`with-output-to-string' leaks buffers

[Romain Francoise]

Shouldn't `with-output-to-string' reap the temporary buffer it
creates even if the code it wraps exits nonlocally?

(git.el installs a function in `after-save-hook' which uses this
macro around code that signals an error, and as a result I had a
little more than 250 *string-output* buffers slowing things down
after a few days of uptime...)

2008-09-19  Romain Francoise  <address@hidden>

        * subr.el (with-output-to-string): Make sure that the temporary
        buffer gets killed.

Index: lisp/subr.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/subr.el,v
retrieving revision 1.606
diff -u -r1.606 subr.el
--- lisp/subr.el        7 Sep 2008 09:15:43 -0000       1.606
+++ lisp/subr.el        19 Sep 2008 21:56:40 -0000
@@ -2586,12 +2586,13 @@
   (declare (indent 0) (debug t))
   `(let ((standard-output
          (get-buffer-create (generate-new-buffer-name " *string-output*"))))
-     (let ((standard-output standard-output))
-       ,@body)
-     (with-current-buffer standard-output
-       (prog1
-          (buffer-string)
-        (kill-buffer nil)))))
+     (unwind-protect
+        (progn
+          (let ((standard-output standard-output))
+            ,@body)
+          (with-current-buffer standard-output
+            (buffer-string)))
+       (kill-buffer standard-output))))
 
 (defmacro with-local-quit (&rest body)
   "Execute BODY, allowing quits to terminate BODY but not escape further.