(auto-mode-case-fold): New defcustom.

(set-auto-mode): If non-nil, perform second case-sensitive pass
through auto-mode-alist if first pass failed.

diff --git a/lisp/files.el b/lisp/files.el
index 78b0cdab2a54eba39e0c0bb16ba19b7d8b460655..4ad7ca2839ee03254025558cc899418bb139eaa8 100644 (file)
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -1876,6 +1876,16 @@ in that case, this function acts as if `enable-local-variables' were t."
   (if (fboundp 'ucs-set-table-for-input) ; don't lose when building
       (ucs-set-table-for-input)))
 
+(defcustom auto-mode-case-fold nil
+  "Non-nil means to try second pass through `auto-mode-alist'.
+This means that if the first case-sensitive search through the alist fails
+to find a matching major mode, a second case-insensitive search is made.
+On systems with case-insensitive file names, this variable is ignored,
+since only a single case-sensitive search through the alist is made."
+  :group 'files
+  :version "22.1"
+  :type 'boolean)
+
 (defvar auto-mode-alist
   ;; Note: The entries for the modes defined in cc-mode.el (c-mode,
   ;; c++-mode, java-mode and more) are added through autoload
@@ -2238,15 +2248,29 @@ only set the major mode, if that would change it."
              (setq name (file-name-sans-versions name))
              (while name
                ;; Find first matching alist entry.
-               (let ((case-fold-search
-                      (memq system-type '(vax-vms windows-nt cygwin))))
-                 (if (and (setq mode (assoc-default name auto-mode-alist
-                                                    'string-match))
-                          (consp mode)
-                          (cadr mode))
-                     (setq mode (car mode)
-                           name (substring name 0 (match-beginning 0)))
-                   (setq name)))
+               (setq mode
+                     (if (memq system-type '(vax-vms windows-nt cygwin))
+                         ;; System is case-insensitive.
+                         (let ((case-fold-search t))
+                           (assoc-default name auto-mode-alist
+                                          'string-match))
+                       ;; System is case-sensitive.
+                       (or
+                        ;; First match case-sensitively.
+                        (let ((case-fold-search nil))
+                          (assoc-default name auto-mode-alist
+                                         'string-match))
+                        ;; Fallback to case-insensitive match.
+                        (and auto-mode-case-fold
+                             (let ((case-fold-search t))
+                               (assoc-default name auto-mode-alist
+                                              'string-match))))))
+               (if (and mode
+                        (consp mode)
+                        (cadr mode))
+                   (setq mode (car mode)
+                         name (substring name 0 (match-beginning 0)))
+                 (setq name))
                (when mode
                  (set-auto-mode-0 mode keep-mode-if-same)))))))))