(dabbrev--substitute-expansion):

Convert all whitespace to single spaces,
except when it's carried over from the existing text.

1 files changed, 7 insertions, 3 deletions

diff --git a/lisp/dabbrev.el b/lisp/dabbrev.el
index 9dba5d61ebe..fd8b596d530 100644
--- a/lisp/dabbrev.el
+++ b/lisp/dabbrev.el
@@ -926,10 +926,14 @@ to record whether we upcased the expansion, downcased it, or did neither."
                     (cond ((equal abbrev (upcase abbrev)) 'upcase)
                           ((equal abbrev (downcase abbrev)) 'downcase)))))
 
-    ;; Convert newlines to spaces.
+    ;; Convert whitespace to single spaces.
     (if dabbrev--eliminate-newlines
-        (while (string-match "\n" expansion)
-          (setq expansion (replace-match " " nil nil expansion))))
+        ;; Start searching at end of ABBREV so that any whitespace
+        ;; carried over from the existing text is not changed.
+        (let ((pos (length abbrev)))
+          (while (string-match "[\n \t]+" expansion pos)
+            (setq pos (1+ (match-beginning 0)))
+            (setq expansion (replace-match " " nil nil expansion)))))
 
     (if old
         (save-excursion