[PATCH] debugshell: disable demand importer when importing debugger

[Sean Farley]

Gregory Szorc <gregory.szorc at gmail.com> writes:

> # HG changeset patch
> # User Gregory Szorc <gregory.szorc at gmail.com>
> # Date 1452564998 28800
> #      Mon Jan 11 18:16:38 2016 -0800
> # Node ID 7e2276ca61d80c04e8838e502f42304be2e70aa9
> # Parent  4571c0b383378f5eec5189e3a39c672a169ce566
> debugshell: disable demand importer when importing debugger
>
> For reasons I can't explain (but likely have something to do with a
> combination of __import__ inferring default values for arguments and
> the demand importer mechanism further assuming defaults), the demand
> importer isn't playing well with IPython. Without this patch, we get
> a failure "ValueError: Attempted relative import in non-package" when
> attempting to import "IPython." The stack has numerous demandimport
> calls on it and adding "IPython" to the exclude list in demandimport
> isn't enough to make the problem go away, which means the issue is
> likely somewhere in the bowells of IPython. It's easier to just disable
> the demand importer when importing the debugger.

Sweet! This fixes the issue for me.