From: Sean Whitton <spwhitton@spwhitton.name>
Date: Sun, 29 Jun 2025 13:53:37 +0000 (+0100)
Subject: VC: Fix several START-REVISION versus LIMIT issues
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=86235ca52250c059688aff1453b99fd16927f0fc;p=emacs.git

VC: Fix several START-REVISION versus LIMIT issues

* lisp/vc/vc-git.el (vc-git-print-log): When LIMIT and
START-REVISION are both supplied, use START-REVISION as the
newest commit, and LIMIT as a base (problem was introduced in
the commit adding 'vc-diff-mergebase' and 'vc-log-mergebase').
* lisp/vc/vc.el (vc-default-log-incoming)
(vc-default-log-outgoing): Fix order of START-REVISION and LIMIT
arguments passed to 'print-log' backend function.
(vc-log-mergebase): Fix order of START-REVISION and LIMIT
arguments passed to 'vc-print-log-internal'.

(cherry picked from commit d23b605f754d07a9abf298353d7d17197094477b)
---

diff --git a/lisp/vc/vc-git.el b/lisp/vc/vc-git.el
index 9ab82f7f5ac..89aa98fec8b 100644
--- a/lisp/vc/vc-git.el
+++ b/lisp/vc/vc-git.el
@@ -1560,7 +1560,7 @@ If SHORTLOG is non-nil, use a short format based on `vc-git-root-log-format'.
 \(This requires at least Git version 1.5.6, for the --graph option.)
 If START-REVISION is non-nil, it is the newest revision to show.
 If LIMIT is a number, show no more than this many entries.
-If LIMIT is a revision string, use it as an end-revision."
+If LIMIT is a non-empty string, use it as a base."
   (let ((coding-system-for-read
          (or coding-system-for-read vc-git-log-output-coding-system)))
     ;; `vc-do-command' creates the buffer, but we need it before running
@@ -1568,7 +1568,19 @@ If LIMIT is a revision string, use it as an end-revision."
     (vc-setup-buffer buffer)
     ;; If the buffer exists from a previous invocation it might be
     ;; read-only.
-    (let ((inhibit-read-only t))
+    (let ((inhibit-read-only t)
+          ;; In some parts of Git's revision and revision range
+          ;; notation, an empty string is equivalent to "HEAD", but not
+          ;; everywhere.  For simplicity we'll always be explicit.
+          (start-revision (if (member start-revision '(nil ""))
+                              "HEAD"
+                            start-revision))
+          ;; An empty string LIMIT doesn't make sense given the
+          ;; specification of this VC backend function, and is tricky to
+          ;; deal with in combination with Git's double-dot notation for
+          ;; specifying revision ranges.  So discard it right away.
+          (limit (and (not (equal limit ""))
+                      limit)))
       (with-current-buffer buffer
 	(apply #'vc-git-command buffer
 	       'async files
@@ -1591,14 +1603,11 @@ If LIMIT is a revision string, use it as an end-revision."
                  (if shortlog vc-git-shortlog-switches vc-git-log-switches))
                 (when (numberp limit)
                   (list "-n" (format "%s" limit)))
-		(when start-revision
-                  (if (and limit (not (numberp limit)))
-                      (list (concat start-revision ".." (if (equal limit "")
-                                                            "HEAD"
-                                                          limit)))
-                    (list start-revision)))
                 (when (eq vc-log-view-type 'with-diff)
                   (list "-p"))
+                (list (concat (and (stringp limit)
+                                   (concat limit ".."))
+                              start-revision))
 		'("--")))))))
 
 (defun vc-git-incoming-revision (remote-location)
diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index b06f3f9103d..868f8e5d775 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -347,7 +347,8 @@
 ;;   Insert the revision log for FILES into BUFFER.
 ;;   If SHORTLOG is non-nil insert a short version of the log.
 ;;   If LIMIT is non-nil insert only insert LIMIT log entries.
-;;   When LIMIT is a string it means stop at that revision.
+;;   When LIMIT is a string it means stop right before that revision
+;;   (i.e., revision LIMIT itself should not be included in the log).
 ;;   If the backend does not support limiting the number of entries to
 ;;   show it should return `limit-unsupported'.
 ;;   If START-REVISION is given, then show the log starting from that
@@ -3305,8 +3306,8 @@ In some version control systems REMOTE-LOCATION can be a remote branch name."
                                          remote-location)
                         (user-error "No incoming revision -- local-only branch?"))))
       (vc-call-backend backend 'print-log (list rootdir) buffer t
-                       (vc-call-backend backend 'mergebase incoming)
-                       incoming))))
+                       incoming
+                       (vc-call-backend backend 'mergebase incoming)))))
 
 ;;;###autoload
 (defun vc-log-outgoing (&optional remote-location)
@@ -3327,8 +3328,8 @@ In some version control systems REMOTE-LOCATION can be a remote branch name."
                                          remote-location)
                         (user-error "No incoming revision -- local-only branch?"))))
       (vc-call-backend backend 'print-log (list rootdir) buffer t
-                       (vc-call-backend backend 'mergebase incoming)
-                       ""))))
+                       ""
+                       (vc-call-backend backend 'mergebase incoming)))))
 
 ;;;###autoload
 (defun vc-log-search (pattern)
@@ -3362,7 +3363,7 @@ The merge base is a common ancestor of revisions REV1 and REV2."
           (list backend (list (vc-call-backend backend 'root default-directory)))))))
   (vc--with-backend-in-rootdir "VC root-log"
     (setq rev1 (vc-call-backend backend 'mergebase rev1 rev2))
-    (vc-print-log-internal backend (list rootdir) rev1 t (or rev2 ""))))
+    (vc-print-log-internal backend (list rootdir) (or rev2 "") t rev1)))
 
 ;;;###autoload
 (defun vc-region-history (from to)