = Fabricate(:category, parent_category: child_category)
-        expect(
-          Category.query_from_hashtag_slug(
-            "#{child_category.slug}#{CategoryHashtag::SEPARATOR}#{category.slug}",
-          ),
-        ).to eq(category)
-      end
-    end
-  end
-end
diff --git a/spec/lib/email/sender_spec.rb b/spec/lib/email/sender_spec.rb
index 2194b379ad0..b88f95712e5 100644
--- a/spec/lib/email/sender_spec.rb
+++ b/spec/lib/email/sender_spec.rb
@@ -566,7 +566,6 @@ RSpec.describe Email::Sender do
     end
 
     it "changes the hashtags to the slug with a # symbol beforehand rather than the full name of the resource" do
-      SiteSetting.enable_experimental_hashtag_autocomplete = true
       category = Fabricate(:category, slug: "dev")
       reply.update!(raw: reply.raw + "\n wow this is #dev")
       reply.rebake!
diff --git a/spec/lib/oneboxer_spec.rb b/spec/lib/oneboxer_spec.rb
index a3a68f5e414..8912b91adf2 100644
--- a/spec/lib/oneboxer_spec.rb
+++ b/spec/lib/oneboxer_spec.rb
@@ -179,7 +179,6 @@ RSpec.describe Oneboxer do
     end
 
     it "includes hashtag HTML" do
-      SiteSetting.enable_experimental_hashtag_autocomplete = true
       category = Fabricate(:category, slug: "random")
       tag = Fabricate(:tag, name: "bug")
       public_post = Fabricate(:post, raw: "This post has some hashtags, #random and #bug")
diff --git a/spec/lib/pretty_text/helpers_spec.rb b/spec/lib/pretty_text/helpers_spec.rb
index 0244da8a3b4..864c10c2463 100644
--- a/spec/lib/pretty_text/helpers_spec.rb
+++ b/spec/lib/pretty_text/helpers_spec.rb
@@ -16,37 +16,6 @@ RSpec.describe PrettyText::Helpers do
     end
   end
 
-  describe ".category_tag_hashtag_lookup" do
-    fab!(:tag) { Fabricate(:tag, name: "somecooltag") }
-    fab!(:category) do
-      Fabricate(:category, name: "Some Awesome Category", slug: "someawesomecategory")
-    end
-
-    it "handles tags based on slug with TAG_HASHTAG_POSTFIX" do
-      expect(
-        PrettyText::Helpers.category_tag_hashtag_lookup(
-          +"somecooltag#{PrettyText::Helpers::TAG_HASHTAG_POSTFIX}",
-        ),
-      ).to eq([tag.url, "somecooltag"])
-    end
-
-    it "handles categories based on slug" do
-      expect(PrettyText::Helpers.category_tag_hashtag_lookup("someawesomecategory")).to eq(
-        [category.url, "someawesomecategory"],
-      )
-    end
-
-    it "handles tags based on slug without TAG_HASHTAG_POSTFIX" do
-      expect(PrettyText::Helpers.category_tag_hashtag_lookup(+"somecooltag")).to eq(
-        [tag.url, "somecooltag"],
-      )
-    end
-
-    it "returns nil when no tag or category that matches exists" do
-      expect(PrettyText::Helpers.category_tag_hashtag_lookup("blah")).to eq(nil)
-    end
-  end
-
   describe ".hashtag_lookup" do
     fab!(:tag) { Fabricate(:tag, name: "somecooltag", description: "Coolest things ever") }
     fab!(:category) do
diff --git a/spec/lib/pretty_text_spec.rb b/spec/lib/pretty_text_spec.rb
index df6fc039632..19def8b7df0 100644
--- a/spec/lib/pretty_text_spec.rb
+++ b/spec/lib/pretty_text_spec.rb
@@ -1722,50 +1722,6 @@ RSpec.describe PrettyText do
   end
 
