[core] avoid direct includes to PySide2

meshroom/common/__init__.py

@@ -8,13 +8,14 @@
 BaseObject = None
 Variant = None
 VariantList = None
+JSValue = None
 
 if meshroom.backend == meshroom.Backend.PYSIDE:
     # PySide types
-    from .qt import DictModel, ListModel, Slot, Signal, Property, BaseObject, Variant, VariantList
+    from .qt import DictModel, ListModel, Slot, Signal, Property, BaseObject, Variant, VariantList, JSValue
 elif meshroom.backend == meshroom.Backend.STANDALONE:
     # Core types
-    from .core import DictModel, ListModel, Slot, Signal, Property, BaseObject, Variant, VariantList
+    from .core import DictModel, ListModel, Slot, Signal, Property, BaseObject, Variant, VariantList, JSValue
 
 
 class _BaseModel:

meshroom/common/core.py

@@ -146,3 +146,4 @@ def parent(self):
 BaseObject = CoreObject
 Variant = object
 VariantList = object
+JSValue = None

meshroom/common/qt.py

@@ -1,4 +1,4 @@
-from PySide2 import QtCore
+from PySide2 import QtCore, QtQml
 
 
 class QObjectListModel(QtCore.QAbstractListModel):
@@ -374,3 +374,4 @@ def sort(self):
 BaseObject = QtCore.QObject
 Variant = "QVariant"
 VariantList = "QVariantList"
+JSValue = QtQml.QJSValue

meshroom/core/desc.py

@@ -1,10 +1,9 @@
-from meshroom.common import BaseObject, Property, Variant, VariantList
+from meshroom.common import BaseObject, Property, Variant, VariantList, JSValue
 from meshroom.core import pyCompatibility
 from enum import Enum  # available by default in python3. For python2: "pip install enum34"
 import math
 import os
 import psutil
-import PySide2
 import ast
 
 class Attribute(BaseObject):
@@ -69,7 +68,7 @@ def __init__(self, elementDesc, name, label, description, group='allParams', adv
     joinChar = Property(str, lambda self: self._joinChar, constant=True)
 
     def validateValue(self, value):
-        if isinstance(value, PySide2.QtQml.QJSValue):
+        if JSValue is not None and isinstance(value, JSValue):
             # Note: we could use isArray(), property("length").toInt() to retrieve all values
             raise ValueError("ListAttribute.validateValue: cannot recognize QJSValue. Please, use JSON.stringify(value) in QML.")
         if isinstance(value, pyCompatibility.basestring):
@@ -105,7 +104,7 @@ def __init__(self, groupDesc, name, label, description, group='allParams', advan
 
     def validateValue(self, value):
         """ Ensure value is compatible with the group description and convert value if needed. """
-        if isinstance(value, PySide2.QtQml.QJSValue):
+        if JSValue is not None and isinstance(value, JSValue):
             # Note: we could use isArray(), property("length").toInt() to retrieve all values
             raise ValueError("GroupAttribute.validateValue: cannot recognize QJSValue. Please, use JSON.stringify(value) in QML.")
         if isinstance(value, pyCompatibility.basestring):