[IPython-dev] Fixing silent failures with IPython Notebook / uuid on Cygwin64

[Aron Ahmadia]

A better fix that I missed is this patch from Evgeny Sologubov

diff -r 4a318a45c4c3 Lib/uuid.py
--- a/Lib/uuid.py   Mon Aug 19 13:07:18 2013 -0400
+++ b/Lib/uuid.py   Mon Aug 19 21:41:08 2013 +0400
@@ -429,6 +429,8 @@
             _uuid_generate_random = lib.uuid_generate_random
         if hasattr(lib, 'uuid_generate_time'):
             _uuid_generate_time = lib.uuid_generate_time
+            if _uuid_generate_random is not None:
+                break  # found everything we were looking for

     # The uuid_generate_* functions are broken on MacOS X 10.5, as noted
     # in issue #8621 the function generates the same sequence of values

Happy computing,
Aron

On Mon, Sep 30, 2013 at 2:26 PM, Aron Ahmadia <aron at ahmadia.net> wrote:
> Just a heads up for anybody who is trying to do development in Cygwin64.
>
> First off, you will need to follow the instructions here for getting
> ZMQ/PYZMQ:
>
> https://github.com/zeromq/pyzmq/issues/113
>
> If you are trying to run the notebook, you may encounter silent failures
> when running IPython Notebook from the command line:
>
> $ ipython notebook
>
> (Simply exits with no messages/errors)
>
> This is coming from a segfault in the Cygwin64 Python uuid module.  I tried
> to follow the instructions here:
> http://stackoverflow.com/questions/18947163/uuid-python-import-fails-on-cygwin-64bits
> and here: http://bugs.python.org/file20685/issue11063.patch but this didn't
> fix the crash.
>
> My stop-gap solution is to disable the call to _uuid_generate in uuid4
> post-patch.  This is reasonably safe, and just uses a different random
> number generator instead of the system-provided uuid function.
>
> def uuid4():
>     """Generate a random UUID."""
>
>     # When the system provides a version-4 UUID generator, use it.
>
> +    # AA disabling _uuid_generate
> +    uuid_generate_random = None
> -    uuid_generate_random = _uuid_generate("uuid_generate_random")
>
> The CPython and Cygwin folks appear to be aware of this issue, but since it
> took some of my time to debug, I'm hoping this will help others encountering
> similar problems in the future.
>
> After switching away from a GitHub release build, I've got IPython Notebook
> and the majority of its dependencies building from source using HashDist on
> Cygwin64 with a few things coming from the system, such as the broken Python
> patched above.
>
> Happy coding.
>
> A
>
>
>
>