bug#9044: 24.0.50; File mode specification error: (error "Malformed -*- line")

[Chong Yidong]

Juri Linkov <juri@jurta.org> writes:

>> How about just adding the common ones -- jpeg?, tiff?, png, gif.  That
>> will take care of 99% of the problems.
>
> There are many other binary formats that may contain "-*-" in the
> first line.  For example, it's impossible to visit TGA files in Emacs
> because they contain a lot of "-*-".

I propose two fixes: (1) Adding some common image types to
inhibit-first-line-modes-regexps, and (2) changing
hack-local-variables-prop-line to return nil instead of signalling an
error for the "Malformed mode line" case.

Does anyone see a problem with this approach (in particular (2))?

=== modified file 'lisp/files.el'
*** lisp/files.el       2011-09-12 20:45:56 +0000
--- lisp/files.el       2011-09-17 21:56:13 +0000
***************
*** 2461,2467 ****
  
  See also `auto-mode-alist'.")
  
! (defvar inhibit-first-line-modes-regexps (mapcar 'purecopy '("\\.tar\\'" 
"\\.tgz\\'"))
    "List of regexps; if one matches a file name, don't look for `-*-'.")
  
  (defvar inhibit-first-line-modes-suffixes nil
--- 2461,2469 ----
  
  See also `auto-mode-alist'.")
  
! (defvar inhibit-first-line-modes-regexps
!   (mapcar 'purecopy '("\\.tar\\'" "\\.tgz\\'" "\\.tiff?\\'"
!                     "\\.gif\\'" "\\.png\\'" "\\.jpe?g\\'"))
    "List of regexps; if one matches a file name, don't look for `-*-'.")
  
  (defvar inhibit-first-line-modes-suffixes nil
***************
*** 2952,2961 ****
  and VAL is the specified value.  Ignores any specification for
  `mode:' and `coding:' (which should have already been handled
  by `set-auto-mode' and `set-auto-coding', respectively).
! Throws an error if the -*- line is malformed.
  
  If MODE-ONLY is non-nil, just returns the symbol specifying the
  mode, if there is one, otherwise nil."
    (save-excursion
      (goto-char (point-min))
      (let ((end (set-auto-mode-1))
--- 2954,2964 ----
  and VAL is the specified value.  Ignores any specification for
  `mode:' and `coding:' (which should have already been handled
  by `set-auto-mode' and `set-auto-coding', respectively).
! Return nil if the -*- line is malformed.
  
  If MODE-ONLY is non-nil, just returns the symbol specifying the
  mode, if there is one, otherwise nil."
+   (catch 'fail
    (save-excursion
      (goto-char (point-min))
      (let ((end (set-auto-mode-1))
***************
*** 2974,2981 ****
             (while (and (or (not mode-only)
                             (not result))
                         (< (point) end))
!              (or (looking-at "[ \t]*\\([^ \t\n:]+\\)[ \t]*:[ \t]*")
!                  (error "Malformed -*- line"))
               (goto-char (match-end 0))
               ;; There used to be a downcase here,
               ;; but the manual didn't say so,
--- 2977,2985 ----
             (while (and (or (not mode-only)
                             (not result))
                         (< (point) end))
!              (unless (looking-at "[ \t]*\\([^ \t\n:]+\\)[ \t]*:[ \t]*")
!                (message "Malformed mode-line")
!                (throw 'fail nil))
               (goto-char (match-end 0))
               ;; There used to be a downcase here,
               ;; but the manual didn't say so,
***************
*** 3005,3011 ****
                                       val) result)
                         (error nil))))
                 (skip-chars-forward " \t;")))
!            result)))))
  
  (defun hack-local-variables-filter (variables dir-name)
    "Filter local variable settings, querying the user if necessary.
--- 3009,3015 ----
                                       val) result)
                         (error nil))))
                 (skip-chars-forward " \t;")))
!            result))))))
  
  (defun hack-local-variables-filter (variables dir-name)
    "Filter local variable settings, querying the user if necessary.