   it "produces hashtag links" do
-    # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-    SiteSetting.enable_experimental_hashtag_autocomplete = false
-
-    category = Fabricate(:category, name: "testing")
-    category2 = Fabricate(:category, name: "known")
-    Fabricate(:topic, tags: [Fabricate(:tag, name: "known")])
-
-    cooked = PrettyText.cook(" #unknown::tag #known #known::tag #testing")
-
-    [
-      "<span class=\"hashtag\">#unknown::tag</span>",
-      "<a class=\"hashtag\" href=\"#{category2.url}\">#<span>known</span></a>",
-      "<a class=\"hashtag\" href=\"/tag/known\">#<span>known</span></a>",
-      "<a class=\"hashtag\" href=\"#{category.url}\">#<span>testing</span></a>",
-    ].each { |element| expect(cooked).to include(element) }
-
-    cooked = PrettyText.cook("[`a` #known::tag here](http://example.com)")
-
-    html = <<~HTML
-      <p><a href="http://example.com" rel="noopener nofollow ugc"><code>a</code> #known::tag here</a></p>
-    HTML
-
-    expect(cooked).to eq(html.strip)
-
-    cooked = PrettyText.cook("<a href='http://example.com'>`a` #known::tag here</a>")
-
-    expect(cooked).to eq(html.strip)
-
-    cooked = PrettyText.cook("<A href='/a'>test</A> #known::tag")
-    html = <<~HTML
-      <p><a href="/a">test</a> <a class="hashtag" href="/tag/known">#<span>known</span></a></p>
-    HTML
-
-    expect(cooked).to eq(html.strip)
-
-    # ensure it does not fight with the autolinker
-    expect(PrettyText.cook(" http://somewhere.com/#known")).not_to include("hashtag")
-    expect(PrettyText.cook(" http://somewhere.com/?#known")).not_to include("hashtag")
-    expect(PrettyText.cook(" http://somewhere.com/?abc#known")).not_to include("hashtag")
-  end
-
-  it "produces hashtag links when enable_experimental_hashtag_autocomplete is enabled" do
-    SiteSetting.enable_experimental_hashtag_autocomplete = true
-
     user = Fabricate(:user)
     category = Fabricate(:category, name: "testing", slug: "testing")
     category2 = Fabricate(:category, name: "known", slug: "known")
@@ -2059,11 +2015,8 @@ HTML
     end
 
     it "does not replace hashtags and mentions" do
-      # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-      SiteSetting.enable_experimental_hashtag_autocomplete = false
-
       Fabricate(:user, username: "test")
-      category = Fabricate(:category, slug: "test")
+      category = Fabricate(:category, slug: "test", name: "test")
       Fabricate(
         :watched_word,
         action: WatchedWord.actions[:replace],
@@ -2071,19 +2024,25 @@ HTML
         replacement: "discourse",
       )
 
-      expect(PrettyText.cook("@test #test test")).to match_html(<<~HTML)
-        <p>
-          <a class="mention" href="/u/test">@test</a>
-          <a class="hashtag" href="/c/test/#{category.id}">#<span>test</span></a>
-          discourse
-        </p>
-      HTML
+      cooked = PrettyText.cook("@test #test test")
+      expect(cooked).to have_tag("a", text: "@test", with: { class: "mention", href: "/u/test" })
+      expect(cooked).to have_tag(
+        "a",
+        text: "test",
+        with: {
+          class: "hashtag-cooked",
+          href: "/c/test/#{category.id}",
+          "data-type": "category",
+          "data-slug": category.slug,
+          "data-id": category.id,
+        },
+      ) do
+        with_tag("span", with: { class: "hashtag-icon-placeholder" })
+      end
+      expect(cooked).to include("discourse")
     end
 
     it "does not replace hashtags and mentions when watched words are regular expressions" do
-      # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-      SiteSetting.enable_experimental_hashtag_autocomplete = false
-
       SiteSetting.watched_words_regular_expressions = true
 
       Fabricate(:user, username: "test")
@@ -2095,19 +2054,6 @@ HTML
         replacement: "discourse",
       )
 
