[matplotlib-devel] A small fix for backend specification...

[Fernando P. <fpe...@gm...>]

Hi folks,

I'd like to know if the fix below looks reasonable to you, this is a
diff against current svn trunk:

dreamweaver[matplotlib]> svn diff
Index: __init__.py
===================================================================
--- __init__.py	(revision 8656)
+++ __init__.py	(working copy)
@@ -880,10 +880,14 @@
     if 'matplotlib.backends' in sys.modules:
         if warn: warnings.warn(_use_error_msg)
         return
-    arg = arg.lower()
     if arg.startswith('module://'):
         name = arg
     else:
+        # For non-module backends, normalize name to lowercase.  Note that this
+        # must NOT be done to module backends, because those need to be valid
+        # Python module specifications that can be imported, and Python module
+        # names *are* case sensitive.
+        arg = arg.lower()
         be_parts = arg.split('.')
         name = validate_backend(be_parts[0])
         if len(be_parts) > 1:

##### END PATCH

I hope the comments explain clearly enough the problem.  For a bit of
context, this is biting us in ipython where we're building a custom
backend for Qt terminals that inline mpl figures (very neat [1]), but
our backend's name is module://IPython.zmq.pylab.backend_payload_svg.
If you lowercase that, it won't import later.  I know we shouldn't
have called IPython's module with that funny capitalization, but it's
a bit late to change now, I'm afraid.

Do you foresee any problems with the above change?

If everyone OK's it, I'm happy to commit it, but I won't do anything
until others better informed than I reply.

Regards,

f

[1] teaser for the curious:
http://fperez.org/tmp/ipython_qt_pylab.png.  All code is in the
'newkernel' github branch.  Special credits to Evan Patterson from
Enthought, the Qt brains behind the magic.