Editor crash when editing signal connections

[KoBeWi]

Tested versions

4.5 46c495c

System information

W10

Issue description

ERROR: Parameter "mem" is null.
   at: Memory::alloc_static (C:\godot_source\core/os/memory.cpp:111)
ERROR: Out of memory
   at: (C:\godot_source\core/templates/local_vector.h:179)

LocalVector<Pair<enum Variant::Type,StringName>,unsigned int,0,0>::reserve(unsigned int p_size) Line 179 (c:\godot_source\core\templates\local_vector.h:179)
ConnectDialog::_filter_method_list(const List<MethodInfo,DefaultAllocator> & p_methods, const MethodInfo & p_signal, const String & p_search_string) Line 294 (c:\godot_source\editor\connections_dialog.cpp:294)
ConnectDialog::_update_method_tree() Line 385 (c:\godot_source\editor\connections_dialog.cpp:385)
ConnectDialog::_tree_node_selected() Line 180 (c:\godot_source\editor\connections_dialog.cpp:180)
call_with_variant_args_helper<ConnectDialog>(ConnectDialog * p_instance, void(ConnectDialog::*)() p_method, const Variant * * p_args, Callable::CallError & r_error, IndexSequence<> __formal) Line 228 (c:\godot_source\core\variant\binder_common.h:228)
call_with_variant_args<ConnectDialog>(ConnectDialog * p_instance, void(ConnectDialog::*)() p_method, const Variant * * p_args, int p_argcount, Callable::CallError & r_error) Line 338 (c:\godot_source\core\variant\binder_common.h:338)
CallableCustomMethodPointer<ConnectDialog,void>::call(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 107 (c:\godot_source\core\object\callable_method_pointer.h:107)
Callable::callp(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 58 (c:\godot_source\core\variant\callable.cpp:58)
Object::emit_signalp(const StringName & p_name, const Variant * * p_args, int p_argcount) Line 1288 (c:\godot_source\core\object\object.cpp:1288)
Node::emit_signalp(const StringName & p_name, const Variant * * p_args, int p_argcount) Line 4130 (c:\godot_source\scene\main\node.cpp:4130)
Object::emit_signal<>(const StringName & p_name) Line 941 (c:\godot_source\core\object\object.h:941)
SceneTreeEditor::set_selected(Node * p_node, bool p_emit_selected) Line 1471 (c:\godot_source\editor\gui\scene_tree_editor.cpp:1471)
ConnectDialog::set_dst_node(Node * p_node) Line 532 (c:\godot_source\editor\connections_dialog.cpp:532)
ConnectDialog::init(const ConnectDialog::ConnectionData & p_cd, const Vector<String> & p_signal_args, bool p_edit) Line 675 (c:\godot_source\editor\connections_dialog.cpp:675)
ConnectionsDock::_open_connection_dialog(TreeItem & p_item) Line 1207 (c:\godot_source\editor\connections_dialog.cpp:1207)
ConnectionsDock::_tree_item_activated() Line 1166 (c:\godot_source\editor\connections_dialog.cpp:1166)
call_with_variant_args_helper<ConnectionsDock>(ConnectionsDock * p_instance, void(ConnectionsDock::*)() p_method, const Variant * * p_args, Callable::CallError & r_error, IndexSequence<> __formal) Line 228 (c:\godot_source\core\variant\binder_common.h:228)
call_with_variant_args<ConnectionsDock>(ConnectionsDock * p_instance, void(ConnectionsDock::*)() p_method, const Variant * * p_args, int p_argcount, Callable::CallError & r_error) Line 338 (c:\godot_source\core\variant\binder_common.h:338)
CallableCustomMethodPointer<ConnectionsDock,void>::call(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 107 (c:\godot_source\core\object\callable_method_pointer.h:107)
Callable::callp(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 58 (c:\godot_source\core\variant\callable.cpp:58)

Steps to reproduce

1. Open the attached scene
2. Click ItemList
3. In Node dock, edit the item_selected connection and press OK (without any changes)
4. Click Tree
5. In Node dock, double click cell_selected signal

Minimal reproduction project (MRP)

Crasher.tscn.txt

[Ivorforce]

The code in question:

godot/editor/connections_dialog.cpp

Lines 287 to 293 in 46c495c

	List<MethodInfo> ConnectDialog::_filter_method_list(const List<MethodInfo> &p_methods, const MethodInfo &p_signal, const String &p_search_string) const {
	bool check_signal = compatible_methods_only->is_pressed();
	List<MethodInfo> ret;
	LocalVector<Pair<Variant::Type, StringName>> effective_args;
	int unbind = get_unbinds();
	effective_args.reserve(p_signal.arguments.size() - unbind);

Looks like it's reserving for a - b. An obvious potential cause is overflow, leading to reserve(INT32_MAX), causing the out of memory failures. This would mean p_signal.arguments.size() < get_unbinds().

Probably caused by #91660, cc @AThousandShips

[AThousandShips]

Will take a look

[AThousandShips]

Indeed, this is the cause, making a fix, coming full circle! Code bug report for bug caused by suggestion by the same person!