-      cooked = PrettyText.cook("@test #test test")
-      expect(cooked).to have_tag("a", text: "@test", with: { class: "mention", href: "/u/test" })
-      expect(cooked).to have_tag(
-        "a",
-        text: "#test",
-        with: {
-          class: "hashtag",
-          href: "/c/test/#{category.id}",
-        },
-      )
-      expect(cooked).to include("tdiscourset")
-
-      SiteSetting.enable_experimental_hashtag_autocomplete = true
       cooked = PrettyText.cook("@test #test test")
       expect(cooked).to have_tag("a", text: "@test", with: { class: "mention", href: "/u/test" })
       expect(cooked).to have_tag(
diff --git a/spec/models/category_spec.rb b/spec/models/category_spec.rb
index 26c7eeea7af..e540433aee9 100644
--- a/spec/models/category_spec.rb
+++ b/spec/models/category_spec.rb
@@ -1451,4 +1451,37 @@ RSpec.describe Category do
       end
     end
   end
+
+  describe "#slug_ref" do
+    fab!(:category) { Fabricate(:category, slug: "foo") }
+
+    it "returns the slug for categories without parents" do
+      expect(category.slug_ref).to eq("foo")
+    end
+
+    context "for category with parent" do
+      fab!(:subcategory) { Fabricate(:category, parent_category: category, slug: "bar") }
+
+      it "returns the parent and child slug ref with separator" do
+        expect(subcategory.slug_ref).to eq("foo#{Category::SLUG_REF_SEPARATOR}bar")
+      end
+    end
+
+    context "for category with multiple parents" do
+      let(:subcategory_1) { Fabricate(:category, parent_category: category, slug: "bar") }
+      let(:subcategory_2) { Fabricate(:category, parent_category: subcategory_1, slug: "boo") }
+
+      before { SiteSetting.max_category_nesting = 3 }
+
+      it "returns the parent and child slug ref with separator" do
+        expect(subcategory_2.slug_ref(depth: 2)).to eq(
+          "foo#{Category::SLUG_REF_SEPARATOR}bar#{Category::SLUG_REF_SEPARATOR}boo",
+        )
+      end
+
+      it "allows limiting depth" do
+        expect(subcategory_2.slug_ref(depth: 1)).to eq("bar#{Category::SLUG_REF_SEPARATOR}boo")
+      end
+    end
+  end
 end
diff --git a/spec/requests/hashtags_controller_spec.rb b/spec/requests/hashtags_controller_spec.rb
index 98b37199a10..f17a8eeb4d7 100644
--- a/spec/requests/hashtags_controller_spec.rb
+++ b/spec/requests/hashtags_controller_spec.rb
@@ -20,305 +20,184 @@ RSpec.describe HashtagsController do
   end
 
   describe "#lookup" do
-    context "when enable_experimental_hashtag_autocomplete disabled" do
-      # TODO (martin) Remove when enable_experimental_hashtag_autocomplete is default for all sites
-      before { SiteSetting.enable_experimental_hashtag_autocomplete = false }
-      context "when logged in" do
-        context "as regular user" do
-          before { sign_in(Fabricate(:user)) }
+    context "when logged in" do
+      context "as regular user" do
+        before { sign_in(Fabricate(:user)) }
 
-          it "returns only valid categories and tags" do
-            get "/hashtags.json",
-                params: {
-                  slugs: [category.slug, private_category.slug, "none", tag.name, hidden_tag.name],
-                }
+        it "returns only valid categories and tags" do
+          get "/hashtags.json",
+              params: {
+                slugs: [category.slug, private_category.slug, "none", tag.name, hidden_tag.name],
+                order: %w[category tag],
+              }
 
