[CodeEdit] Fix folding for comments mixed with code region tags.

Co-authored-by: Kit Bishop <[email protected]>

Author: Aziroshin

scene/gui/code_edit.cpp

@@ -1645,12 +1645,12 @@ bool CodeEdit::can_fold_line(int p_line) const {
 		if (delimiter_end_line == p_line) {
 			/* Check we are the start of the block. */
 			if (p_line - 1 >= 0) {
-				if ((in_string != -1 && is_in_string(p_line - 1) != -1) || (in_comment != -1 && is_in_comment(p_line - 1) != -1)) {
+				if ((in_string != -1 && is_in_string(p_line - 1) != -1) || (in_comment != -1 && is_in_comment(p_line - 1) != -1 && !is_line_code_region_start(p_line - 1) && !is_line_code_region_end(p_line - 1))) {
 					return false;
 				}
 			}
 			/* Check it continues for at least one line. */
-			return ((in_string != -1 && is_in_string(p_line + 1) != -1) || (in_comment != -1 && is_in_comment(p_line + 1) != -1));
+			return ((in_string != -1 && is_in_string(p_line + 1) != -1) || (in_comment != -1 && is_in_comment(p_line + 1) != -1 && !is_line_code_region_start(p_line + 1) && !is_line_code_region_end(p_line + 1)));
 		}
 		return ((in_string != -1 && is_in_string(delimiter_end_line) != -1) || (in_comment != -1 && is_in_comment(delimiter_end_line) != -1));
 	}
@@ -1705,6 +1705,10 @@ void CodeEdit::fold_line(int p_line) {
 					if ((in_string != -1 && is_in_string(i) == -1) || (in_comment != -1 && is_in_comment(i) == -1)) {
 						break;
 					}
+					if (in_comment != -1 && (is_line_code_region_start(i) || is_line_code_region_end(i))) {
+						// A code region tag should split a comment block, ending it early.
+						break;
+					}
 					end_line = i;
 				}
 			}

tests/scene/test_code_edit.h

@@ -3269,6 +3269,47 @@ TEST_CASE("[SceneTree][CodeEdit] folding") {
 		CHECK(code_edit->get_next_visible_line_offset_from(1, 1) == 4);
 	}
 
+	SUBCASE("[CodeEdit] folding comments including and/or adjacent to code regions") {
+		code_edit->add_comment_delimiter("#", "", true);
+
+		// Single line comment directly above a code region tag is not foldable.
+		code_edit->set_text("#line0\n#region a\nnothing\n#line3\n#endregion");
+		CHECK_FALSE(code_edit->can_fold_line(0));
+		CHECK_FALSE(code_edit->can_fold_line(3));
+
+		// Comment blocks.
+		// Foldable even when directly below a code region start tag.
+		code_edit->set_text("#line0\n#line1\n#region a\n#line3\n#line4\nnothing\n#endregion");
+		CHECK(code_edit->can_fold_line(3));
+
+		// Doesn't fold beyond region start tag.
+		code_edit->fold_line(0);
+		CHECK(code_edit->is_line_folded(0));
+		CHECK_EQ(code_edit->get_visible_line_count_in_range(0, 1), 1);
+		CHECK_EQ(code_edit->get_visible_line_count_in_range(2, 2), 1);
+
+		// Foldable even when directly below a code region end tag.
+		code_edit->set_text("#region a\nnothing\n#line2\n#line3\n#endregion\n#line5\n#line6");
+		CHECK(code_edit->can_fold_line(5));
+
+		// Doesn't fold beyond region end tag.
+		code_edit->fold_line(2);
+		CHECK(code_edit->is_line_folded(2));
+		CHECK_EQ(code_edit->get_visible_line_count_in_range(2, 3), 1);
+		CHECK_EQ(code_edit->get_visible_line_count_in_range(4, 4), 1);
+
+		code_edit->add_comment_delimiter("/*", "*/", false);
+
+		// Multiline comments.
+		// Folds a region tag inside it.
+		code_edit->set_text("/*\nnothing\n#region a\n*/\n#endregion");
+		CHECK(code_edit->can_fold_line(0));
+		code_edit->fold_line(0);
+		CHECK(code_edit->is_line_folded(0));
+		CHECK_EQ(code_edit->get_visible_line_count_in_range(0, 3), 1);
+		CHECK_EQ(code_edit->get_visible_line_count_in_range(4, 4), 1);
+	}
+
 	SUBCASE("[CodeEdit] folding carets") {
 		// Folding a line moves all carets that would be hidden.
 		code_edit->set_text("test\n\tline1\n\t\tline 2\n");