Waf file creation will now require Python 3

ChangeLog

@@ -1,3 +1,7 @@
+- Remove waflib.Runner.PriorityTasks.appendleft
+- Remove waflib.Task.TaskBase
+- Remove the upper class of waflib.Task.Task (metaclasses)
+
 NEW IN WAF 2.0.19
 -----------------
 * Fix negative values for -j #2256

TODO

@@ -5,8 +5,5 @@ Waf 2.1
 - Fix the circular imports ccroot<->c_config.py
 - Remove superfluous *k in ctx.load() and other unused parameters
   Ensure conf.load() has the same interface as ctx.load()
-- Remove waflib.Runner.PriorityTasks.appendleft
-- Remove waflib.Task.TaskBase
-- Remove the upper class of waflib.Task.Task (metaclasses)
 - Ordered_iter_dict in python 3.7
 - Change _add_task to add_task in Runner.py

waf-light

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # encoding: latin-1
 # Thomas Nagy, 2005-2018
 #

waflib/Runner.py

@@ -43,9 +43,6 @@ class PriorityTasks(object):
 		self.lst = []
 	def append(self, task):
 		heapq.heappush(self.lst, task)
-	def appendleft(self, task):
-		"Deprecated, do not use"
-		heapq.heappush(self.lst, task)
 	def pop(self):
 		return heapq.heappop(self.lst)
 	def extend(self, lst):

waflib/Task.py

@@ -132,10 +132,7 @@ class store_task_type(type):
 			# be creative
 			getattr(cls, 'register', classes)[name] = cls
 
-evil = store_task_type('evil', (object,), {})
-"Base class provided to avoid writing a metaclass, so the code can run in python 2.6 and 3.x unmodified"
-
-class Task(evil):
+class Task(metaclass=store_task_type):
 	"""
 	Task objects represents actions to perform such as commands to execute by calling the `run` method.
 
@@ -1350,9 +1347,6 @@ def deep_inputs(cls):
 	cls.sig_explicit_deps = sig_explicit_deps
 	return cls
 
-TaskBase = Task
-"Provided for compatibility reasons, TaskBase should not be used"
-
 class TaskSemaphore(object):
 	"""
 	Task semaphores provide a simple and efficient way of throttling the amount of

waflib/fixpy2.py

@@ -62,3 +62,6 @@ def r4(code):
 def r5(code):
 	return code.replace("('Execution failure: %s'%str(e),ex=e)", "('Execution failure: %s'%str(e),ex=e),None,sys.exc_info()[2]")
 
+@subst('Task.py')
+def r6(code):
+	return code.replace('metaclass=store_task_type', "store_task_type('evil', (object,), {})")