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq(
-              "categories" => {
-                category.slug => category.url,
-              },
-              "tags" => {
-                tag.name => tag.full_url,
-              },
-            )
-          end
-
-          it "handles tags with the TAG_HASHTAG_POSTFIX" do
-            get "/hashtags.json",
-                params: {
-                  slugs: ["#{tag.name}#{PrettyText::Helpers::TAG_HASHTAG_POSTFIX}"],
-                }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq(
-              "categories" => {
-              },
-              "tags" => {
-                tag.name => tag.full_url,
-              },
-            )
-          end
-
-          it "does not return restricted categories or hidden tags" do
-            get "/hashtags.json", params: { slugs: [private_category.slug, hidden_tag.name] }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq("categories" => {}, "tags" => {})
-          end
+          expect(response.status).to eq(200)
+          expect(response.parsed_body).to eq(
+            {
+              "category" => [
+                {
+                  "relative_url" => category.url,
+                  "text" => category.name,
+                  "description" => nil,
+                  "icon" => "folder",
+                  "type" => "category",
+                  "ref" => category.slug,
+                  "slug" => category.slug,
+                  "id" => category.id,
+                },
+              ],
+              "tag" => [
+                {
+                  "relative_url" => tag.url,
+                  "text" => tag.name,
+                  "description" => nil,
+                  "icon" => "tag",
+                  "type" => "tag",
+                  "ref" => tag.name,
+                  "slug" => tag.name,
+                  "secondary_text" => "x0",
+                  "id" => tag.id,
+                },
+              ],
+            },
+          )
         end
 
-        context "as admin" do
-          fab!(:admin) { Fabricate(:admin) }
+        it "handles tags with the ::tag type suffix" do
+          get "/hashtags.json", params: { slugs: ["#{tag.name}::tag"], order: %w[category tag] }
 
-          before { sign_in(admin) }
-
-          it "returns restricted categories and hidden tags" do
-            group.add(admin)
-
-            get "/hashtags.json", params: { slugs: [private_category.slug, hidden_tag.name] }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq(
-              "categories" => {
-                private_category.slug => private_category.url,
-              },
-              "tags" => {
-                hidden_tag.name => hidden_tag.full_url,
-              },
-            )
-          end
+          expect(response.status).to eq(200)
+          expect(response.parsed_body).to eq(
+            {
+              "category" => [],
+              "tag" => [
+                {
+                  "relative_url" => tag.url,
+                  "text" => tag.name,
+                  "description" => nil,
+                  "icon" => "tag",
+                  "type" => "tag",
+                  "ref" => "#{tag.name}::tag",
+                  "slug" => tag.name,
+                  "secondary_text" => "x0",
+                  "id" => tag.id,
+                },
+              ],
+            },
+          )
         end
 
-        context "with sub-sub-categories" do
-          before do
-            SiteSetting.max_category_nesting = 3
-            sign_in(Fabricate(:user))
-          end
+        it "does not return restricted categories or hidden tags" do
+          get "/hashtags.json",
+              params: {
+                slugs: [private_category.slug, hidden_tag.name],
+                order: %w[category tag],
+              }
 
-          it "works" do
-            foo = Fabricate(:category_with_definition, slug: "foo")
-            foobar = Fabricate(:category_with_definition, slug: "bar", parent_category_id: foo.id)
-            foobarbaz =
-              Fabricate(:category_with_definition, slug: "baz", parent_category_id: foobar.id)
-
-            qux = Fabricate(:category_with_definition, slug: "qux")
-            quxbar = Fabricate(:category_with_definition, slug: "bar", parent_category_id: qux.id)
-            quxbarbaz =
-              Fabricate(:category_with_definition, slug: "baz", parent_category_id: quxbar.id)
-
-            invalid_slugs = [":"]
-            child_slugs = %w[bar baz]
-            deeply_nested_slugs = %w[foo:bar:baz qux:bar:baz]
-            get "/hashtags.json",
-                params: {
-                  slugs:
-                    invalid_slugs + child_slugs + deeply_nested_slugs +
-                      %w[foo foo:bar bar:baz qux qux:bar],
-                }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body["categories"]).to eq(
-              "foo" => foo.url,
-              "foo:bar" => foobar.url,
-              "bar:baz" => foobarbaz.id < quxbarbaz.id ? foobarbaz.url : quxbarbaz.url,
-              "qux" => qux.url,
-              "qux:bar" => quxbar.url,
-            )
-          end
+          expect(response.status).to eq(200)
+          expect(response.parsed_body).to eq({ "category" => [], "tag" => [] })
         end
       end
 
