[PATCH] maint.mk: detect_empty_lines_at_EOF_: avoid FP for an empty file

[Jim Meyering]

FYI,
I discovered (not in coreutils) that an empty version-controlled
file would provoke a false-positive match from this new rule.
But only when it is not the last file in the list.

  $ :>empty; echo > f; echo g > g; tail -n1 empty f g
  ==> empty <==

  ==> f <==


  ==> g <==
  g

This fixes it:

>From 2237d05df83cb4fc2adffaca11e0de3c2c5f28b1 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Sun, 11 Apr 2010 10:37:31 +0200
Subject: [PATCH] maint.mk: detect_empty_lines_at_EOF_: avoid FP for an empty 
file

* top/maint.mk (detect_empty_lines_at_EOF_): Don't confuse an
empty file with one that ends in an empty line.
---
 ChangeLog    |    6 ++++++
 top/maint.mk |    2 +-
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d79dcbf..1fdfa06 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-04-11  Jim Meyering  <address@hidden>
+
+       maint.mk: detect_empty_lines_at_EOF_: avoid FP for an empty file
+       * top/maint.mk (detect_empty_lines_at_EOF_): Don't confuse an
+       empty file with one that ends in an empty line.
+
 2010-04-10  Bruno Haible  <address@hidden>

        mkdir: Make it work on mingw64.
diff --git a/top/maint.mk b/top/maint.mk
index 6bfb4c1..b71304d 100644
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -674,7 +674,7 @@ sc_prohibit_cvs_keyword:
 #   perl -pi -0777 -e 's/\n\n+$/\n/' files...
 #
 detect_empty_lines_at_EOF_ =                                           \
-  /^==> ([^\n]+) <==\n\n/m and (print "$$1\n"), $$fail = 1;            \
+  /^==> ([^\n]+) <==\n\n\n/m and (print "$$1\n"), $$fail = 1;          \
   END { exit defined $$fail }
 sc_prohibit_empty_lines_at_EOF:
        @tail -n1 $$($(VC_LIST_EXCEPT)) /dev/null                       \
--
1.7.1.rc0.264.g94f6e