Merge pull request #94730 from dalexeev/gds-fix-while-locals-clearing

GDScript: Fix locals clearing after exiting `while` block

Author: akien-mga

modules/gdscript/gdscript_compiler.cpp

@@ -1901,7 +1901,7 @@ Error GDScriptCompiler::_parse_block(CodeGen &codegen, const GDScriptParser::Sui
 			case GDScriptParser::Node::MATCH: {
 				const GDScriptParser::MatchNode *match = static_cast<const GDScriptParser::MatchNode *>(s);
 
-				codegen.start_block(); // Add an extra block, since the binding pattern and @special variables belong to the branch scope.
+				codegen.start_block(); // Add an extra block, since @special locals belong to the match scope.
 
 				// Evaluate the match expression.
 				GDScriptCodeGenerator::Address value = codegen.add_local("@match_value", _gdtype_from_datatype(match->test->get_datatype(), codegen.script));
@@ -1939,7 +1939,7 @@ Error GDScriptCompiler::_parse_block(CodeGen &codegen, const GDScriptParser::Sui
 
 					const GDScriptParser::MatchBranchNode *branch = match->branches[j];
 
-					codegen.start_block(); // Create an extra block around for binds.
+					codegen.start_block(); // Add an extra block, since binds belong to the match branch scope.
 
 					// Add locals in block before patterns, so temporaries don't use the stack address for binds.
 					List<GDScriptCodeGenerator::Address> branch_locals = _add_block_locals(codegen, branch->block);
@@ -1991,13 +1991,15 @@ Error GDScriptCompiler::_parse_block(CodeGen &codegen, const GDScriptParser::Sui
 
 					_clear_block_locals(codegen, branch_locals);
 
-					codegen.end_block(); // Get out of extra block.
+					codegen.end_block(); // Get out of extra block for binds.
 				}
 
 				// End all nested `if`s.
 				for (int j = 0; j < match->branches.size(); j++) {
 					gen->write_endif();
 				}
+
+				codegen.end_block(); // Get out of extra block for match's @special locals.
 			} break;
 			case GDScriptParser::Node::IF: {
 				const GDScriptParser::IfNode *if_n = static_cast<const GDScriptParser::IfNode *>(s);
@@ -2031,7 +2033,9 @@ Error GDScriptCompiler::_parse_block(CodeGen &codegen, const GDScriptParser::Sui
 			case GDScriptParser::Node::FOR: {
 				const GDScriptParser::ForNode *for_n = static_cast<const GDScriptParser::ForNode *>(s);
 
-				codegen.start_block(); // Add an extra block, since the iterator and @special variables belong to the loop scope.
+				// Add an extra block, since the iterator and @special locals belong to the loop scope.
+				// Also we use custom logic to clear block locals.
+				codegen.start_block();
 
 				GDScriptCodeGenerator::Address iterator = codegen.add_local(for_n->variable->name, _gdtype_from_datatype(for_n->variable->get_datatype(), codegen.script));
 
@@ -2064,11 +2068,13 @@ Error GDScriptCompiler::_parse_block(CodeGen &codegen, const GDScriptParser::Sui
 
 				_clear_block_locals(codegen, loop_locals); // Outside loop, after block - for `break` and normal exit.
 
-				codegen.end_block(); // Get out of extra block.
+				codegen.end_block(); // Get out of extra block for loop iterator, @special locals, and custom locals clearing.
 			} break;
 			case GDScriptParser::Node::WHILE: {
 				const GDScriptParser::WhileNode *while_n = static_cast<const GDScriptParser::WhileNode *>(s);
 
+				codegen.start_block(); // Add an extra block, since we use custom logic to clear block locals.
+
 				gen->start_while_condition();
 
 				GDScriptCodeGenerator::Address condition = _parse_expression(codegen, err, while_n->condition);
@@ -2095,6 +2101,8 @@ Error GDScriptCompiler::_parse_block(CodeGen &codegen, const GDScriptParser::Sui
 				gen->write_endwhile();
 
 				_clear_block_locals(codegen, loop_locals); // Outside loop, after block - for `break` and normal exit.
+
+				codegen.end_block(); // Get out of extra block for custom locals clearing.
 			} break;
 			case GDScriptParser::Node::BREAK: {
 				gen->write_break();

modules/gdscript/tests/scripts/runtime/features/reset_local_var_on_exit_block.gd

@@ -1,10 +1,26 @@
 # GH-77666
-
-func test():
+func test_exit_if():
 	var ref := RefCounted.new()
 	print(ref.get_reference_count())
 
 	if true:
 		var _temp := ref
 
 	print(ref.get_reference_count())
+
+# GH-94654
+func test_exit_while():
+	var slots_data := []
+
+	while true:
+		@warning_ignore("confusable_local_declaration")
+		var slot = 42
+		slots_data.append(slot)
+		break
+
+	var slot: int = slots_data[0]
+	print(slot)
+
+func test():
+	test_exit_if()
+	test_exit_while()

modules/gdscript/tests/scripts/runtime/features/reset_local_var_on_exit_block.out

@@ -1,3 +1,4 @@
 GDTEST_OK
 1
 1
+42