-      context "when not logged in" do
-        it "returns invalid access" do
-          get "/hashtags.json", params: { slugs: [] }
-          expect(response.status).to eq(403)
+      context "as admin" do
+        fab!(:admin) { Fabricate(:admin) }
+
+        before { sign_in(admin) }
+
+        it "returns restricted categories and hidden tags" do
+          group.add(admin)
+
+          get "/hashtags.json",
+              params: {
+                slugs: [private_category.slug, hidden_tag.name],
+                order: %w[category tag],
+              }
+
+          expect(response.status).to eq(200)
+          expect(response.parsed_body).to eq(
+            {
+              "category" => [
+                {
+                  "relative_url" => private_category.url,
+                  "text" => private_category.name,
+                  "description" => nil,
+                  "icon" => "folder",
+                  "type" => "category",
+                  "ref" => private_category.slug,
+                  "slug" => private_category.slug,
+                  "id" => private_category.id,
+                },
+              ],
+              "tag" => [
+                {
+                  "relative_url" => hidden_tag.url,
+                  "text" => hidden_tag.name,
+                  "description" => nil,
+                  "icon" => "tag",
+                  "type" => "tag",
+                  "ref" => hidden_tag.name,
+                  "slug" => hidden_tag.name,
+                  "secondary_text" => "x0",
+                  "id" => hidden_tag.id,
+                },
+              ],
+            },
+          )
+        end
+      end
+
+      context "with sub-sub-categories" do
+        before do
+          SiteSetting.max_category_nesting = 3
+          sign_in(Fabricate(:user))
+        end
+
+        it "works" do
+          foo = Fabricate(:category_with_definition, slug: "foo")
+          foobar = Fabricate(:category_with_definition, slug: "bar", parent_category_id: foo.id)
+          foobarbaz =
+            Fabricate(:category_with_definition, slug: "baz", parent_category_id: foobar.id)
+
+          qux = Fabricate(:category_with_definition, slug: "qux")
+          quxbar = Fabricate(:category_with_definition, slug: "bar", parent_category_id: qux.id)
+          quxbarbaz =
+            Fabricate(:category_with_definition, slug: "baz", parent_category_id: quxbar.id)
+
+          invalid_slugs = [":"]
+          child_slugs = %w[bar baz]
+          deeply_nested_slugs = %w[foo:bar:baz qux:bar:baz]
+          get "/hashtags.json",
+              params: {
+                slugs:
+                  invalid_slugs + child_slugs + deeply_nested_slugs +
+                    %w[foo foo:bar bar:baz qux qux:bar],
+                order: %w[category tag],
+              }
+
+          expect(response.status).to eq(200)
+          found_categories = response.parsed_body["category"]
+          expect(found_categories.map { |c| c["ref"] }).to match_array(
+            %w[foo foo:bar bar:baz qux qux:bar],
+          )
+          expect(found_categories.find { |c| c["ref"] == "foo" }["relative_url"]).to eq(foo.url)
+          expect(found_categories.find { |c| c["ref"] == "foo:bar" }["relative_url"]).to eq(
+            foobar.url,
+          )
+          expect(found_categories.find { |c| c["ref"] == "bar:baz" }["relative_url"]).to eq(
+            foobarbaz.url,
+          )
+          expect(found_categories.find { |c| c["ref"] == "qux" }["relative_url"]).to eq(qux.url)
+          expect(found_categories.find { |c| c["ref"] == "qux:bar" }["relative_url"]).to eq(
+            quxbar.url,
+          )
         end
       end
     end
 
