(change-log-resolve-conflict): Don't lose data if the merge fails.

2 files changed, 31 insertions, 11 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index bf5b5da1be2..81e89689913 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2007-07-20  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * add-log.el (change-log-resolve-conflict): Don't lose data if the
+        merge fails.
+
 2007-07-20  Dan Nicolaescu  <dann@ics.uci.edu>
 
         * progmodes/compile.el (compilation-auto-jump-to-first-error):
diff --git a/lisp/add-log.el b/lisp/add-log.el
index 63212a75dc8..caea921d25f 100644
--- a/lisp/add-log.el
+++ b/lisp/add-log.el
@@ -1043,17 +1043,32 @@ Point is assumed to be at the start of the entry."
 
 (defun change-log-resolve-conflict ()
   "Function to be used in `smerge-resolve-function'."
-  (let ((buf (current-buffer)))
-    (with-temp-buffer
-      (insert-buffer-substring buf (match-beginning 1) (match-end 1))
-      (save-match-data (change-log-mode))
-      (let ((other-buf (current-buffer)))
-        (with-current-buffer buf
-          (save-excursion
-            (save-restriction
-              (narrow-to-region (match-beginning 0) (match-end 0))
-              (replace-match (match-string 3) t t)
-              (change-log-merge other-buf))))))))
+  (save-excursion
+    (save-restriction
+      (narrow-to-region (match-beginning 0) (match-end 0))
+      (let ((mb1 (match-beginning 1))
+            (me1 (match-end 1))
+            (mb3 (match-beginning 3))
+            (me3 (match-end 3))
+            (tmp1 (generate-new-buffer " *changelog-resolve-1*"))
+            (tmp2 (generate-new-buffer " *changelog-resolve-2*")))
+        (unwind-protect
+            (let ((buf (current-buffer)))
+              (with-current-buffer tmp1
+                (change-log-mode)
+                (insert-buffer-substring buf mb1 me1))
+              (with-current-buffer tmp2
+                (change-log-mode)
+                (insert-buffer-substring buf mb3 me3)
+                ;; Do the merge here instead of inside `buf' so as to be
+                ;; more robust in case change-log-merge fails.
+                (change-log-merge tmp1))
+              (goto-char (point-max))
+              (delete-region (point-min)
+                             (prog1 (point)
+                               (insert-buffer-substring tmp2))))
+          (kill-buffer tmp1)
+          (kill-buffer tmp2))))))
 
 ;;;###autoload
 (defun change-log-merge (other-log)