core.whitespace: split trailing-space into blank-at-{eol,eof}

People who configured trailing-space depended on it to catch both extra
white space at the end of line, and extra blank lines at the end of file.
Earlier attempt to introduce only blank-at-eof gave them an escape hatch
to keep the old behaviour, but it is a regression until they explicitly
specify the new error class.

This introduces a blank-at-eol that only catches extra white space at the
end of line, and makes the traditional trailing-space a convenient synonym
to catch both blank-at-eol and blank-at-eof.  This way, people who used
trailing-space continue to catch both classes of errors.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 871384eb7..2a2f7fcdb 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -382,7 +382,7 @@ core.whitespace::
 	consider them as errors.  You can prefix `-` to disable
 	any of them (e.g. `-trailing-space`):
 +
-* `trailing-space` treats trailing whitespaces at the end of the line
+* `blank-at-eol` treats trailing whitespaces at the end of the line
   as an error (enabled by default).
 * `space-before-tab` treats a space character that appears immediately
   before a tab character in the initial indent part of the line as an
@@ -391,6 +391,8 @@ core.whitespace::
   space characters as an error (not enabled by default).
 * `blank-at-eof` treats blank lines added at the end of file as an error
   (enabled by default).
+* `trailing-space` is a short-hand to cover both `blank-at-eol` and
+  `blank-at-eof`.
 * `cr-at-eol` treats a carriage-return at the end of line as
   part of the line terminator, i.e. with it, `trailing-space`
   does not trigger if the character before such a carriage-return