-    context "when enable_experimental_hashtag_autocomplete enabled" do
-      before { SiteSetting.enable_experimental_hashtag_autocomplete = true }
-
-      context "when logged in" do
-        context "as regular user" do
-          before { sign_in(Fabricate(:user)) }
-
-          it "returns only valid categories and tags" do
-            get "/hashtags.json",
-                params: {
-                  slugs: [category.slug, private_category.slug, "none", tag.name, hidden_tag.name],
-                  order: %w[category tag],
-                }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq(
-              {
-                "category" => [
-                  {
-                    "relative_url" => category.url,
-                    "text" => category.name,
-                    "description" => nil,
-                    "icon" => "folder",
-                    "type" => "category",
-                    "ref" => category.slug,
-                    "slug" => category.slug,
-                    "id" => category.id,
-                  },
-                ],
-                "tag" => [
-                  {
-                    "relative_url" => tag.url,
-                    "text" => tag.name,
-                    "description" => nil,
-                    "icon" => "tag",
-                    "type" => "tag",
-                    "ref" => tag.name,
-                    "slug" => tag.name,
-                    "secondary_text" => "x0",
-                    "id" => tag.id,
-                  },
-                ],
-              },
-            )
-          end
-
-          it "handles tags with the ::tag type suffix" do
-            get "/hashtags.json", params: { slugs: ["#{tag.name}::tag"], order: %w[category tag] }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq(
-              {
-                "category" => [],
-                "tag" => [
-                  {
-                    "relative_url" => tag.url,
-                    "text" => tag.name,
-                    "description" => nil,
-                    "icon" => "tag",
-                    "type" => "tag",
-                    "ref" => "#{tag.name}::tag",
-                    "slug" => tag.name,
-                    "secondary_text" => "x0",
-                    "id" => tag.id,
-                  },
-                ],
-              },
-            )
-          end
-
-          it "does not return restricted categories or hidden tags" do
-            get "/hashtags.json",
-                params: {
-                  slugs: [private_category.slug, hidden_tag.name],
-                  order: %w[category tag],
-                }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq({ "category" => [], "tag" => [] })
-          end
-        end
-
-        context "as admin" do
-          fab!(:admin) { Fabricate(:admin) }
-
-          before { sign_in(admin) }
-
-          it "returns restricted categories and hidden tags" do
-            group.add(admin)
-
-            get "/hashtags.json",
-                params: {
-                  slugs: [private_category.slug, hidden_tag.name],
-                  order: %w[category tag],
-                }
-
-            expect(response.status).to eq(200)
-            expect(response.parsed_body).to eq(
-              {
-                "category" => [
-                  {
-                    "relative_url" => private_category.url,
-                    "text" => private_category.name,
-                    "description" => nil,
-                    "icon" => "folder",
-                    "type" => "category",
-                    "ref" => private_category.slug,
-                    "slug" => private_category.slug,
-                    "id" => private_category.id,
-                  },
-                ],
-                "tag" => [
-                  {
-                    "relative_url" => hidden_tag.url,
-                    "text" => hidden_tag.name,
-                    "description" => nil,
-                    "icon" => "tag",
-                    "type" => "tag",
-                    "ref" => hidden_tag.name,
-                    "slug" => hidden_tag.name,
-                    "secondary_text" => "x0",
-                    "id" => hidden_tag.id,
-                  },
-                ],
-              },
-            )
-          end
-        end
-
-        context "with sub-sub-categories" do
-          before do
-            SiteSetting.max_category_nesting = 3
-            sign_in(Fabricate(:user))
-          end
-
-          it "works" do
-            foo = Fabricate(:category_with_definition, slug: "foo")
-            foobar = Fabricate(:category_with_definition, slug: "bar", parent_category_id: foo.id)
-            foobarbaz =
-              Fabricate(:category_with_definition, slug: "baz", parent_category_id: foobar.id)
-
-            qux = Fabricate(:category_with_definition, slug: "qux")
-            quxbar = Fabricate(:category_with_definition, slug: "bar", parent_category_id: qux.id)
-            quxbarbaz =
-              Fabricate(:category_with_definition, slug: "baz", parent_category_id: quxbar.id)
-
-            invalid_slugs = [":"]
-            child_slugs = %w[bar baz]
-            deeply_nested_slugs = %w[foo:bar:baz qux:bar:baz]
-            get "/hashtags.json",
-                params: {
-                  slugs:
-                    invalid_slugs + child_slugs + deeply_nested_slugs +
-                      %w[foo foo:bar bar:baz qux qux:bar],
-                  order: %w[category tag],
-                }
-
-            expect(response.status).to eq(200)
-            found_categories = response.parsed_body["category"]
-            expect(found_categories.map { |c| c["ref"] }).to match_array(
-              %w[foo foo:bar bar:baz qux qux:bar],
-            )
-            expect(found_categories.find { |c| c["ref"] == "foo" }["relative_url"]).to eq(foo.url)
-            expect(found_categories.find { |c| c["ref"] == "foo:bar" }["relative_url"]).to eq(
-              foobar.url,
-            )
-            expect(found_categories.find { |c| c["ref"] == "bar:baz" }["relative_url"]).to eq(
-              foobarbaz.url,
-            )
-            expect(found_categories.find { |c| c["ref"] == "qux" }["relative_url"]).to eq(qux.url)
-            expect(found_categories.find { |c| c["ref"] == "qux:bar" }["relative_url"]).to eq(
-              quxbar.url,
-            )
-          end
-        end
-      end
-
-      context "when not logged in" do
-        it "returns invalid access" do
-          get "/hashtags.json", params: { slugs: [], order: %w[category tag] }
-          expect(response.status).to eq(403)
-        end
+    context "when not logged in" do
+      it "returns invalid access" do
+        get "/hashtags.json", params: { slugs: [], order: %w[category tag] }
+        expect(response.status).to eq(403)
       end
     end
   end
diff --git a/spec/services/hashtag_autocomplete_service_spec.rb b/spec/services/hashtag_autocomplete_service_spec.rb
index 6419472a2bc..ed3d1960c3b 100644
--- a/spec/services/hashtag_autocomplete_service_spec.rb
+++ b/spec/services/hashtag_autocomplete_service_spec.rb
@@ -313,53 +313,6 @@ RSpec.describe HashtagAutocompleteService do
     end
   end
 
