editor: Fix block comment with same prefix as line comment incorrectly extending on new line (#34156)

Closes #33930

Release Notes:

- Fixed `--[[` incorrectly extending `--` upon a new line in Lua.

crates/editor/src/editor.rs

@@ -4381,7 +4381,7 @@ impl Editor {
                                     .take_while(|c| c.is_whitespace())
                                     .count();
                                 let comment_candidate = snapshot
-                                    .chars_for_range(range)
+                                    .chars_for_range(range.clone())
                                     .skip(num_of_whitespaces)
                                     .take(max_len_of_delimiter)
                                     .collect::<String>();
@@ -4397,6 +4397,22 @@ impl Editor {
                                     })
                                     .max_by_key(|(_, len)| *len)?;
 
+                                if let Some((block_start, _)) = language.block_comment_delimiters()
+                                {
+                                    let block_start_trimmed = block_start.trim_end();
+                                    if block_start_trimmed.starts_with(delimiter.trim_end()) {
+                                        let line_content = snapshot
+                                            .chars_for_range(range)
+                                            .skip(num_of_whitespaces)
+                                            .take(block_start_trimmed.len())
+                                            .collect::<String>();
+
+                                        if line_content.starts_with(block_start_trimmed) {
+                                            return None;
+                                        }
+                                    }
+                                }
+
                                 let cursor_is_placed_after_comment_marker =
                                     num_of_whitespaces + trimmed_len <= start_point.column as usize;
                                 if cursor_is_placed_after_comment_marker {

crates/editor/src/editor_tests.rs

@@ -3080,6 +3080,45 @@ async fn test_newline_documentation_comments(cx: &mut TestAppContext) {
     "});
 }
 
+#[gpui::test]
+async fn test_newline_comments_with_block_comment(cx: &mut TestAppContext) {
+    init_test(cx, |settings| {
+        settings.defaults.tab_size = NonZeroU32::new(4)
+    });
+
+    let lua_language = Arc::new(Language::new(
+        LanguageConfig {
+            line_comments: vec!["--".into()],
+            block_comment: Some(("--[[".into(), "]]".into())),
+            ..LanguageConfig::default()
+        },
+        None,
+    ));
+
+    let mut cx = EditorTestContext::new(cx).await;
+    cx.update_buffer(|buffer, cx| buffer.set_language(Some(lua_language), cx));
+
+    // Line with line comment should extend
+    cx.set_state(indoc! {"
+        --ˇ
+    "});
+    cx.update_editor(|e, window, cx| e.newline(&Newline, window, cx));
+    cx.assert_editor_state(indoc! {"
+        --
+        --ˇ
+    "});
+
+    // Line with block comment that matches line comment should not extend
+    cx.set_state(indoc! {"
+        --[[ˇ
+    "});
+    cx.update_editor(|e, window, cx| e.newline(&Newline, window, cx));
+    cx.assert_editor_state(indoc! {"
+        --[[
+        ˇ
+    "});
+}
+
 #[gpui::test]
 fn test_insert_with_old_selections(cx: &mut TestAppContext) {
     init_test(cx, |_| {});