DEV: Support colocation under `/admin` namespace in themes/plugins (#19353)

app/assets/javascripts/discourse-plugins/colocated-template-compiler.js

@@ -3,12 +3,12 @@ const ColocatedTemplateProcessor = require("ember-cli-htmlbars/lib/colocated-bro
 module.exports = class DiscoursePluginColocatedTemplateProcessor extends (
   ColocatedTemplateProcessor
 ) {
-  constructor(tree, discoursePluginName) {
+  constructor(tree, rootName) {
     super(tree);
-    this.discoursePluginName = discoursePluginName;
+    this.rootName = rootName;
   }
 
   detectRootName() {
-    return `discourse/plugins/${this.discoursePluginName}/discourse`;
+    return this.rootName;
   }
 };

app/assets/javascripts/discourse-plugins/index.js

@@ -176,7 +176,15 @@ module.exports = {
 
     tree = RawHandlebarsCompiler(tree);
 
-    tree = new DiscoursePluginColocatedTemplateProcessor(tree, pluginName);
+    const colocateBase = `discourse/plugins/${pluginName}`;
+    tree = new DiscoursePluginColocatedTemplateProcessor(
+      tree,
+      `${colocateBase}/discourse`
+    );
+    tree = new DiscoursePluginColocatedTemplateProcessor(
+      tree,
+      `${colocateBase}/admin`
+    );
     tree = this.compileTemplates(tree);
 
     tree = this.processedAddonJsFiles(tree);

lib/theme_javascript_compiler.rb

@@ -89,8 +89,6 @@ class ThemeJavascriptCompiler
   end
 
   def append_tree(tree, for_tests: false)
-    root_name = "discourse"
-
     # Replace legacy extensions
     tree.transform_keys! do |filename|
       if filename.ends_with? ".js.es6"
@@ -121,7 +119,7 @@ class ThemeJavascriptCompiler
 
     # Handle colocated components
     tree.dup.each_pair do |filename, content|
-      is_component_template = filename.end_with?(".hbs") && filename.start_with?("#{root_name}/components/")
+      is_component_template = filename.end_with?(".hbs") && filename.start_with?("discourse/components/", "admin/components/")
       next if !is_component_template
       template_contents = content
 

spec/lib/theme_javascript_compiler_spec.rb

@@ -110,6 +110,20 @@ RSpec.describe ThemeJavascriptCompiler do
       expect(compiler.raw_content).to include("setComponentTemplate")
     end
 
+    it "handles colocated admin components" do
+      compiler.append_tree(
+        {
+          "admin/components/mycomponent.js" => <<~JS,
+            import Component from "@glimmer/component";
+            export default class MyComponent extends Component {}
+          JS
+          "admin/components/mycomponent.hbs" => "{{my-component-template}}"
+        }
+      )
+      expect(compiler.raw_content).to include("__COLOCATED_TEMPLATE__ =")
+      expect(compiler.raw_content).to include("setComponentTemplate")
+    end
+
     it "applies theme AST transforms to colocated components" do
       compiler = ThemeJavascriptCompiler.new(12345678910, 'my theme name')
       compiler.append_tree(