Separate input histories for 'C-x v !' and Git pulling & pushing

* lisp/vc/vc-dispatcher.el (vc-user-edit-command-history): Use
this as a dynamically bound variable, not a minibuffer history.
(vc-user-edit-command): Pass its value to read-shell-command.
* lisp/vc/vc-git.el (vc-git--pushpull):
* lisp/vc/vc.el (vc-edit-next-command): Bind it.
(vc-edit-next-command-history): New variable.
* etc/NEWS: Document the change.

etc/NEWS

@@ -2887,8 +2887,10 @@ To enable it again, use 'M-x enable-command'.
 
 ---
 *** 'C-x v !' has its own input history.
-This is shared with the input history of 'C-x v P' for certain backends
-which use the same mechanism as 'C-x v !'.
+
+---
+*** 'C-u C-x v +' and 'C-u C-x v P' for Git have an input history.
+This was already in place for Mercurial.
 
 ** Package
 

lisp/vc/vc-dispatcher.el

@@ -385,7 +385,7 @@ the man pages for \"torsocks\" for more details about Tor."
   :group 'vc)
 
 (defvar vc-user-edit-command-history nil
-  "Minibuffer history for `vc-user-edit-command'.")
+  "Name of minibuffer history variable for `vc-user-edit-command'.")
 
 (defun vc-user-edit-command (command file-or-list flags)
   "Prompt the user to edit VC command COMMAND and FLAGS.
@@ -402,7 +402,7 @@ Intended to be used as the value of `vc-filter-command-function'."
                                                         (butlast flags)
                                                       flags))))
                            " ")
-                   'vc-user-edit-command-history))))
+                   vc-user-edit-command-history))))
     (list (car edited) file-or-list
           (nconc (cdr edited) (and files-separator-p '("--"))))))
 

lisp/vc/vc-git.el

@@ -1614,7 +1614,9 @@ If PROMPT is non-nil, prompt for the Git command to run."
          (vc-filter-command-function
           (if prompt
               (lambda (&rest args)
-                (cl-destructuring-bind (&whole args git _ flags)
+                (cl-destructuring-bind
+                    (&whole args git _ flags
+                            &aux (vc-user-edit-command-history 'vc-git-history))
                     (apply #'vc-user-edit-command args)
                   (setq git-program git
                         command (car flags)

lisp/vc/vc.el

@@ -5026,6 +5026,9 @@ log entries should be gathered."
 
 (defvar vc-filter-command-function)
 
+(defvar vc-edit-next-command-history nil
+  "Minibuffer history for `vc-edit-next-command'.")
+
 ;;;###autoload
 (defun vc-edit-next-command ()
   "Request editing the next VC shell command before execution.
@@ -5049,7 +5052,8 @@ immediately after this one."
     (add-hook 'prefix-command-echo-keystrokes-functions echofun)
     (setq vc-filter-command-function
           (lambda (&rest args)
-            (apply #'vc-user-edit-command (apply old args))))))
+            (let ((vc-user-edit-command-history 'vc-edit-next-command-history))
+              (apply #'vc-user-edit-command (apply old args)))))))
 
 ;; This is used in .dir-locals.el in the Emacs source tree.
 ;;;###autoload (put 'vc-prepare-patches-separately 'safe-local-variable 'booleanp)