From 2cbbfe53816808c5732579a9997a9dc11bd8a614 Mon Sep 17 00:00:00 2001
From: Alex Kanunnikov <lifeart92@gmail.com>
Date: Mon, 30 Mar 2026 11:30:53 +0000
Subject: [PATCH 1/2] fix: externalize prettier/plugins/estree to prevent
 bundling stale code

The vite config listed `prettier/plugins/estree.js` as external, but the
source imports `prettier/plugins/estree` (no .js extension). This mismatch
caused vite to bundle prettier's estree printer into the plugin instead of
keeping it external. When the user installs a newer version of prettier
(e.g. 3.6.2), the plugin still uses the old bundled estree code whose
`canAttachComment` function expects 2 arguments, while prettier 3.6+'s
core calls it with 1 argument. This causes a crash:

  TypeError: undefined is not iterable (cannot read property Symbol(Symbol.iterator))

when formatting any .gts file that contains both a comment and a <template> tag.

The fix removes the .js extension from the external config so it matches
the actual import paths. Also adds a regression test case.

Closes #424
---
 tests/cases/gts/comment-with-template.gts     |  4 +++
 .../__snapshots__/format.test.ts.snap         |  8 ++++++
 tests/unit-tests/build-externals.test.ts      | 27 +++++++++++++++++++
 .../__snapshots__/semi-false.test.ts.snap     |  8 ++++++
 .../template-export-default.test.ts.snap      |  8 ++++++
 vite.config.mjs                               |  4 +--
 6 files changed, 57 insertions(+), 2 deletions(-)
 create mode 100644 tests/cases/gts/comment-with-template.gts
 create mode 100644 tests/unit-tests/build-externals.test.ts

diff --git a/tests/cases/gts/comment-with-template.gts b/tests/cases/gts/comment-with-template.gts
new file mode 100644
index 00000000..ba3ccab6
--- /dev/null
+++ b/tests/cases/gts/comment-with-template.gts
@@ -0,0 +1,4 @@
+// A comment before template
+<template>
+  <div>hello</div>
+</template>
diff --git a/tests/unit-tests/__snapshots__/format.test.ts.snap b/tests/unit-tests/__snapshots__/format.test.ts.snap
index 41951c2a..514229c9 100644
--- a/tests/unit-tests/__snapshots__/format.test.ts.snap
+++ b/tests/unit-tests/__snapshots__/format.test.ts.snap
@@ -295,6 +295,14 @@ const three = <template>{{if true "true"}}</template>;
 "
 `;
 
+exports[`format > config > default > it formats ../cases/gts/comment-with-template.gts 1`] = `
+"// A comment before template
+<template>
+  <div>hello</div>
+</template>
+"
+`;
+
 exports[`format > config > default > it formats ../cases/gts/complex.gts 1`] = `
 "import { on } from "@ember/modifier";
 import { service } from "@ember/service";
diff --git a/tests/unit-tests/build-externals.test.ts b/tests/unit-tests/build-externals.test.ts
new file mode 100644
index 00000000..30712a5b
--- /dev/null
+++ b/tests/unit-tests/build-externals.test.ts
@@ -0,0 +1,27 @@
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import { describe, expect, test } from 'vitest';
+
+describe('build externals', () => {
+  const distPath = resolve(
+    import.meta.dirname,
+    '../../dist/prettier-plugin-ember-template-tag.js',
+  );
+
+  test('prettier/plugins/estree is externalized, not bundled', () => {
+    const dist = readFileSync(distPath, 'utf-8');
+
+    // The dist should require estree as an external dependency
+    expect(dist).toContain('require("prettier/plugins/estree")');
+
+    // The dist should NOT contain estree printer internals (canAttachComment is
+    // a function from the estree printer that would be present if bundled)
+    expect(dist).not.toMatch(/function\s+\w*canAttachComment/);
+  });
+
+  test('prettier/plugins/babel is externalized, not bundled', () => {
+    const dist = readFileSync(distPath, 'utf-8');
+
+    expect(dist).toContain('require("prettier/plugins/babel")');
+  });
+});
diff --git a/tests/unit-tests/config/__snapshots__/semi-false.test.ts.snap b/tests/unit-tests/config/__snapshots__/semi-false.test.ts.snap
index 0fc42c7d..fb4527d1 100644
--- a/tests/unit-tests/config/__snapshots__/semi-false.test.ts.snap
+++ b/tests/unit-tests/config/__snapshots__/semi-false.test.ts.snap
@@ -295,6 +295,14 @@ const three = <template>{{if true "true"}}</template>
 "
 `;
 
