GNU bug report logs -
#65797
`buffer-match-p` should not use `func-arity`
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Reported by: Joseph Turner <joseph <at> breatheoutbreathe.in>
Date: Thu, 7 Sep 2023 07:56:02 UTC
Severity: normal
Found in version 29.0.92
Done: Stefan Monnier <monnier <at> iro.umontreal.ca>
Bug is archived. No further changes may be made.
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Message #115 received at 65797 <at> debbugs.gnu.org (full text, mbox):
Stefan Monnier <monnier <at> iro.umontreal.ca> writes:
>> I am in favor of this solution as well.
>
> Then how 'bout something like the patch below which changes the
> `&optional` into an `&rest` but tries to preserve compatibility with the
> old calling convention.
>
>
> Stefan
>
>
> diff --git a/lisp/subr.el b/lisp/subr.el
> index e88815fa58c..06c9923b525 100644
> --- a/lisp/subr.el
> +++ b/lisp/subr.el
> @@ -7295,13 +7292,13 @@ string-lines
> (setq start (length string)))))
> (nreverse lines))))
>
> -(defun buffer-match-p (condition buffer-or-name &optional arg)
> +(defun buffer-match-p (condition buffer-or-name &rest args)
> "Return non-nil if BUFFER-OR-NAME matches CONDITION.
> CONDITION is either:
> - the symbol t, to always match,
> - the symbol nil, which never matches,
> - a regular expression, to match a buffer name,
> -- a predicate function that takes BUFFER-OR-NAME and ARG as
> +- a predicate function that takes BUFFER-OR-NAME plus ARGS as
> arguments, and returns non-nil if the buffer matches,
> - a cons-cell, where the car describes how to interpret the cdr.
> The car can be one of the following:
> @@ -7326,9 +7323,18 @@ buffer-match-p
> ((pred stringp)
> (string-match-p condition (buffer-name buffer)))
> ((pred functionp)
> - (if (eq 1 (cdr (func-arity condition)))
> - (funcall condition buffer-or-name)
> - (funcall condition buffer-or-name arg)))
> + (if (cdr args)
> + ;; More than 1 argument: no need for
> + ;; Emacs-29 backward compatibility!
> + (apply condition buffer-or-name args)
> + (condition-case err
> + (apply condition buffer-or-name args)
> + (wrong-number-of-arguments
> + ;; Backward compatibility with Emacs-29 semantics.
> + (message "Trying obsolete calling convention for: %S"
> + Condition)
> + (apply condition buffer-or-name
> + (if args '(nil) nil))))))
> (`(major-mode . ,mode)
> (eq
> (buffer-local-value 'major-mode buffer)
> @@ -7350,17 +7356,17 @@ buffer-match-p
> (throw 'match t)))))))
> (funcall match (list condition))))
At first, I was concerned that the condition-case would mess up error
handling in user code, but all 9 permutations give the expected results:
(let ((condition
(lambda (buf) t)
;; (lambda (buf arg1) t)
;; (lambda (buf arg1 arg2) t)
))
(condition-case err
(buffer-match-p condition (current-buffer)
;; 'arg1
;; 'arg2
)
(wrong-number-of-arguments
"Caught")))
> -(defun match-buffers (condition &optional buffers arg)
> +(defun match-buffers (condition &optional buffers &rest args)
> "Return a list of buffers that match CONDITION, or nil if none match.
> See `buffer-match-p' for various supported CONDITIONs.
> By default all buffers are checked, but the optional
> argument BUFFERS can restrict that: its value should be
> an explicit list of buffers to check.
> -Optional argument ARG is passed to `buffer-match-p', for
> +Optional arguments ARGS are passed to `buffer-match-p', for
> predicate conditions in CONDITION."
> (let (bufs)
> (dolist (buf (or buffers (buffer-list)))
> - (when (buffer-match-p condition (get-buffer buf) arg)
> + (when (apply #'buffer-match-p condition (get-buffer buf) args)
> (push buf bufs)))
> bufs))
>
This bug report was last modified 1 year and 217 days ago.
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