Fix a couple of make-temp-file races

* lisp/emacs-lisp/autoload.el (autoload--save-buffer):
* lisp/emacs-lisp/bytecomp.el (byte-compile-file):
Use make-temp-file, not make-temp-name, to avoid an unlikely race
that could lose data.  Remove the deletion hook as quickly as
possible after the file is renamed; though a race still remains
here, it is smaller than before.

2 files changed, 26 insertions, 24 deletions

diff --git a/lisp/emacs-lisp/autoload.el b/lisp/emacs-lisp/autoload.el
index 8fe94013700..4a9bd6d06b3 100644
--- a/lisp/emacs-lisp/autoload.el
+++ b/lisp/emacs-lisp/autoload.el
@@ -875,16 +875,16 @@ FILE's modification time."
   "Save current buffer to its file, atomically."
   ;; Copied from byte-compile-file.
   (let* ((version-control 'never)
-         (tempfile (make-temp-name buffer-file-name))
+         (tempfile (make-temp-file buffer-file-name))
          (kill-emacs-hook
           (cons (lambda () (ignore-errors (delete-file tempfile)))
                 kill-emacs-hook)))
     (write-region (point-min) (point-max) tempfile nil 1)
     (backup-buffer)
-    (rename-file tempfile buffer-file-name t)
-    (set-buffer-modified-p nil)
-    (set-visited-file-modtime)
-    (or noninteractive (message "Wrote %s" buffer-file-name))))
+    (rename-file tempfile buffer-file-name t))
+  (set-buffer-modified-p nil)
+  (set-visited-file-modtime)
+  (or noninteractive (message "Wrote %s" buffer-file-name)))
 
 (defun autoload-save-buffers ()
   (while autoload-modified-buffers
diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index fdd4276e4e7..5fa7389e431 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -1888,25 +1888,27 @@ The value is non-nil if there were no errors, nil if errors."
           (insert "\n")                 ; aaah, unix.
           (if (file-writable-p target-file)
               ;; We must disable any code conversion here.
-              (let* ((coding-system-for-write 'no-conversion)
-                     ;; Write to a tempfile so that if another Emacs
-                     ;; process is trying to load target-file (eg in a
-                     ;; parallel bootstrap), it does not risk getting a
-                     ;; half-finished file.  (Bug#4196)
-                     (tempfile (make-temp-name target-file))
-                     (kill-emacs-hook
-                      (cons (lambda () (ignore-errors (delete-file tempfile)))
-                            kill-emacs-hook)))
-                (write-region (point-min) (point-max) tempfile nil 1)
-                ;; This has the intentional side effect that any
-                ;; hard-links to target-file continue to
-                ;; point to the old file (this makes it possible
-                ;; for installed files to share disk space with
-                ;; the build tree, without causing problems when
-                ;; emacs-lisp files in the build tree are
-                ;; recompiled).  Previously this was accomplished by
-                ;; deleting target-file before writing it.
-                (rename-file tempfile target-file t)
+              (progn
+                (let* ((coding-system-for-write 'no-conversion)
+                       ;; Write to a tempfile so that if another Emacs
+                       ;; process is trying to load target-file (eg in a
+                       ;; parallel bootstrap), it does not risk getting a
+                       ;; half-finished file.  (Bug#4196)
+                       (tempfile (make-temp-file target-file))
+                       (kill-emacs-hook
+                        (cons (lambda () (ignore-errors
+                                           (delete-file tempfile)))
+                              kill-emacs-hook)))
+                  (write-region (point-min) (point-max) tempfile nil 1)
+                  ;; This has the intentional side effect that any
+                  ;; hard-links to target-file continue to
+                  ;; point to the old file (this makes it possible
+                  ;; for installed files to share disk space with
+                  ;; the build tree, without causing problems when
+                  ;; emacs-lisp files in the build tree are
+                  ;; recompiled).  Previously this was accomplished by
+                  ;; deleting target-file before writing it.
+                  (rename-file tempfile target-file t))
                 (or noninteractive (message "Wrote %s" target-file)))
             ;; This is just to give a better error message than write-region
             (let ((exists (file-exists-p target-file)))