grid.promise: do not always reload promise module

The reload part is mainly used for tests, module is reloaded if the promise file has changed. Here, __file__ ends with pyc when promise_path ends with py.

slapos/grid/promise/__init__.py

@@ -198,7 +198,7 @@ class PromiseProcess(Process):
       raise RuntimeError("RunPromise class is not a subclass of " \
         "GenericPromise class.")
 
-    if promise_module.__file__ != self.promise_path:
+    if 'py'.join(promise_module.__file__.rsplit('pyc')) != self.promise_path:
       # cached module need to be updated
       promise_module = reload_module(promise_module)
     # load extra parameters

[Nicolas Wavrant]

Wouldn't it fail if the path contains pyc ? If this code really does what I think it does (I may be wrong, I don't have a full picture of the context), using os.path.splitext will be safer.

For exemple :

>>> 'py'.join('aaa/bbb/pyc.pyc'.split('pyc'))
'aaa/bbb/py.py'
>>> os.path.splitext('aaa/bbb/pyc.pyc')
('aaa/bbb/pyc', '.pyc')

[Alain Takoudjou]

The file is loaded before as a python module so it's a .py. If the file is aaa/bbb/pyc.pyc it will raise before reaches this if condition. You can see bellow:

$ ls
__init__.py  __init__.pyc  test.py

then in a python console:

>>> import os, importlib
>>> promise_module = importlib.import_module(os.path.splitext("testpyc")[0])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: No module named testpyc

I try with test.pyc

$ mv testpyc test.pyc 


>>> promise_module = importlib.import_module(os.path.splitext("test.pyc")[0])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: Bad magic number in test.pyc

A file test.py is accepted

$ mv test.pyc test.py  
  
>>> promise_module = importlib.import_module(os.path.splitext("test.py")[0])
<module 'posixpath' from '/usr/lib/python2.7/posixpath.pyc'>
>>> promise_module.testing()
yes

$ ls test*
test.py  test.pyc

I can change anyway to use splitext if you think it's better.