-  describe "#lookup_old" do
-    fab!(:tag2) { Fabricate(:tag, name: "fiction-books") }
-
-    it "returns categories and tags in a hash format with the slug and url" do
-      result = service.lookup_old(%w[the-book-club great-books fiction-books])
-      expect(result[:categories]).to eq({ "the-book-club" => "/c/the-book-club/#{category1.id}" })
-      expect(result[:tags]).to eq(
-        {
-          "fiction-books" => "http://test.localhost/tag/fiction-books",
-          "great-books" => "http://test.localhost/tag/great-books",
-        },
-      )
-    end
-
-    it "does not include categories the user cannot access" do
-      category1.update!(read_restricted: true)
-      result = service.lookup_old(%w[the-book-club great-books fiction-books])
-      expect(result[:categories]).to eq({})
-    end
-
-    it "does not include tags the user cannot access" do
-      Fabricate(:tag_group, permissions: { "staff" => 1 }, tag_names: ["great-books"])
-      result = service.lookup_old(%w[the-book-club great-books fiction-books])
-      expect(result[:tags]).to eq({ "fiction-books" => "http://test.localhost/tag/fiction-books" })
-    end
-
-    it "handles tags which have the ::tag suffix" do
-      result = service.lookup_old(%w[the-book-club great-books::tag fiction-books])
-      expect(result[:tags]).to eq(
-        {
-          "fiction-books" => "http://test.localhost/tag/fiction-books",
-          "great-books" => "http://test.localhost/tag/great-books",
-        },
-      )
-    end
-
-    context "when not tagging_enabled" do
-      before { SiteSetting.tagging_enabled = false }
-
-      it "does not return tags" do
-        result = service.lookup_old(%w[the-book-club great-books fiction-books])
-        expect(result[:categories]).to eq({ "the-book-club" => "/c/the-book-club/#{category1.id}" })
-        expect(result[:tags]).to eq({})
-      end
-    end
-  end
-
   describe "#lookup" do
     fab!(:tag2) { Fabricate(:tag, name: "fiction-books") }
 
