Clarify documentation of 'vc-responsible-backend' wrt symlinks

* lisp/vc/vc.el (vc-responsible-backend): Clarify that symlinks
are not resolved when the VC backend is reported.

* doc/lispref/files.texi (Truenames): Document
'vc-responsible-backend'.  (Bug#23436)
* doc/emacs/maintaining.texi (Version Control Systems): Fix a
typo.

2 files changed, 16 insertions, 1 deletions

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index aca29910b7d..0a47b4c3b76 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -223,7 +223,7 @@ basic editing operations under Bazaar.
 @cindex SRC
 @cindex src
 @item
-SRC (src) is RCS, reloaded - a specialized version-control system
+SRC (src) is RCS, reloaded---a specialized version-control system
 designed for single-file projects worked on by only one person.  It
 allows multiple files with independent version-control histories to
 exist in one directory, and is thus particularly well suited for
diff --git a/doc/lispref/files.texi b/doc/lispref/files.texi
index 6b7ee19d5f3..544992d4ba5 100644
--- a/doc/lispref/files.texi
+++ b/doc/lispref/files.texi
@@ -1138,6 +1138,21 @@ compares the truenames of the two directories.  If @var{dir} does not
 name an existing directory, the return value is @code{nil}.
 @end defun
 
+@defun vc-responsible-backend file
+This function determines the responsible VC backend of the given
+@var{file}.  For example, if @file{emacs.c} is a file tracked by Git,
+@w{@code{(vc-responsible-backend "emacs.c")}} returns @samp{Git}.
+Note that if @var{file} is a symbolic link,
+@code{vc-responsible-backend} will not resolve it---the backend of the
+symbolic link file itself is reported.  To get the backend VC of the
+file to which @var{file} refers, wrap @var{file} with a symbolic link
+resolving function such as @code{file-chase-links}:
+
+@smallexample
+(vc-responsible-backend (file-chase-links "emacs.c"))
+@end smallexample
+@end defun
+
 @node File Attributes
 @subsection File Attributes
 @cindex file attributes