bug#19548: VC changes under-documented, needlessly incompatible

[Dmitry Gutov <dgutov@yandex.ru>]

On 05/23/2016 08:37 PM, Eli Zaretskii wrote:

> I'm not sure I see the gain, given that (AFAIU) CVS is the only
> back-end for which this option is relevant.

For the benefit of someone who customized vc-stay-local 10 years ago? 
Not very compelling, I agree.

Does this patch have your blessing?

Someone should test it out, to be safe; the only CVS repo I have to 
experiment on doesn't seem to work great with either version of the code 
(but then, it's an old public checkout of the Samba repository).

diff --git a/lisp/vc/vc-cvs.el b/lisp/vc/vc-cvs.el
index 2dca708..a2499a2 100644
--- a/lisp/vc/vc-cvs.el
+++ b/lisp/vc/vc-cvs.el
@@ -121,7 +121,7 @@ vc-cvs-use-edit
    :version "21.1"
    :group 'vc-cvs)

-(defcustom vc-stay-local 'only-file
+(defcustom vc-cvs-stay-local 'only-file
    "Non-nil means use local operations when possible for remote 
repositories.
  This avoids slow queries over the network and instead uses heuristics
  and past information to determine the current status of a file.
@@ -131,11 +131,11 @@ vc-stay-local
  all other VC operations.

  The value can also be a regular expression or list of regular
-expressions to match against the host name of a repository; then VC
-only stays local for hosts that match it.  Alternatively, the value
-can be a list of regular expressions where the first element is the
-symbol `except'; then VC always stays local except for hosts matched
-by these regular expressions."
+expressions to match against the host name of a repository; then
+vc-cvs only stays local for hosts that match it.  Alternatively,
+the value can be a list of regular expressions where the first
+element is the symbol `except'; then vc-cvs always stays local
+except for hosts matched by these regular expressions."
    :type '(choice (const :tag "Always stay local" t)
  		 (const :tag "Only for file operations" only-file)
  		 (const :tag "Don't stay local" nil)
@@ -789,8 +789,7 @@ vc-cvs-stay-local-p
  individually should stay local."
    (if (listp file)
        (delq nil (mapcar (lambda (arg) (vc-cvs-stay-local-p arg)) file))
-    (let* ((sym (vc-make-backend-sym 'CVS 'stay-local))
-          (stay-local (if (boundp sym) (symbol-value sym) vc-stay-local)))
+    (let ((stay-local vc-cvs-stay-local))
        (if (symbolp stay-local) stay-local
         (let ((dirname (if (file-directory-p file)
                            (directory-file-name file)