Leak caused by returning objects from classes

[qarmin]

Pixelorama latest 0.61

When I open and close editor I have this errors

ERROR: ~List: Condition "_first != __null" is true.
   At: ./core/self_list.h:112.
ERROR: ~List: Condition "_first != __null" is true.
   At: ./core/self_list.h:112.
WARNING: cleanup: ObjectDB Instances still exist!
   At: core/object.cpp:2071.
ERROR: clear: Resources Still in use at Exit!
   At: core/resource.cpp:476.

This is Godot issue - https://github.com/godotengine/godot/issues/30668 - but I think that create here an issue may accelerate the resolution of the problem.

The problem is with two files

Leaked instance: GDScript:5494 - Resource name:  Path: res://Scripts/Palette/Palette.gd
Leaked instance: GDScript:5495 - Resource name:  Path: res://Scripts/Palette/PaletteColor.gd

Each file is named class(with class_name) which in one of its function returns an object of its own type PaletteColor.gd

extends Reference
class_name PaletteColor

func fromDict(input_dict : Dictionary) -> PaletteColor:
    var result = get_script().new()

    result.data = input_dict.data
    result.name = input_dict.name

    return result

and Palette.gd

class_name Palette

func deserialize(input_string : String) -> Palette:
    var result = get_script().new()

    var result_json = JSON.parse(input_string)

[OverloadedOrama]

Hello, thanks for reporting the issue. I wasn't aware that this would cause leaks. Should we try and find a workaround for this issue or should we just wait until it's fixed in Godot?

[qarmin]

Workaround for now is to remove all info about types, if type of returned object or created variable is same as type of class e.g.

class rr
var qq : rr = null      # will cause leak
var qq2                 # no leak
func zz() ->  rr:       # leak
pass
func zz2():             # no leak
pass

For now this patch should remove leak

diff --git a/Scripts/Palette/Palette.gd b/Scripts/Palette/Palette.gd
index f8ece9a..60ca46d 100644
--- a/Scripts/Palette/Palette.gd
+++ b/Scripts/Palette/Palette.gd
@@ -72,8 +72,8 @@ func save_to_file(path : String) -> void:
        file.store_string(_serialize())
        file.close()

-func duplicate() -> Palette:
-       var copy : Palette = get_script().new()
+func duplicate():
+       var copy = get_script().new()
        copy.name = name
        copy.comments = comments
        copy.editable = editable
@@ -96,7 +96,7 @@ func _serialize() -> String:

        return result

-func deserialize(input_string : String) -> Palette:
+func deserialize(input_string : String):
        var result = get_script().new()

        var result_json = JSON.parse(input_string)
@@ -120,8 +120,8 @@ func deserialize(input_string : String) -> Palette:

        return result

-func load_from_file(path : String) -> Palette:
-       var result : Palette = null
+func load_from_file(path : String):
+       var result = null
        var file = File.new()

        if file.file_exists(path):
diff --git a/Scripts/Palette/PaletteColor.gd b/Scripts/Palette/PaletteColor.gd
index 806f7fd..ef74967 100644
--- a/Scripts/Palette/PaletteColor.gd
+++ b/Scripts/Palette/PaletteColor.gd
@@ -29,7 +29,7 @@ func toDict() -> Dictionary:
                }
        return result

-func fromDict(input_dict : Dictionary) -> PaletteColor:
+func fromDict(input_dict : Dictionary):
        var result = get_script().new()

        result.data = input_dict.data
@@ -37,8 +37,8 @@ func fromDict(input_dict : Dictionary) -> PaletteColor:

        return result

-func duplicate() -> PaletteColor:
-       var copy : PaletteColor = get_script().new()
+func duplicate():
+       var copy = get_script().new()
        copy.data = data
        copy.name = name
-       return copy
\ No newline at end of file
+       return copy