Fix read-buffer by using minibuffer-completion-table

Try to use minibuffer-completion-table if it is bound otherwise fallback to
internal-complete-buffer.

The problem is that the definition of read-buffer-to-switch is wrong, as it
pass minibuffer-completion-table only through minibuffer-setup-hook which is
too late for helm and other backends used as read-buffer-function, so advise
read-buffer-to-switch from helm-mode.

1 files changed, 16 insertions, 9 deletions

diff --git a/helm-mode.el b/helm-mode.el
index 92a3570b..bb9a1f8b 100644
--- a/helm-mode.el
+++ b/helm-mode.el
@@ -513,7 +513,10 @@ If COLLECTION is an `obarray', a TEST should be needed. See `obarray'."
                                 ;; Don't convert
                                 ;; nil to "nil" (i.e the string)
                                 ;; it will be delq'ed on top.
-                                collect (if (null d) d (helm-stringify d)))
+                                for str = (if (null d) d (helm-stringify d))
+                                when (member str cands)
+                                do (setq cands (delete d cands))
+                                when str collect str)
                        cands))
               (t cands))))
 
@@ -1048,16 +1051,18 @@ This handler uses dynamic matching which allows honouring `completion-styles'."
            init hist default inherit-input-method
            name buffer standard)))
 
+(defun helm-read-buffer-to-switch (prompt)
+  (let ((minibuffer-completion-table (internal-complete-buffer-except)))
+    (read-buffer prompt (other-buffer (current-buffer))
+                 (confirm-nonexistent-file-or-buffer))))
+
 (defun helm--generic-read-buffer (prompt &optional default require-match predicate)
   "The `read-buffer-function' for `helm-mode'.
 Affects `switch-to-buffer' `kill-buffer' and related."
-  ;; Use `internal-complete-buffer-except' as default collection,
-  ;; assuming `switch-to-buffer' doesn't need the current buffer and
-  ;; `kill-buffer' add it on top of completion list.  This may be
-  ;; wrong in other functions, but lets use this as there is no better
-  ;; solutions to abstract this for now.
   (helm--completing-read-default
-   prompt (internal-complete-buffer-except) predicate require-match nil nil default))
+   prompt (or minibuffer-completion-table
+              (internal-complete-buffer "" nil t))
+   predicate require-match nil nil default))
 
 (cl-defun helm--completing-read-default
     (prompt collection &optional
@@ -2015,7 +2020,8 @@ Note: This mode is incompatible with Emacs23."
           ;; `ffap-read-file-or-url-internal' have been removed in
           ;; emacs-27 and `ffap-read-file-or-url' is fixed, so no need
           ;; to advice it.
-          (advice-add 'ffap-read-file-or-url :override #'helm-advice--ffap-read-file-or-url)))
+          (advice-add 'ffap-read-file-or-url :override #'helm-advice--ffap-read-file-or-url))
+        (advice-add 'read-buffer-to-switch :override #'helm-read-buffer-to-switch))
     (progn
       (remove-function completing-read-function #'helm--completing-read-default)
       (remove-function read-file-name-function #'helm--generic-read-file-name)
@@ -2023,7 +2029,8 @@ Note: This mode is incompatible with Emacs23."
       (remove-function completion-in-region-function #'helm--completion-in-region)
       (remove-hook 'ido-everywhere-hook #'helm-mode--ido-everywhere-hook)
       (when (fboundp 'ffap-read-file-or-url-internal)
-        (advice-remove 'ffap-read-file-or-url #'helm-advice--ffap-read-file-or-url)))))
+        (advice-remove 'ffap-read-file-or-url #'helm-advice--ffap-read-file-or-url))
+      (advice-remove 'read-buffer-to-switch #'helm-read-buffer-to-switch))))
 
 (provide 'helm-mode)