[bitbake][PATCH] lib/bb/build.py: Raise proper KeyError if function does not exist

[Mike Looijmans <mike.looijmans@topic.nl>]

If one adds the following line to an image recipe without defining
the function:
ROOTFS_POSTPROCESS_COMMAND += "rootfs_funky_stuff;"
bitbake will terminate with a cryptic error message:
AttributeError: 'NoneType' object has no attribute 'get'

To inform the user of what bitbake wasn't able to find, raise a KeyError
exception denoting the function name before that happens. This changes the
message to the much more useful:
KeyError: 'rootfs_funky_stuff'

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
---
 lib/bb/build.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/bb/build.py b/lib/bb/build.py
index c4c8aeb..5bc18c1 100644
--- a/lib/bb/build.py
+++ b/lib/bb/build.py
@@ -194,6 +194,8 @@ def exec_func(func, d, dirs = None, pythonexception=False):
         oldcwd = None
 
     flags = d.getVarFlags(func)
+    if flags is None:
+        raise KeyError(func)
     cleandirs = flags.get('cleandirs')
     if cleandirs:
         for cdir in d.expand(cleandirs).split():
-- 
1.9.1