Warn about upcoming change of the centerOption (#313)

* Added deprecate_kwarg decorator

* Added warning related to default centerOption deprecation

cadquery/cq.py

@@ -33,6 +33,8 @@
     exporters,
 )
 
+from .utils import deprecate_kwarg
+
 
 class CQContext(object):
     """
@@ -305,6 +307,7 @@ def toOCC(self):
 
         return self.objects[0].wrapped
 
+    @deprecate_kwarg("centerOption", "ProjectedOrigin")
     def workplane(
         self, offset=0.0, invert=False, centerOption="CenterOfMass", origin=None
     ):

cadquery/utils.py

@@ -0,0 +1,26 @@
+from functools import wraps
+from inspect import signature
+from warnings import warn
+
+
+class deprecate_kwarg:
+    def __init__(self, name, new_value):
+
+        self.name = name
+        self.new_value = new_value
+
+    def __call__(self, f):
+        @wraps(f)
+        def wrapped(*args, **kwargs):
+
+            f_sig_bound = signature(f).bind(*args, **kwargs)
+
+            if self.name not in f_sig_bound.kwargs:
+                warn(
+                    f"Default walue of {self.name} will change in next relase to {self.new_value}",
+                    FutureWarning,
+                )
+
+            return f(*args, **kwargs)
+
+        return wrapped