[Glimmer] Preserve tilde comments (#9082)

Co-authored-by: fisker <lionkay@gmail.com>

changelog_unreleased/handlebars/9082.md

@@ -0,0 +1,19 @@
+#### Preserve tilde comments (#9082 by @kangax, @fisker)
+
+<!-- prettier-ignore -->
+```hbs
+{{!-- Input --}}
+{{~! Comment }}
+{{! Comment ~}}
+{{~! Comment ~}}
+
+{{!-- Prettier stable --}}
+{{! Comment }}
+{{! Comment }}
+{{! Comment }}
+
+{{!-- Prettier master --}}
+{{~! Comment }}
+{{! Comment ~}}
+{{~! Comment ~}}
+```

src/language-handlebars/printer-glimmer.js

@@ -268,8 +268,26 @@ function print(path, options, print) {
       ]);
     }
     case "MustacheCommentStatement": {
+      const start = locStart(n);
+      const end = locEnd(n);
+      // Starts with `{{~`
+      const isLeftWhiteSpaceSensitive =
+        options.originalText.charAt(start + 2) === "~";
+      // Ends with `{{~`
+      const isRightWhitespaceSensitive =
+        options.originalText.charAt(end - 3) === "~";
+
       const dashes = n.value.includes("}}") ? "--" : "";
-      return concat(["{{!", dashes, n.value, dashes, "}}"]);
+      return concat([
+        "{{",
+        isLeftWhiteSpaceSensitive ? "~" : "",
+        "!",
+        dashes,
+        n.value,
+        dashes,
+        isRightWhitespaceSensitive ? "~" : "",
+        "}}",
+      ]);
     }
     case "PathExpression": {
       return n.original;

tests/handlebars/comment/__snapshots__/jsfmt.spec.js.snap

@@ -21,9 +21,22 @@ printWidth: 80
 <div class="entry">
   {{! This comment will not be in the output }}
   {{!-- This comment as }} and will not be in the output --}}
+  {{~! This comment will not be in the output }}
+  {{! This comment will not be in the output ~}}
+  {{~! This comment will not be in the output ~}}
+  {{~!
+comment
+ ~}}
+  {{~! 1 ~}}{{~! 2 ~}}
   <!-- This comment will be in the output -->
 </div>
 
+<div>
+  {{~!~}}
+  <span></span>
+  {{~!~}}
+</div>
+
 =====================================output=====================================
 <div>
   {{! Foo }}
@@ -40,7 +53,20 @@ printWidth: 80
 <div class="entry">
   {{! This comment will not be in the output }}
   {{!-- This comment as }} and will not be in the output --}}
+  {{~! This comment will not be in the output }}
+  {{! This comment will not be in the output ~}}
+  {{~! This comment will not be in the output ~}}
+  {{~!
+comment
+ ~}}
+  {{~! 1 ~}}{{~! 2 ~}}
   <!-- This comment will be in the output -->
 </div>
+
+<div>
+  {{~!~}}
+  <span></span>
+  {{~!~}}
+</div>
 ================================================================================
 `;

tests/handlebars/comment/comments.hbs

@@ -13,5 +13,18 @@
 <div class="entry">
   {{! This comment will not be in the output }}
   {{!-- This comment as }} and will not be in the output --}}
+  {{~! This comment will not be in the output }}
+  {{! This comment will not be in the output ~}}
+  {{~! This comment will not be in the output ~}}
+  {{~!
+comment
+ ~}}
+  {{~! 1 ~}}{{~! 2 ~}}
   <!-- This comment will be in the output -->
 </div>
+
+<div>
+  {{~!~}}
+  <span></span>
+  {{~!~}}
+</div>

tests/misc/errors/handlebars/__snapshots__/jsfmt.spec.js.snap

@@ -37,3 +37,23 @@ Expecting 'ID', 'STRING', 'NUMBER', 'BOOLEAN', 'UNDEFINED', 'NULL', 'DATA', got
     |   ^
   4 | "
 `;
+
+exports[`tilde-comments-1.hbs [glimmer] format 1`] = `
+"Parse error on line 1:
+{{~}}
+---^
+Expecting 'ID', 'STRING', 'NUMBER', 'BOOLEAN', 'UNDEFINED', 'NULL', 'DATA', got 'CLOSE' (1:4)
+> 1 | {{~}}
+    |    ^
+  2 | "
+`;
+
+exports[`tilde-comments-2.hbs [glimmer] format 1`] = `
+"Parse error on line 1:
+{{~~}}
+---^
+Expecting 'ID', 'STRING', 'NUMBER', 'BOOLEAN', 'UNDEFINED', 'NULL', 'DATA', got 'CLOSE' (1:4)
+> 1 | {{~~}}
+    |    ^
+  2 | "
+`;

tests/misc/errors/handlebars/tilde-comments-1.hbs

@@ -0,0 +1 @@
+{{~}}

tests/misc/errors/handlebars/tilde-comments-2.hbs

@@ -0,0 +1 @@
+{{~~}}