mm-charset-to-coding-system and mm-charset-synonym-alist

[Stefan Monnier]

Is there any good reason why mm-charset-to-coding-system only looks up
mm-charset-synonym-alist after checking mm-coding-system-p?

I'm being annoyed with email encoded in windows-1252 but labelled as latin-1
and figured that I could simply put

   ;; Since windows-1252 is a superset of latin-1 and some email encoded in
   ;; windows-1252 are labelled as latin-1, let's just always use windows-1252
   ;; whenever the label says latin-1.
   (add-to-list 'mm-charset-synonym-alist '(iso-8859-1 . windows-1252))

in my .gnus, but it didn't work because mm-charset-synonym-alist is not
consulted if the charset label says "iso-8859-1" because there is
a coding-system called "iso-8859-1".

So I suggest the patch below,
Any objection?


        Stefan


--- orig/lisp/gnus/mm-util.el
+++ mod/lisp/gnus/mm-util.el
@@ -421,18 +421,18 @@
    ;; ascii
    ((eq charset 'us-ascii)
     'ascii)
+   ;; Translate invalid charsets.
+   ((let ((cs (cdr (assq charset mm-charset-synonym-alist))))
+      (and cs (mm-coding-system-p cs) cs)))
    ;; Check to see whether we can handle this charset.  (This depends
    ;; on there being some coding system matching each `mime-charset'
    ;; property defined, as there should be.)
    ((and (mm-coding-system-p charset)
-;;; Doing this would potentially weed out incorrect charsets.
-;;;     charset
-;;;     (eq charset (coding-system-get charset 'mime-charset))
+        ;; Doing this would potentially weed out incorrect charsets.
+        ;;      charset
+        ;;      (eq charset (coding-system-get charset 'mime-charset))
         )
     charset)
-   ;; Translate invalid charsets.
-   ((let ((cs (cdr (assq charset mm-charset-synonym-alist))))
-      (and cs (mm-coding-system-p cs) cs)))
    ;; Try to find ones that are spelled similarly.
    ((let ((cs (replace-regexp-in-string "[-_]" "" (symbol-name charset)))
          res)