From e7c69f2aaddb1cff9c4f77933c54d54f36e07ef2 Mon Sep 17 00:00:00 2001
From: Edward Faulkner <edward@eaf4.com>
Date: Fri, 28 Feb 2025 16:21:54 -0500
Subject: [PATCH 1/2] Printer bug: empty string literal args are dropped

---
 packages/@glimmer/syntax/test/generation/print-test.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/@glimmer/syntax/test/generation/print-test.ts b/packages/@glimmer/syntax/test/generation/print-test.ts
index 4a1a75d98..7bfa6a201 100644
--- a/packages/@glimmer/syntax/test/generation/print-test.ts
+++ b/packages/@glimmer/syntax/test/generation/print-test.ts
@@ -94,6 +94,9 @@ let templates = [
 
   // Comment in Angle Bracket component
   '<Foo {{!-- This is a comment --}} attribute></Foo>',
+
+  // Empty string literal args
+  `<Hello @world="" />`
 ];
 
 QUnit.module('[glimmer-syntax] Code generation', () => {

From 948a249eefb8cc5b4c311d38b4defeda2dc81645 Mon Sep 17 00:00:00 2001
From: Edward Faulkner <edward@eaf4.com>
Date: Mon, 3 Mar 2025 12:02:15 -0500
Subject: [PATCH 2/2] proposed fix

---
 packages/@glimmer/syntax/lib/generation/printer.ts     | 4 +++-
 packages/@glimmer/syntax/test/generation/print-test.ts | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/@glimmer/syntax/lib/generation/printer.ts b/packages/@glimmer/syntax/lib/generation/printer.ts
index 2be912e77..3765a55ef 100644
--- a/packages/@glimmer/syntax/lib/generation/printer.ts
+++ b/packages/@glimmer/syntax/lib/generation/printer.ts
@@ -285,7 +285,9 @@ export default class Printer {
     let { name, value } = attr;
 
     this.buffer += name;
-    if (value.type !== 'TextNode' || value.chars.length > 0) {
+    const isAttribute = !name.startsWith('@');
+    const shouldElideValue = isAttribute && value.type == 'TextNode' && value.chars.length === 0;
+    if (!shouldElideValue) {
       this.buffer += '=';
       this.AttrNodeValue(value);
     }
diff --git a/packages/@glimmer/syntax/test/generation/print-test.ts b/packages/@glimmer/syntax/test/generation/print-test.ts
index 7bfa6a201..c1214009c 100644
--- a/packages/@glimmer/syntax/test/generation/print-test.ts
+++ b/packages/@glimmer/syntax/test/generation/print-test.ts
@@ -95,8 +95,8 @@ let templates = [
   // Comment in Angle Bracket component
   '<Foo {{!-- This is a comment --}} attribute></Foo>',
 
-  // Empty string literal args
-  `<Hello @world="" />`
+  // Empty string literal: arguments use ="" while attributes are valueless
+  `<Hello @world="" data-foo />`,
 ];
 
 QUnit.module('[glimmer-syntax] Code generation', () => {