From 5d346a2fa99b295c7aef6042d4f05bb2df4972b2 Mon Sep 17 00:00:00 2001
From: NullVoxPopuli <199018+NullVoxPopuli@users.noreply.github.com>
Date: Thu, 19 Feb 2026 16:29:45 -0500
Subject: [PATCH] Extract rule: template-no-action

---
 README.md                             |  1 +
 docs/rules/template-no-action.md      | 54 +++++++++++++++++++++
 lib/rules/template-no-action.js       | 70 +++++++++++++++++++++++++++
 tests/lib/rules/template-no-action.js | 61 +++++++++++++++++++++++
 4 files changed, 186 insertions(+)
 create mode 100644 docs/rules/template-no-action.md
 create mode 100644 lib/rules/template-no-action.js
 create mode 100644 tests/lib/rules/template-no-action.js

diff --git a/README.md b/README.md
index 118014a552..fd7a909acf 100644
--- a/README.md
+++ b/README.md
@@ -247,6 +247,7 @@ rules in templates can be disabled with eslint directives with mustache or html
 | [no-observers](docs/rules/no-observers.md)                                                       | disallow usage of observers                               | ✅  |    |    |
 | [no-old-shims](docs/rules/no-old-shims.md)                                                       | disallow usage of old shims for modules                   | ✅  | 🔧 |    |
 | [no-string-prototype-extensions](docs/rules/no-string-prototype-extensions.md)                   | disallow usage of `String` prototype extensions           | ✅  |    |    |
+| [template-no-action](docs/rules/template-no-action.md)                                           | disallow {{action}} helper                                |    |    |    |
 
 ### Ember Data
 
diff --git a/docs/rules/template-no-action.md b/docs/rules/template-no-action.md
new file mode 100644
index 0000000000..3b6f043820
--- /dev/null
+++ b/docs/rules/template-no-action.md
@@ -0,0 +1,54 @@
+# ember/template-no-action
+
+<!-- end auto-generated rule header -->
+
+Disallows the use of `{{action}}` helper.
+
+The `{{action}}` helper is deprecated in favor of the `{{on}}` modifier and `{{fn}}` helper, which provide better performance and clearer intent.
+
+## Examples
+
+Examples of **incorrect** code for this rule:
+
+```gjs
+<template>
+  <button {{on "click" (action "save")}}>Save</button>
+</template>
+```
+
+```gjs
+<template>
+  {{action "doSomething"}}
+</template>
+```
+
+Examples of **correct** code for this rule:
+
+```gjs
+<template>
+  <button {{on "click" this.save}}>Save</button>
+</template>
+```
+
+```gjs
+<template>
+  <button {{on "click" (fn this.save "arg")}}>Save with arg</button>
+</template>
+```
+
+```gjs
+<template>
+  {{this.action}}
+</template>
+```
+
+## Migration
+
+- Replace `(action "methodName")` with method references or `(fn this.methodName)`
+- Replace `<button onclick={{action ...}}>` with `<button {{on "click" ...}}>`
+
+## References
+
+- [eslint-plugin-ember template-no-action](https://github.com/ember-cli/eslint-plugin-ember/blob/master/docs/rules/template-no-action.md)
+- [Ember.js Deprecations - action helper](https://deprecations.emberjs.com/v3.x/#toc_action-helper)
+- [Ember Modifier Documentation](https://guides.emberjs.com/release/components/template-lifecycle-dom-and-modifiers/)
diff --git a/lib/rules/template-no-action.js b/lib/rules/template-no-action.js
new file mode 100644
index 0000000000..e11ec0eb71
--- /dev/null
+++ b/lib/rules/template-no-action.js
@@ -0,0 +1,70 @@
+function isActionHelper(node) {
+  if (!node.path || node.path.type !== 'GlimmerPathExpression') {
+    return false;
+  }
+
+  // Check if it's the action helper (not this.action or @action)
+  const path = node.path;
+  if (path.original === 'action') {
+    // Check head.type to avoid deprecated data/this properties
+    const head = path.head;
+    if (head && (head.type === 'AtHead' || head.type === 'ThisHead')) {
+      return false;
+    }
+    return true;
+  }
+
+  return false;
+}
+
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'disallow {{action}} helper',
+      category: 'Deprecations',
+      strictGjs: true,
+      strictGts: true,
+      url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/template-no-action.md',
+    },
+    fixable: null,
+    schema: [],
+    messages: {
+      subExpression:
+        'Do not use `action` as (action ...). Instead, use the `on` modifier and `fn` helper.',
+      mustache: 'Do not use `action` in templates. Instead, use the `on` modifier and `fn` helper.',
+    },
+  },
+
+  create(context) {
+    return {
+      GlimmerSubExpression(node) {
+        if (isActionHelper(node)) {
+          context.report({
+            node,
+            messageId: 'subExpression',
+          });
+        }
+      },
+
+      GlimmerMustacheStatement(node) {
+        // Skip if inside an attribute
+        let parent = node.parent;
+        while (parent) {
+          if (parent.type === 'GlimmerAttrNode') {
+            return;
+          }
+          parent = parent.parent;
+        }
+
+        if (isActionHelper(node)) {
+          context.report({
+            node,
+            messageId: 'mustache',
+          });
+        }
+      },
+    };
+  },
+};
diff --git a/tests/lib/rules/template-no-action.js b/tests/lib/rules/template-no-action.js
new file mode 100644
index 0000000000..614333ac98
--- /dev/null
+++ b/tests/lib/rules/template-no-action.js
@@ -0,0 +1,61 @@
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const rule = require('../../../lib/rules/template-no-action');
+const RuleTester = require('eslint').RuleTester;
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+const ruleTester = new RuleTester({
+  parser: require.resolve('ember-eslint-parser'),
+  parserOptions: { ecmaVersion: 2022, sourceType: 'module' },
+});
+
+ruleTester.run('template-no-action', rule, {
+  valid: [
+    `<template>
+      <button {{on "click" this.handleClick}}>Click</button>
+    </template>`,
+    `<template>
+      <button {{on "click" (fn this.save "arg")}}>Save</button>
+    </template>`,
+    `<template>
+      {{this.action}}
+    </template>`,
+    `<template>
+      {{@action}}
+    </template>`,
+  ],
+
+  invalid: [
+    {
+      code: `<template>
+        <button {{on "click" (action "save")}}>Save</button>
+      </template>`,
+      output: null,
+      errors: [
+        {
+          message:
+            'Do not use `action` as (action ...). Instead, use the `on` modifier and `fn` helper.',
+          type: 'GlimmerSubExpression',
+        },
+      ],
+    },
+    {
+      code: `<template>
+        {{action "doSomething"}}
+      </template>`,
+      output: null,
+      errors: [
+        {
+          message:
+            'Do not use `action` in templates. Instead, use the `on` modifier and `fn` helper.',
+          type: 'GlimmerMustacheStatement',
+        },
+      ],
+    },
+  ],
+});