* (diff-process-setup): New function, sets up the

compilation-exit-message-function so that it works with both
asynchronous and synchronous sub-processes.
(diff): Bind compilation-exit-message-function.  Run
compilation-finish-function when compile-internal returns if async
processes aren't supported.

diff --git a/lisp/diff.el b/lisp/diff.el
index 2ec0a8b14bde15a99f2a68fa46639f57b588ffce..73b783a576ec23aa0d06190ee7db40c24416ec50 100644 (file)
--- a/lisp/diff.el
+++ b/lisp/diff.el
@@ -160,6 +160,21 @@ is nil, REGEXP matches only half a section.")
     (message "Parsing differences...done"))
   (setq compilation-error-list (nreverse compilation-error-list)))
 
+(defun diff-process-setup ()
+  "Set up \`compilation-exit-message-function' for \`diff'."
+  ;; Avoid frightening people with "abnormally terminated"
+  ;; if diff finds differences.
+  (set (make-local-variable 'compilation-exit-message-function)
+       (lambda (status code msg)
+        (cond ((not (eq status 'exit))
+               (cons msg code))
+              ((zerop code)
+               '("finished (no differences)\n" . "no differences"))
+              ((= code 1)
+               '("finished\n" . "differences found"))
+              (t
+               (cons msg code))))))
+
 ;;;###autoload
 (defun diff (old new &optional switches)
   "Find and display the differences between OLD and NEW files.
@@ -198,7 +213,8 @@ With prefix arg, prompt for diff switches."
        (new-alt (file-local-copy new))
        buf)
     (save-excursion
-       (let ((command
+       (let ((compilation-process-setup-function 'diff-process-setup)
+             (command
               (mapconcat 'identity
                          (append (list diff-command)
                                  ;; Use explicitly specified switches
@@ -221,18 +237,6 @@ With prefix arg, prompt for diff switches."
                                  "No more differences" "Diff"
                                  'diff-parse-differences))
          (set-buffer buf)
-         ;; Avoid frightening people with "abnormally terminated"
-         ;; if diff finds differences.
-         (set (make-local-variable 'compilation-exit-message-function)
-              (lambda (status code msg)
-                (cond ((not (eq status 'exit))
-                       (cons msg code))
-                      ((zerop code)
-                       '("finished (no differences)\n" . "no differences"))
-                      ((= code 1)
-                       '("finished\n" . "differences found"))
-                      (t
-                       (cons msg code)))))
          (set (make-local-variable 'diff-old-file) old)
          (set (make-local-variable 'diff-new-file) new)
          (set (make-local-variable 'diff-old-temp-file) old-alt)
@@ -243,6 +247,10 @@ With prefix arg, prompt for diff switches."
                               (delete-file diff-old-temp-file))
                           (if diff-new-temp-file
                               (delete-file diff-new-temp-file)))))
+         ;; When async processes aren't available, the compilation finish
+         ;; function doesn't get chance to run.  Invoke it by hand.
+         (or (fboundp 'start-process)
+             (funcall compilation-finish-function nil nil))
          buf))))
 
 ;;;###autoload