Improve lib.polyConstraint performance when Select tool is not the active tool context

openpype/hosts/maya/api/lib.py

@@ -745,6 +745,33 @@ def namespaced(namespace, new=True):
         cmds.namespace(set=original)
 
 
+@contextlib.contextmanager
+def maintained_selection_api():
+    """Maintain selection using the Maya Python API.
+
+    Warning: This is *not* added to the undo stack.
+
+    """
+    original = om.MGlobal.getActiveSelectionList()
+    try:
+        yield
+    finally:
+        om.MGlobal.setActiveSelectionList(original)
+
+
+@contextlib.contextmanager
+def tool(context):
+    """Set a tool context during the context manager.
+
+    """
+    original = cmds.currentCtx()
+    try:
+        cmds.setToolTo(context)
+        yield
+    finally:
+        cmds.setToolTo(original)
+
+
 def polyConstraint(components, *args, **kwargs):
     """Return the list of *components* with the constraints applied.
 
@@ -763,17 +790,25 @@ def polyConstraint(components, *args, **kwargs):
     kwargs.pop('mode', None)
 
     with no_undo(flush=False):
-        with maya.maintained_selection():
-            # Apply constraint using mode=2 (current and next) so
-            # it applies to the selection made before it; because just
-            # a `maya.cmds.select()` call will not trigger the constraint.
-            with reset_polySelectConstraint():
-                cmds.select(components, r=1, noExpand=True)
-                cmds.polySelectConstraint(*args, mode=2, **kwargs)
-                result = cmds.ls(selection=True)
-                cmds.select(clear=True)
-
-    return result
+        # Reverting selection to the original selection using
+        # `maya.cmds.select` can be slow in rare cases where previously
+        # `maya.cmds.polySelectConstraint` had set constrain to "All and Next"
+        # and the "Random" setting was activated. To work around this we
+        # revert to the original selection using the Maya API. This is safe
+        # since we're not generating any undo change anyway.
+        with tool("selectSuperContext"):
+            # Selection can be very slow when in a manipulator mode.
+            # So we force the selection context which is fast.
+            with maintained_selection_api():
+                # Apply constraint using mode=2 (current and next) so
+                # it applies to the selection made before it; because just
+                # a `maya.cmds.select()` call will not trigger the constraint.
+                with reset_polySelectConstraint():
+                    cmds.select(components, r=1, noExpand=True)
+                    return cmds.polySelectConstraint(*args,
+                                                     mode=2,
+                                                     returnSelection=True,
+                                                     **kwargs)
 
 
 @contextlib.contextmanager