widgetsscheme: Recognize and evaluate lazy signals

orangewidget/utils/signals.py

@@ -16,6 +16,8 @@
     InputSignal, OutputSignal, Single, Multiple, Default, NonDefault,
     Explicit, Dynamic
 )
+# imported here for easier use by widgets, pylint: disable=unused-import
+from orangecanvas.scheme.signalmanager import LazyValue
 
 from orangewidget.utils.messagewidget import MessagesWidget
 from orangewidget.workflow.utils import WeakKeyDefaultDict

orangewidget/workflow/widgetsscheme.py

@@ -40,7 +40,7 @@
 from orangecanvas.registry import WidgetDescription, OutputSignal
 
 from orangecanvas.scheme.signalmanager import (
-    SignalManager, Signal, compress_signals
+    SignalManager, Signal, compress_signals, LazyValue
 )
 from orangecanvas.scheme import Scheme, SchemeNode
 from orangecanvas.scheme.node import UserMessage
@@ -850,6 +850,8 @@ def process_signal_input_default(
     link = signal.link
     index = signal.index
     value = signal.value
+    if LazyValue.is_lazy(value):
+        value = value.get_value()
 
     index_existing = index_of(inputs, signal, eq=same_input_slot)
     if index < 0 and index_existing is not None:

setup.py

@@ -57,7 +57,7 @@
     "pyqtgraph",
     "AnyQt>=0.1.0",
     "typing_extensions>=3.7.4.3",
-    "orange-canvas-core>=0.1.29,<0.2a",
+    "orange-canvas-core>=0.1.30,<0.2a",
     'appnope; sys_platform=="darwin"'
 ]