From 0f31453cfff47499e440117d658e6d10e1ec5680 Mon Sep 17 00:00:00 2001
From: Lucas Duailibe <lucasds@gmail.com>
Date: Wed, 1 Dec 2021 12:47:27 -0300
Subject: [PATCH] [handlebars] Named blocks can't be self closing

---
 changelog_unreleased/handlebars/11899.md      | 23 ++++++++++++++++++
 src/language-handlebars/utils.js              |  1 +
 .../basics/__snapshots__/jsfmt.spec.js.snap   | 24 +++++++++++++++++++
 .../format/handlebars/basics/named-block.hbs  |  6 +++++
 4 files changed, 54 insertions(+)
 create mode 100644 changelog_unreleased/handlebars/11899.md
 create mode 100644 tests/format/handlebars/basics/named-block.hbs

diff --git a/changelog_unreleased/handlebars/11899.md b/changelog_unreleased/handlebars/11899.md
new file mode 100644
index 000000000000..13b5dc9cc3c4
--- /dev/null
+++ b/changelog_unreleased/handlebars/11899.md
@@ -0,0 +1,23 @@
+#### Support Glimmer's named blocks (#11899 by @duailibe)
+
+Prettier already supported this feature, but it converted empty named blocks to self-closing, which is not supported by the Glimmer compiler.
+
+See: [Glimmer's named blocks](https://emberjs.github.io/rfcs/0460-yieldable-named-blocks.html).
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+<Component>
+  <:named></:named>
+</Component>
+
+// Prettier stable
+<Component>
+  <:named />
+</Component>
+
+// Prettier main
+<Component>
+  <:named></:named>
+</Component>
+```
diff --git a/src/language-handlebars/utils.js b/src/language-handlebars/utils.js
index d4831d6f1c70..22ae28ce8224 100644
--- a/src/language-handlebars/utils.js
+++ b/src/language-handlebars/utils.js
@@ -25,6 +25,7 @@ function isLastNodeOfSiblings(path) {
 }
 
 function isUppercase(string) {
+  return /^[A-Z]+$/.test(string);
   return string.toUpperCase() === string;
 }
 
diff --git a/tests/format/handlebars/basics/__snapshots__/jsfmt.spec.js.snap b/tests/format/handlebars/basics/__snapshots__/jsfmt.spec.js.snap
index 5cad2bbce4e0..987bfa99cf08 100644
--- a/tests/format/handlebars/basics/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/format/handlebars/basics/__snapshots__/jsfmt.spec.js.snap
@@ -93,6 +93,30 @@ printWidth: 80
 ================================================================================
 `;
 
+exports[`named-block.hbs format 1`] = `
+====================================options=====================================
+parsers: ["glimmer"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+<ComponentWithNamedBlocks>
+  <:first-named-block></:first-named-block>
+  <:second-named-block> </:second-named-block>
+  <:named-block-with-comment>{{! Do not convert to an empty element}}</:named-block-with-comment>
+  <:named-block-with-content>Hello</:named-block-with-content>
+</ComponentWithNamedBlocks>
+
+=====================================output=====================================
+<ComponentWithNamedBlocks>
+  <:first-named-block></:first-named-block>
+  <:second-named-block> </:second-named-block>
+  <:named-block-with-comment
+  >{{! Do not convert to an empty element}}</:named-block-with-comment>
+  <:named-block-with-content>Hello</:named-block-with-content>
+</ComponentWithNamedBlocks>
+================================================================================
+`;
+
 exports[`nested-path.hbs format 1`] = `
 ====================================options=====================================
 parsers: ["glimmer"]
diff --git a/tests/format/handlebars/basics/named-block.hbs b/tests/format/handlebars/basics/named-block.hbs
new file mode 100644
index 000000000000..442a5a5875e5
--- /dev/null
+++ b/tests/format/handlebars/basics/named-block.hbs
@@ -0,0 +1,6 @@
+<ComponentWithNamedBlocks>
+  <:first-named-block></:first-named-block>
+  <:second-named-block> </:second-named-block>
+  <:named-block-with-comment>{{! Do not convert to an empty element}}</:named-block-with-comment>
+  <:named-block-with-content>Hello</:named-block-with-content>
+</ComponentWithNamedBlocks>