Rudimentary support for vc-pull and vc-merge in Git and Mercurial.

* lisp/vc/vc.el (vc-pull): Make vc-update an alias for this, instead of
the other way around.

* lisp/vc/vc-git.el (vc-git-branches, vc-git-pull)
(vc-git-merge-branch): New functions.
(vc-git-history): New var.

* lisp/vc/vc-hg.el (vc-hg-history): New var.
(vc-hg-pull): Perform default pull if called via Lisp by vc-pull.
(vc-hg-merge-branch): New function.

1 files changed, 51 insertions, 0 deletions

diff --git a/lisp/vc/vc-git.el b/lisp/vc/vc-git.el
index c3ffa1fcf46..592fc77e2e3 100644
--- a/lisp/vc/vc-git.el
+++ b/lisp/vc/vc-git.el
@@ -122,6 +122,9 @@ If nil, use the value of `vc-diff-switches'.  If t, use no switches."
 (defvar vc-git-commits-coding-system 'utf-8
   "Default coding system for git commits.")
 
+;; History of Git commands.
+(defvar vc-git-history nil)
+
 ;;; BACKEND PROPERTIES
 
 (defun vc-git-revision-granularity () 'repository)
@@ -526,6 +529,21 @@ or an empty string if none."
 		    'help-echo stash-help-echo
 		    'face 'font-lock-variable-name-face))))))
 
+(defun vc-git-branches ()
+  "Return the existing branches, as a list of strings.
+The car of the list is the current branch."
+  (with-temp-buffer
+    (call-process "git" nil t nil "branch")
+    (goto-char (point-min))
+    (let (current-branch branches)
+      (while (not (eobp))
+	(when (looking-at "^\\([ *]\\) \\(.+\\)$")
+	  (if (string-equal (match-string 1) "*")
+	      (setq current-branch (match-string 2))
+	    (push (match-string 2) branches)))
+	(forward-line 1))
+      (cons current-branch (nreverse branches)))))
+
 ;;; STATE-CHANGING FUNCTIONS
 
 (defun vc-git-create-repo ()
@@ -587,6 +605,39 @@ or an empty string if none."
     (vc-git-command nil 0 file "reset" "-q" "--")
     (vc-git-command nil nil file "checkout" "-q" "--")))
 
+(defun vc-git-pull (prompt)
+  "Pull changes into the current Git branch.
+Normally, this runs \"git pull\".If there is no default
+location from which to pull or update, or if PROMPT is non-nil,
+prompt for the Git command to run."
+  (let* ((root (vc-git-root default-directory))
+	 (buffer (format "*vc-git : %s*" (expand-file-name root)))
+	 (command "pull")
+	 (git-program "git")
+	 args)
+    ;; If necessary, prompt for the exact command.
+    (when prompt
+      (setq args (split-string
+		  (read-shell-command "Run Git (like this): "
+				      "git pull"
+				      'vc-git-history)
+		  " " t))
+      (setq git-program (car  args)
+	    command     (cadr args)
+	    args        (cddr args)))
+    (apply 'vc-do-async-command buffer root git-program command args)))
+
+(defun vc-git-merge-branch ()
+  "Merge changes into the current Git branch.
+This prompts for a branch to merge from."
+  (let* ((root (vc-git-root default-directory))
+	 (buffer (format "*vc-git : %s*" (expand-file-name root)))
+	 (branches (cdr (vc-git-branches)))
+	 (merge-source
+	  (completing-read "Merge from branch: " branches nil t)))
+    (apply 'vc-do-async-command buffer root "git" "merge"
+	   (list merge-source))))
+
 ;;; HISTORY FUNCTIONS
 
 (defun vc-git-print-log (files buffer &optional shortlog start-revision limit)