Subject: Re: bug#16733: messed up unicode chars in package description

From: Juanma Barranquero <[email-masked]>
Date: Sat, 22 Mar 2014 02:11:51 +0100

A possible fix for trunk, not the release branch.

Basically, the idea is to move most functionality from
url-insert-file-contents to a new url-insert-file-contents-internal,
which has an additional arg, a check function (possibly nil). That
function is called with the same parameters that
url-insert-file-contents plus the url buffer (with response codes,
etc.) returned by url-retrieve-synchronously. The original u-i-f-c
turns into a wrapper for u-i-f-c-internal, and
package--with-work-buffer can call u-i-f-c-internal and leverage
package-handle-response to check for errors.

(If we can assume that package-handle-response isn't used outside
package.el, a further simplification is possible.)

   J

=== modified file 'lisp/emacs-lisp/package.el'
--- lisp/emacs-lisp/package.el  2014-03-21 06:06:52 +0000
+++ lisp/emacs-lisp/package.el  2014-03-22 00:48:26 +0000
@@ -770,24 +770,20 @@
 and evaluates BODY while that buffer is current.  This work
 buffer is killed afterwards.  Return the last value in BODY."
   (declare (indent 2) (debug t))
-  `(let* ((http (string-match "\\`https?:" ,location))
-         (buffer
-          (if http
-              (url-retrieve-synchronously (concat ,location ,file))
-            (generate-new-buffer "*package work buffer*"))))
-     (prog1
-        (with-current-buffer buffer
-          (if http
-              (progn (package-handle-response)
-                     (re-search-forward "^$" nil 'move)
-                     (forward-char)
-                     (delete-region (point-min) (point)))
-            (unless (file-name-absolute-p ,location)
-              (error "Archive location %s is not an absolute file name"
-                     ,location))
-            (insert-file-contents (expand-file-name ,file ,location)))
-          ,@body)
-       (kill-buffer buffer))))
+  `(with-temp-buffer
+     (if (string-match-p "\\`https?:" ,location)
+        (progn
+          (require 'url-handlers)
+          (url-insert-file-contents-internal
+           (lambda (buffer &rest _)
+             (with-current-buffer buffer (package-handle-response)))
+           (concat ,location ,file))
+          (goto-char (point-min)))
+       (unless (file-name-absolute-p ,location)
+        (error "Archive location %s is not an absolute file name"
+               ,location))
+       (insert-file-contents (expand-file-name ,file ,location)))
+     ,@body))

 (defun package-handle-response ()
   "Handle the response from a `url-retrieve-synchronously' call.
@@ -1272,7 +1268,7 @@
                     (car archive)))))
       ;; Read the retrieved buffer to make sure it is valid (e.g. it
       ;; may fetch a URL redirect page).
-      (when (listp (read buffer))
+      (when (listp (read (current-buffer)))
        (make-directory dir t)
        (setq buffer-file-name (expand-file-name file dir))
        (let ((version-control 'never)
@@ -1531,8 +1527,7 @@
                        (setq readme-string (buffer-string))
                        t))
                 (error nil))
-              (let ((coding (detect-coding-string readme-string t)))
-                (insert (decode-coding-string readme-string coding t))))
+              (insert readme-string))
              ((file-readable-p readme)
               (insert-file-contents readme)
               (goto-char (point-max))))))))

=== modified file 'lisp/url/url-handlers.el'
--- lisp/url/url-handlers.el    2014-01-01 07:43:34 +0000
+++ lisp/url/url-handlers.el    2014-03-22 00:53:21 +0000
@@ -290,11 +290,12 @@
       (insert data))
     (list (length data) charset)))

-;;;###autoload
-(defun url-insert-file-contents (url &optional visit beg end replace)
+(defun url-insert-file-contents-internal (check url &optional visit
beg end replace)
   (let ((buffer (url-retrieve-synchronously url)))
-    (if (not buffer)
-       (error "Opening input file: No such file or directory, %s" url))
+    (when check
+      (unwind-protect
+         (funcall check buffer url visit beg end replace)
+       (when buffer (kill-buffer))))
     (if visit (setq buffer-file-name url))
     (save-excursion
       (let* ((start (point))
@@ -308,6 +309,14 @@
           ;; usual heuristic/rules that we apply to files.
           (decode-coding-inserted-region start (point) url visit beg
end replace))
         (list url (car size-and-charset))))))
+
+;;;###autoload
+(defun url-insert-file-contents (url &optional visit beg end replace)
+  (url-insert-file-contents-internal
+   (lambda (buffer url &rest _ignore)
+     (unless buffer
+       (error "Opening input file: No such file or directory, %s" url)))
+   url visit beg end replace))
 (put 'insert-file-contents 'url-file-handlers 'url-insert-file-contents)

 (defun url-file-name-completion (url directory &optional predicate)