From e28a201b9ccfb16f93089cea9207fca9b552d98c Mon Sep 17 00:00:00 2001
From: Godfrey Chan <godfreykfc@gmail.com>
Date: Mon, 24 May 2021 23:33:40 -0700
Subject: [PATCH] [BUGFIX release] Improve class based tranform deprecation
 message

---
 .../lib/system/compile-options.ts             | 30 +++++++++++--------
 .../tests/system/compile_options_test.js      |  6 ++--
 2 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/packages/ember-template-compiler/lib/system/compile-options.ts b/packages/ember-template-compiler/lib/system/compile-options.ts
index 1f4c3e67964..87832571e09 100644
--- a/packages/ember-template-compiler/lib/system/compile-options.ts
+++ b/packages/ember-template-compiler/lib/system/compile-options.ts
@@ -82,11 +82,16 @@ interface LegacyPlugin {
 
 export type LegacyPluginClass = new (env: ASTPluginEnvironment) => LegacyPlugin;
 
-function wrapLegacyPluginIfNeeded(_plugin: PluginFunc | LegacyPluginClass): PluginFunc {
-  let plugin = _plugin;
-  if (_plugin.prototype && _plugin.prototype.transform) {
+function isLegacyPluginClass(plugin: PluginFunc | LegacyPluginClass): plugin is LegacyPluginClass {
+  return plugin.prototype && typeof plugin.prototype.transform === 'function';
+}
+
+function wrapLegacyPluginIfNeeded(plugin: PluginFunc | LegacyPluginClass): PluginFunc {
+  if (isLegacyPluginClass(plugin)) {
+    const Plugin = plugin;
+
     deprecate(
-      'Using class based template compilation plugins is deprecated, please update to the functional style',
+      `Using class based template compilation plugins is deprecated, please update to the functional style: ${Plugin.name}`,
       false,
       {
         id: 'template-compiler.registerPlugin',
@@ -102,28 +107,29 @@ function wrapLegacyPluginIfNeeded(_plugin: PluginFunc | LegacyPluginClass): Plug
       let pluginInstantiated = false;
 
       return {
-        name: _plugin.constructor && _plugin.constructor.name,
+        name: plugin.name,
 
         visitor: {
           Program(node: AST.Program): AST.Node | void {
             if (!pluginInstantiated) {
               pluginInstantiated = true;
-              let plugin = new (_plugin as LegacyPluginClass)(env);
+              let instance = new Plugin(env);
 
-              plugin.syntax = env.syntax;
+              instance.syntax = env.syntax;
 
-              return plugin.transform(node);
+              return instance.transform(node);
             }
           },
         },
       };
     };
 
-    pluginFunc.__raw = _plugin as LegacyPluginClass;
-    plugin = pluginFunc;
-  }
+    pluginFunc.__raw = Plugin;
 
-  return plugin as PluginFunc;
+    return pluginFunc;
+  } else {
+    return plugin;
+  }
 }
 
 export function registerPlugin(type: string, _plugin: PluginFunc | LegacyPluginClass): void {
diff --git a/packages/ember-template-compiler/tests/system/compile_options_test.js b/packages/ember-template-compiler/tests/system/compile_options_test.js
index 921d3f2387a..2b75b69f36d 100644
--- a/packages/ember-template-compiler/tests/system/compile_options_test.js
+++ b/packages/ember-template-compiler/tests/system/compile_options_test.js
@@ -124,7 +124,7 @@ moduleFor(
   class extends CustomPluginsTests {
     beforeEach() {
       expectDeprecation(
-        'Using class based template compilation plugins is deprecated, please update to the functional style'
+        `Using class based template compilation plugins is deprecated, please update to the functional style: ${LegacyCustomTransform.name}`
       );
       expectDeprecation(
         'registerPlugin is deprecated, please pass plugins directly via `compile` and/or `precompile`.'
@@ -141,7 +141,7 @@ moduleFor(
 
     ['@test custom registered plugins are deduplicated'](assert) {
       expectDeprecation(
-        'Using class based template compilation plugins is deprecated, please update to the functional style'
+        `Using class based template compilation plugins is deprecated, please update to the functional style: ${LegacyCustomTransform.name}`
       );
       expectDeprecation(
         'registerPlugin is deprecated, please pass plugins directly via `compile` and/or `precompile`.'
@@ -194,7 +194,7 @@ moduleFor(
     // override so that we can provide custom AST plugins to compile
     compile(templateString) {
       expectDeprecation(
-        'Using class based template compilation plugins is deprecated, please update to the functional style'
+        'Using class based template compilation plugins is deprecated, please update to the functional style: LegacyCustomTransform'
       );
       return compile(templateString, {
         plugins: {