Fix some mpc.el updating quirks

* lisp/mpc.el (mpc-songs-jump-to): Update the status buffer.

* lisp/mpc.el (mpc-stop): M-x mpc-stop clears playlist queue. So
updating *MPC-Songs* buffer is useful.

* lisp/mpc.el (mpc-cmd-delete): I noticed M-x mpc-playlist-delete
always messages “Deleted 1 songs” even if playlist queue has more
than one songs.  This is because mpc-cmd-delete’s sort modifies
songs-poss by side effect.  Using copy-sequence fixes this (bug#44093).
* lisp/mpc.el (mpc-cmd-move): Ditto.

1 files changed, 6 insertions, 5 deletions

diff --git a/lisp/mpc.el b/lisp/mpc.el
index d22b7ab4506..fade23e3cc2 100644
--- a/lisp/mpc.el
+++ b/lisp/mpc.el
@@ -819,8 +819,8 @@ The songs are returned as alists."
 (defun mpc-cmd-status ()
   (mpc-proc-cmd-to-alist "status"))
 
-(defun mpc-cmd-play ()
-  (mpc-proc-cmd "play")
+(defun mpc-cmd-play (&optional sn)
+  (mpc-proc-cmd (if sn (list "play" sn) "play"))
   (mpc-status-refresh))
 
 (defun mpc-cmd-seekcur (time)
@@ -849,7 +849,7 @@ If PLAYLIST is t or nil or missing, use the main playlist."
                          ;; Sort them from last to first, so the renumbering
                          ;; caused by the earlier deletions don't affect
                          ;; later ones.
-                         (sort song-poss '>))))
+                         (sort (copy-sequence song-poss) '>))))
     (if (stringp playlist)
         (puthash (cons 'Playlist playlist) nil mpc--find-memoize)))
 
@@ -873,7 +873,7 @@ If PLAYLIST is t or nil or missing, use the main playlist."
               ;; Sort them from last to first, so the renumbering
               ;; caused by the earlier deletions affect
               ;; later ones a bit less.
-              (sort song-poss '>))))
+              (sort (copy-sequence song-poss) '>))))
     (if (stringp playlist)
         (puthash (cons 'Playlist playlist) nil mpc--find-memoize))))
 
@@ -2089,7 +2089,7 @@ This is used so that they can be compared with `eq', which is needed for
      ((null (with-current-buffer plbuf (re-search-forward re nil t)))
       ;; song-file only appears once in the playlist: no ambiguity,
       ;; we're good to go!
-      (mpc-proc-cmd (list "play" sn)))
+      (mpc-cmd-play sn))
      (t
       ;; The song appears multiple times in the playlist.  If the current
       ;; buffer holds not only the destination song but also the current
@@ -2391,6 +2391,7 @@ This is used so that they can be compared with `eq', which is needed for
   (interactive)
   (mpc-cmd-stop)
   (mpc-cmd-clear)
+  (mpc-songs-refresh)
   (mpc-status-refresh))
 
 (defun mpc-pause ()