Only set schedule conditionally

theano/compile/debugmode.py

@@ -1551,7 +1551,8 @@ class _Linker(gof.link.LocalLinker):
         super(gof.LocalLinker, self).__init__()
         self.fgraph = None
         self.maker = maker
-        self.schedule = schedule or self.schedule
+        if schedule:
+            self.schedule = schedule
 
     def accept(self, fgraph, no_recycling=None):
         if no_recycling is None:

theano/gof/cc.py

@@ -404,7 +404,8 @@ class CLinker(link.Linker):
 
     def __init__(self, schedule=None):
         self.fgraph = None
-        self.schedule = schedule or self.schedule
+        if schedule:
+            self.schedule = schedule
 
     def accept(self, fgraph, no_recycling=None):
         """WRITEME"""
@@ -1405,7 +1406,8 @@ class OpWiseCLinker(link.LocalLinker):
         self.fallback_on_perform = fallback_on_perform
         self.nice_errors = nice_errors
         self.allow_gc = allow_gc
-        self.schedule = schedule or self.schedule
+        if schedule:
+            self.schedule = schedule
 
     def accept(self, fgraph, no_recycling=None):
         if no_recycling is None:
@@ -1550,7 +1552,8 @@ class DualLinker(link.Linker):
         """
         self.fgraph = None
         self.checker = checker
-        self.schedule = schedule or self.schedule
+        if schedule:
+            self.schedule = schedule
 
     def accept(self, fgraph, no_recycling=None):
         if no_recycling is None:

theano/gof/link.py

@@ -424,7 +424,8 @@ class PerformLinker(LocalLinker):
         #TODO: set allow_gc = True by default, when it works with the OpWiseCLinker
         self.fgraph = None
         self.allow_gc = allow_gc
-        self.schedule = schedule or self.schedule
+        if schedule:
+            self.schedule = schedule
 
     def accept(self, fgraph, no_recycling=None):
         """

theano/gof/vm.py

@@ -538,7 +538,8 @@ class VM_Linker(link.LocalLinker):
         self.callback = callback
         self.lazy = lazy
         self.updated_vars = {}
-        self.schedule = schedule or self.schedule
+        if schedule:
+            self.schedule = schedule
 
     def accept(self, fgraph, no_recycling=None):
         """