* lisp/minibuffer.el (completion-pcm--merge-completions): Make sure prefixes

and suffixes don't overlap.

Fixes: debbugs:14061

2 files changed, 18 insertions, 9 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 40b7cb011ae..fecad470900 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,12 +1,12 @@
 2013-03-27  Stefan Monnier  <monnier@iro.umontreal.ca>
 
+        * minibuffer.el (completion-pcm--merge-completions): Make sure prefixes
+        and suffixes don't overlap (bug#14061).
+
         * case-table.el: Use lexical-binding.
         (case-table-get-table): New function.
         (get-upcase-table): Use it.  Mark as obsolete.  Adjust callers.
 
-        * minibuffer.el (completion-pcm--merge-completions): Make sure prefixes
-        and suffixes don't overlap
-
 2013-03-27  Teodor Zlatanov  <tzz@lifelogs.com>
 
         * progmodes/subword.el: Add `superword-mode' to do word motion
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index ec237f0f664..016b16d0740 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -2997,12 +2997,21 @@ the same set of elements."
                 ;; here any more.
                 (unless unique
                   (push elem res)
-                  (when (memq elem '(star point prefix))
-                    ;; Extract common suffix additionally to common prefix.
-                    ;; Only do it for `point', `star', and `prefix' since for
-                    ;; `any' it could lead to a merged completion that
-                    ;; doesn't itself match the candidates.
-                    (let ((suffix (completion--common-suffix comps)))
+                  ;; Extract common suffix additionally to common prefix.
+                  ;; Don't do it for `any' since it could lead to a merged
+                  ;; completion that doesn't itself match the candidates.
+                  (when (and (memq elem '(star point prefix))
+                             ;; If prefix is one of the completions, there's no
+                             ;; suffix left to find.
+                             (not (assoc-string prefix comps t)))
+                    (let ((suffix
+                           (completion--common-suffix
+                            (if (zerop (length prefix)) comps
+                              ;; Ignore the chars in the common prefix, so we
+                              ;; don't merge '("abc" "abbc") as "ab*bc".
+                              (let ((skip (length prefix)))
+                                (mapcar (lambda (str) (substring str skip))
+                                        comps))))))
                       (cl-assert (stringp suffix))
                       (unless (equal suffix "")
                         (push suffix res)))))