fix(linter): don't remove empty blocks containing comments

.changeset/fix-lone-block-comments.md

@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#8685](https://github.com/biomejs/biome/issues/8685) where `noUselessLoneBlockStatements` would remove empty blocks containing comments. The rule now preserves these blocks since comments may contain important information like TODOs or commented-out code.

crates/biome_js_analyze/src/lint/complexity/no_useless_lone_block_statements.rs

@@ -77,6 +77,10 @@ impl Rule for NoUselessLoneBlockStatements {
         }
 
         if block.statements().is_empty() {
+            // Preserve empty blocks that contain comments
+            if block.syntax().has_comments_descendants() {
+                return None;
+            }
             return Some(());
         }
 

crates/biome_js_analyze/tests/specs/complexity/noUselessLoneBlockStatements/valid.cjs

@@ -84,3 +84,21 @@ switch (foo) {
     break;
   }
 }
+
+// Empty blocks with comments should not trigger diagnostics
+{
+    // TODO: add error handling
+}
+
+{
+    /*
+     * Multi-line block comment
+     * should also be preserved
+     */
+}
+
+function withCommentedCode() {
+    {
+        // return x + y;
+    }
+}

crates/biome_js_analyze/tests/specs/complexity/noUselessLoneBlockStatements/valid.cjs.snap

@@ -91,4 +91,22 @@ switch (foo) {
   }
 }
 
+// Empty blocks with comments should not trigger diagnostics
+{
+    // TODO: add error handling
+}
+
+{
+    /*
+     * Multi-line block comment
+     * should also be preserved
+     */
+}
+
+function withCommentedCode() {
+    {
+        // return x + y;
+    }
+}
+
 ```