diff --whitespace=warn/error: obey blank-at-eof

The "diff --check" code used to conflate trailing-space whitespace error
class with this, but now we have a proper separate error class, we should
check it under blank-at-eof, not trailing-space.

The whitespace error is not about _having_ blank lines at end, but about
adding _new_ blank lines.  To keep the message consistent with what is
given by "git apply", call whitespace_error_string() to generate it,
instead of using a hardcoded custom message.

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

1 files changed, 7 insertions, 3 deletions

diff --git a/diff.c b/diff.c
index 1eddd59..a693d18 100644
--- a/diff.c
+++ b/diff.c
@@ -1650,10 +1650,14 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
 		ecb.priv = &data;
 		xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 
-		if ((data.ws_rule & WS_TRAILING_SPACE) &&
+		if ((data.ws_rule & WS_BLANK_AT_EOF) &&
 		    data.trailing_blanks_start) {
-			fprintf(o->file, "%s:%d: ends with blank lines.\n",
-				data.filename, data.trailing_blanks_start);
+			static char *err;
+
+			if (!err)
+				err = whitespace_error_string(WS_BLANK_AT_EOF);
+			fprintf(o->file, "%s:%d: %s\n",
+				data.filename, data.trailing_blanks_start, err);
 			data.status = 1; /* report errors */
 		}
 	}