+exports[`config > semi: false > it formats ../cases/gts/comment-with-template.gts 1`] = `
+"// A comment before template
+<template>
+  <div>hello</div>
+</template>
+"
+`;
+
 exports[`config > semi: false > it formats ../cases/gts/complex.gts 1`] = `
 "import { on } from "@ember/modifier"
 import { service } from "@ember/service"
diff --git a/tests/unit-tests/config/__snapshots__/template-export-default.test.ts.snap b/tests/unit-tests/config/__snapshots__/template-export-default.test.ts.snap
index c10016e6..e64fd9b4 100644
--- a/tests/unit-tests/config/__snapshots__/template-export-default.test.ts.snap
+++ b/tests/unit-tests/config/__snapshots__/template-export-default.test.ts.snap
@@ -295,6 +295,14 @@ const three = <template>{{if true "true"}}</template>;
 "
 `;
 
+exports[`config > templateExportDefault: true > it formats ../cases/gts/comment-with-template.gts 1`] = `
+"// A comment before template
+<template>
+  <div>hello</div>
+</template>
+"
+`;
+
 exports[`config > templateExportDefault: true > it formats ../cases/gts/complex.gts 1`] = `
 "import { on } from "@ember/modifier";
 import { service } from "@ember/service";
diff --git a/vite.config.mjs b/vite.config.mjs
index 416cc616..9694b6b6 100644
--- a/vite.config.mjs
+++ b/vite.config.mjs
@@ -6,8 +6,8 @@ export default defineConfig({
       external: [
         'content-tag',
         'prettier',
-        'prettier/plugins/estree.js',
-        'prettier/plugins/babel.js',
+        'prettier/plugins/estree',
+        'prettier/plugins/babel',
       ],
     },
     lib: {

From c66c56f6788677707a1c6369222bde082f7faa37 Mon Sep 17 00:00:00 2001
From: Alex Kanunnikov <lifeart92@gmail.com>
Date: Tue, 31 Mar 2026 01:24:45 +0000
Subject: [PATCH 2/2] fix: resolve CI lint errors and add build step for
 prettier version tests

Fix lint issues in build-externals test (import style, naming conventions,
encoding identifier) and add missing `pnpm build` step to test-prettier-versions
CI job so the dist file exists when the build-externals test runs. Also make
assertions resilient to both CJS and ESM output formats.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 .github/workflows/ci.yml                 |  2 ++
 tests/unit-tests/build-externals.test.ts | 21 +++++++++++++--------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 807e3cc9..fd22fda3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -77,4 +77,6 @@ jobs:
 
       - run: pnpm install --frozen-lockfile
 
+      - run: pnpm build
+
       - run: pnpm test
diff --git a/tests/unit-tests/build-externals.test.ts b/tests/unit-tests/build-externals.test.ts
index 30712a5b..d763baf9 100644
--- a/tests/unit-tests/build-externals.test.ts
+++ b/tests/unit-tests/build-externals.test.ts
@@ -1,27 +1,32 @@
 import { readFileSync } from 'node:fs';
-import { resolve } from 'node:path';
+import path from 'node:path';
+
 import { describe, expect, test } from 'vitest';
 
 describe('build externals', () => {
-  const distPath = resolve(
+  const distributionPath = path.resolve(
     import.meta.dirname,
     '../../dist/prettier-plugin-ember-template-tag.js',
   );
 
   test('prettier/plugins/estree is externalized, not bundled', () => {
-    const dist = readFileSync(distPath, 'utf-8');
+    const distribution = readFileSync(distributionPath, 'utf8');
 
-    // The dist should require estree as an external dependency
-    expect(dist).toContain('require("prettier/plugins/estree")');
+    // The dist should reference estree as an external dependency (require or import)
+    expect(distribution).toMatch(
+      /require\(["']prettier\/plugins\/estree["']\)|from\s+["']prettier\/plugins\/estree["']/,
+    );
 
     // The dist should NOT contain estree printer internals (canAttachComment is
     // a function from the estree printer that would be present if bundled)
-    expect(dist).not.toMatch(/function\s+\w*canAttachComment/);
+    expect(distribution).not.toMatch(/function\s+\w*canAttachComment/);
   });
 
   test('prettier/plugins/babel is externalized, not bundled', () => {
-    const dist = readFileSync(distPath, 'utf-8');
+    const distribution = readFileSync(distributionPath, 'utf8');
 
-    expect(dist).toContain('require("prettier/plugins/babel")');
+    expect(distribution).toMatch(
+      /require\(["']prettier\/plugins\/babel["']\)|from\s+["']prettier\/plugins\/babel["']/,
+    );
   });
 });