diff --git a/spec/services/post_alerter_spec.rb b/spec/services/post_alerter_spec.rb
index fe403d31d4a..18f7295f1b3 100644
--- a/spec/services/post_alerter_spec.rb
+++ b/spec/services/post_alerter_spec.rb
@@ -1332,8 +1332,7 @@ RSpec.describe PostAlerter do
       expect(JSON.parse(body)).to eq(payload)
     end
 
-    it "does not have invalid HTML in the excerpt when enable_experimental_hashtag_autocomplete is enabled" do
-      SiteSetting.enable_experimental_hashtag_autocomplete = true
+    it "does not have invalid HTML in the excerpt" do
       Fabricate(:category, slug: "random")
       Jobs.run_immediately!
       body = nil
diff --git a/spec/system/hashtag_autocomplete_spec.rb b/spec/system/hashtag_autocomplete_spec.rb
index 960ac099cdd..ef79c2d13e0 100644
--- a/spec/system/hashtag_autocomplete_spec.rb
+++ b/spec/system/hashtag_autocomplete_spec.rb
@@ -2,7 +2,7 @@
 
 describe "Using #hashtag autocompletion to search for and lookup categories and tags",
          type: :system do
-  fab!(:user) { Fabricate(:user) }
+  fab!(:current_user) { Fabricate(:user) }
   fab!(:category) do
     Fabricate(:category, name: "Cool Category", slug: "cool-cat", topic_count: 3234)
   end
@@ -16,10 +16,7 @@ describe "Using #hashtag autocompletion to search for and lookup categories and
   let(:uncategorized_category) { Category.find(SiteSetting.uncategorized_category_id) }
   let(:topic_page) { PageObjects::Pages::Topic.new }
 
-  before do
-    SiteSetting.enable_experimental_hashtag_autocomplete = true
-    sign_in user
-  end
+  before { sign_in(current_user) }
 
   def visit_topic_and_initiate_autocomplete(initiation_text: "something #co", expected_count: 2)
     topic_page.visit_topic_and_open_composer(topic)
diff --git a/spec/tasks/hashtags_spec.rb b/spec/tasks/hashtags_spec.rb
index 679f3e0e563..ac70bac1e49 100644
--- a/spec/tasks/hashtags_spec.rb
+++ b/spec/tasks/hashtags_spec.rb
@@ -9,9 +9,8 @@ RSpec.describe "tasks/hashtags" do
   describe "hashtag:mark_old_format_for_rebake" do
     fab!(:category) { Fabricate(:category, slug: "support") }
 
-    before { SiteSetting.enable_experimental_hashtag_autocomplete = false }
-
     it "sets the baked_version to 0 for matching posts" do
+      hashtag_html = PrettyText.cook("#support").gsub("<p>", "").gsub("</p>", "")
       post_1 = Fabricate(:post, raw: "This is a cool #support hashtag")
       post_2 =
         Fabricate(
@@ -19,10 +18,12 @@ RSpec.describe "tasks/hashtags" do
           raw:
             "Some other thing which will not match <a class=\"hashtag-wow\">some weird custom thing</a>",
         )
-
-      SiteSetting.enable_experimental_hashtag_autocomplete = true
       post_3 = Fabricate(:post, raw: "This is a cool #support hashtag")
-      SiteSetting.enable_experimental_hashtag_autocomplete = false
+
+      # Update to use the old hashtag format.
+      post_1.update!(
+        cooked: post_1.cooked.gsub(hashtag_html, "<span class=\"hashtag\"'>#support</span>"),
+      )
 
       capture_stdout { Rake::Task["hashtags:mark_old_format_for_rebake"].invoke }