DictProperty and ListProperty creation fails within kv, when values are other than strings or integers

[dessant]

I have tested with values like True, False, None and a kivy widget class, other property types may be affected too.

from kivy.app import App
from kivy.lang import Builder
from kivy.factory import Factory
from kivy.uix.button import Button

kv = """
#: import BoxLayout kivy.uix.boxlayout.BoxLayout

<NewB@Widget>:
    l1: [1, 'hgfh']

    l2: [BoxLayout]
    l3: [True, False]
    d: {'id': None}

<Test>:
    text: 'Print property types'
    on_press: root.callback()
"""

Builder.load_string(kv)

class Test(Button):

    def callback(self):
        new = Factory.NewB()
        print(type(new.l1))
        print(type(new.l2))
        print(type(new.l3))
        print(type(new.d))

class TestApp(App):
    def build(self):
        return Test()

if __name__ == '__main__':
    TestApp().run()

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[matham]

The code below is a staring point to fix the issue. I did not check though if it'd work with templates. Also, if the list/dict is using a kv available keyword (e.g. root) it might still not work because at the point that we create the missing props, we have not initialized the idmap with those keywords.

diff --git a/kivy/lang.py b/kivy/lang.py
index 458cef4..d3c9c1f 100755
--- a/kivy/lang.py
+++ b/kivy/lang.py
@@ -224,7 +224,7 @@ Examples of valid statements are:
 An example of a invalid statement:

 .. code-block:: python
-
+
     on_state:
         if self.state == 'normal':
             print('normal')
@@ -1032,7 +1032,12 @@ class ParserRule(object):
                 continue
             value = self.properties[name].co_value
             if type(value) is CodeType:
-                value = None
+                idmap = copy(global_idmap)
+                idmap['self'] = widget.proxy_ref
+                try:
+                    value = eval(value, idmap)
+                except:
+                    value = None
             widget.create_property(name, value)

     def _forbid_selectors(self):

[stale[bot]]

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