Rewrite and rename diff-delete-trailing-whitespace.

* lisp/vc/diff-mode.el (diff-delete-trailing-whitespace): Rewrite, and
rename from diff-remove-trailing-whitespace (Bug#12831).

* files.texi (Diff Mode): Doc fixes for
diff-delete-trailing-whitespace.

2 files changed, 18 insertions, 12 deletions

diff --git a/doc/emacs/ChangeLog b/doc/emacs/ChangeLog
index 14ed58fb5c1..2a58735535f 100644
--- a/doc/emacs/ChangeLog
+++ b/doc/emacs/ChangeLog
@@ -1,5 +1,8 @@
 2012-11-08  Chong Yidong  <cyd@gnu.org>
 
+        * files.texi (Diff Mode): Doc fixes for
+        diff-delete-trailing-whitespace (Bug#12831).
+
         * trouble.texi (Crashing): Copyedits.
 
 2012-11-08  Glenn Morris  <rgm@gnu.org>
diff --git a/doc/emacs/files.texi b/doc/emacs/files.texi
index e2a85c6d138..8b609891caf 100644
--- a/doc/emacs/files.texi
+++ b/doc/emacs/files.texi
@@ -1341,7 +1341,7 @@ contents of the hunk.
   You can edit a Diff mode buffer like any other buffer.  (If it is
 read-only, you need to make it writable first.  @xref{Misc Buffer}.)
 Whenever you change a hunk, Diff mode attempts to automatically
-correct the line numbers in the hunk headers, to ensure that the diff
+correct the line numbers in the hunk headers, to ensure that the patch
 remains ``correct''.  To disable automatic line number correction,
 change the variable @code{diff-update-on-the-fly} to @code{nil}.
 
@@ -1472,17 +1472,20 @@ functions that are deleted by the patch.
 
 @c Trailing whitespace is NOT shown by default.
 @c Emacs's dir-locals file enables this (for some reason).
-@cindex trailing whitespace, in diffs
-@findex diff-remove-trailing-whitespace
-  Diff mode has various features for dealing with trailing whitespace
-on modified lines, since this is often an unintentional and unwanted
-change.  If you enable Whitespace mode in a Diff buffer, trailing
-whitespace is highlighted (@pxref{Useless Whitespace}).  The command
-@kbd{M-x diff-remove-trailing-whitespace} searches for trailing
-whitespace in the lines modified or added by a diff.  If it finds any,
-it tries to visit the associated file(s) and remove it.  It does not
-save the modifications, rather it lists any buffers that were modified
-so you can decide for yourself what to do.
+@cindex trailing whitespace, in patches
+@findex diff-delete-trailing-whitespace
+  Patches sometimes include trailing whitespace on modified lines, as
+an unintentional and undesired change.  There are two ways to deal
+with this problem.  Firstly, if you enable Whitespace mode in a Diff
+buffer (@pxref{Useless Whitespace}), it automatically highlights
+trailing whitespace in modified lines.  Secondly, you can use the
+command @kbd{M-x diff-delete-trailing-whitespace}, which searches for
+trailing whitespace in the lines modified by the patch, and removes
+that whitespace in both the patch and the patched source file(s).
+This command does not save the modifications that it makes, so you can
+decide whether to save the changes (the list of modified files is
+displayed in the echo area).  With a prefix argument, it tries to
+modify the original source files rather than the patched source files.
 
 @node Misc File Ops
 @section Miscellaneous File Operations