bug#19645: 25.0.50; Recent EIEIO changes broke helm: Lisp error: (cl-no-next-method helm--setup-source...

[Stefan Monnier <monnier@iro.umontreal.ca>]

>   helm-bbdb.el:22:1:Error: No next method for %S: helm--setup-source,
>   nil, [eieio-class-tag--helm-type-file...

It appears that you're calling helm--setup-source with an object of type
helm-type-file, but the only method that matches is a ":before" method, so
after running the before method, you get an error because there's
no primary.

IIUC the error should be `cl-no-primary-method' instead of
`cl-no-next-method' (according to
http://www.cliki.net/Proposed%20ANSI%20Revisions%20and%20Clarifications).

From what I can tell, the older EIEIO code just silently did nothing
in this case, treating the missing primary as a function that just
returns nil, but I think this is a mistake.

I'm not sure how to preserve the compatibility with this mistake.
I'll see if I can come up with something, but in any case I think you
should fix Helm by making sure there is some primary method defined in
this case as well.


        Stefan