Propagate errors with context management

[zshaheen]

At lines 1260 here, we should have something like this:

def __exit__(self, type, value, traceback):
    if type is None:
        self.close()
    else:
        return False

Returning False will propagate any exceptions raised by the with block below:

with cdms2.open('something.nc') as f:
    # this is the with block

[zshaheen]

@doutriaux1 @dnadeau4 thought?

[doutriaux1]

@zshaheen sounds right, do you mind submitting a PR?

[dnadeau4]

@zshaheen I put your code in and create a test for it. I tried to make it failed with and without your code and got the same error message. So I did not understand what it does more.

It is in my python3merge branch and all tests passed.

[doutriaux1]

@zshaheen can you provide a test for it please? Or a link to why this is important, @dnadeau4 and I can make a test from such a link as well.

[zshaheen]

@doutriaux1 Sure, I'll get to this this week.