Generalize the file-name specific workaround in minibuffer-completion-help

* lisp/minibuffer.el (completion-base-suffix):
New function (bug#48356).
(minibuffer-completion-help): Use it here.
(minibuffer-completion-help): Cut off the double completion
boundary when it occurs inside
completion-list-insert-choice-function..

(cherry picked from commit 0288bc6c949e82f72790a60d067da31428ca433a)

diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 0f484a3f8cc5749a29ae4fefd2432e92d17d2e45..a3c1056af36817e854bdde3684c7760f36d09952 100644 (file)
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -92,6 +92,18 @@ the closest directory separators."
     (cons (or (cadr boundaries) 0)
           (or (cddr boundaries) (length suffix)))))
 
+(defun completion-base-suffix (start end table predicate)
+  "Return the completion boundary suffix as substring.
+START and END are the beginning and end of the entity being completed.
+TABLE and PREDICATE are completion table and predicate."
+  (let ((suffix (buffer-substring (point) end)))
+    (substring
+     suffix
+     (cdr (completion-boundaries (buffer-substring start (point))
+                                 table
+                                 predicate
+                                 suffix)))))
+
 (defun completion-metadata (string table pred)
   "Return the metadata of elements to complete at the end of STRING.
 This metadata is an alist.  Currently understood keys are:
@@ -2994,16 +3006,9 @@ completions list."
              (full-base (substring string 0 base-size))
              (base-prefix (buffer-substring (minibuffer--completion-prompt-end)
                                             (+ start base-size)))
-             (base-suffix
-              (if (or (eq (alist-get 'category (cdr md)) 'file)
-                      completion-in-region-mode-predicate)
-                  (buffer-substring
-                   (save-excursion
-                     (if completion-in-region-mode-predicate
-                         (point)
-                       (or (search-forward "/" nil t) (point-max))))
-                   (point-max))
-                ""))
+             (base-suffix (completion-base-suffix start end
+                                                  minibuffer-completion-table
+                                                  minibuffer-completion-predicate))
              (style completion--matching-style)
              (exceptional-candidates
               (or (not completions-exclude-exceptional-candidates)
@@ -3135,7 +3140,11 @@ completions list."
                            (delete-minibuffer-contents)
                            (insert start choice)
                            ;; Keep point after completion before suffix
-                           (save-excursion (insert end)))
+                           (save-excursion (insert
+                                            (completion--merge-suffix
+                                             choice
+                                             (1- (length choice))
+                                             end))))
                        (unless (or (zerop (length prefix))
                                    (equal prefix
                                           (buffer-substring-no-properties