bug#5126: 23.1; checkdoc-comment-style-hooks stops at first error

[Kevin Ryde <user42@zip.com.au>]

checkdoc-comment-style-hooks is run by checkdoc-file-comments-engine
with run-hook-with-args-until-success, which means if one of the hook
functions returns an error string (as described in the hook's docstring)
then no further functions are run.

I hoped the hook functions would instead run like the builtin checks of
checkdoc-file-comments-engine,

    (setq err (or (some check)
                  err))

so that all checks are always run, with an error reported if any one of
them reports an error.

Or alternately perhaps I misunderstand the docstring of
checkdoc-comment-style-hooks, and that a "problem discovered" means
something fatal and unrecoverable, or something, and that hook functions
should almost always return nil no matter what they find.


I threw down the few lines below for a hook run which returns the last
true value, but I'm not sure I like it much.  An alternative to picking
out a list of functions from a hook might be a
"run-hook-with-accumulator-function" or even a "map-hook" -- unless that
exists already.

(defun checkdoc-run-hooks-last-true (hookvar)
  "Run hooks in HOOKVAR and return the last true value."
  (let (ret)
    (dolist (func (checkdoc-hook-functions hookvar))
      (setq ret (or (funcall func) ret)))))

(defun checkdoc-hook-functions (hookvar)
  "Return a list of functions HOOKVAR should run.
HOOKVAR can be a single function or list of functions, the return
is always a list.  `t' in a buffer-local value means use the
global `default-value' at that point, and it can likewise be a
function or list."
  (let ((hooks (symbol-value hookvar)))
    (if (and hooks
	     ;; same test as run_hook_with_args()
	     (or (not (consp hooks))
		 (eq 'lambda (car hooks))))
	(list hooks) ;; single function listified

      ;; expand `t' to global value
      (apply 'append
	     (mapcar (lambda (func)
		       (if (eq t func)
			   (let ((global (default-value hookvar)))
			     ;; same test as run_hook_with_args()
			     (if (or (not (consp global))
				     (eq 'lambda (car global)))
				 (list global)
			       global))
			 (list func)))
		     hooks)))))




In GNU Emacs 23.1.1 (i486-pc-linux-gnu, GTK+ Version 2.16.5)
 of 2009-09-14 on raven, modified by Debian
configured using `configure  '--build=i486-linux-gnu' '--host=i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.1/leim' '--with-x=yes' '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars' 'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -g -O2' 'LDFLAGS=-g' 'CPPFLAGS=''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_AU
  value of $XMODIFIERS: nil
  locale-coding-system: iso-latin-1-unix
  default-enable-multibyte-characters: t