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bug#8387: 24.0.50; `run-hook-with-args' return value has changed
From: |
Stefan Monnier |
Subject: |
bug#8387: 24.0.50; `run-hook-with-args' return value has changed |
Date: |
Thu, 31 Mar 2011 11:02:49 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) |
> (defun foo (arg) 'test) C-j
> (defvar foo-hook '(foo)) C-j
> (run-hook-with-args 'foo-hook 'foo) C-j
> In the past, this would return 'test instead of nil. This breaks some
[...]
> I don't have time to test this right now, but I would guess this started
> happening in the following commit:
[...]
> (run_hook_with_args): Call each function through a `funcall' argument.
> Remove `cond' argument, now redundant.
> (Frun_hooks, Frun_hook_with_args, Frun_hook_with_args_until_success)
> (Frun_hook_with_args_until_failure): Adjust accordingly.
No doubt it's the origin of the new behavior.
But note that the above change has not touched the docstring of
run-hook-with-args which says:
It is best not to depend on the value returned by `run-hook-with-args',
as that may change.
Looking at the BBDB code, I think we don't need to try and accomodate it
because it is fundamentally broken, not just because of the above
docstring warning:
;; Hysterical Raisins: This is a function, not a hook. In order to
;; make this hook a hook, we'll quietly convert a single function
;; into a hook list. We should really warn the user that we're
;; doing this, and advise them to update their configuration
;; accordingly. For the release, maybe.
(if (functionp bbdb-canonicalize-net-hook)
(setq bbdb-canonicalize-net-hook (list bbdb-canonicalize-net-hook)))
;; Now, do the hook run. Note, if you mess up, it's possible that
;; BBDB will get stuck here oscillating between various definitions
;; of the canonical address.
(while (not (equal net (setq net (run-hook-with-args
'bbdb-canonicalize-net-hook net)))))
So bbdb-canonicalize-net-hook can start as a single function or a list
of functions. But the code is explicit about wanting a list of
functions. Now if this list contains N>1 function, then
run-hook-with-args has to call all those functions and discard at least
N-1 of the results. I.e. only one of the functions on
bbdb-canonicalize-net-hook can work (in Emacs-23, one of them happened
to work, and on the current trunk, none of them work).
Stefan