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Re: update-copyright copyright notice corruption bug


Joseph S. Myers wrote:
> On Wed, 2 Jan 2013, Eric Blake wrote:
>
>> The original was:
>>
>>    Copyright (C) 1995,97,99 Free Software Foundation, Inc.
>>
>> and that pattern (4-digits followed by 2-digits, with gaps in the years,
>> but no spaces in the listing) is not currently tested in the
>> update-copyright testsuite.
>
> I don't believe the "no spaces" is required for this bug to show.  The
> corruption also appeared for misc/sys/file.h, for example:
>
> -/* Copyright (C) 1991, 92, 96, 97, 98, 99 Free Software Foundation, Inc.
> +/* Copyright (C) 11999, 20131, 1992-1999 Free Software Foundation, Inc.

Here's a minimal test case:

  $ echo '/* Copyright 1991, 99 Free Software Foundation, Inc. */' > k.c
  $ build-aux/update-copyright k.c && cat k.c
  /* Copyright 11999, 20131, 1999 Free Software Foundation, Inc. */

It tickles a bug whereby an attempt to replace that "final" year number, 99,
with 1999 mistakenly matches the "99" in the middle of the *first* date, 1991:

Here's the fix:

>From 25b6e62a48c9991f8166c490463cf73ebc874db4 Mon Sep 17 00:00:00 2001
From: Jim Meyering <jim@meyering.net>
Date: Thu, 3 Jan 2013 10:23:30 +0100
Subject: [PATCH] update-copyright: avoid copyright notice date corruption

Given a sequence of copyright year numbers in which the final
one was a two-digit number that happened to be a substring of
a preceding four-digit year number, we would mistakenly update
the substring (from two- to four-digit) rather than the two-digit
number at the end, which, combined with the addition of the current
4-digit year number would yield two 5-digit year numbers, e.g.,
here, it would convert the first "99" to "1999, 2013" rather than
the final one:
  1991, 99
  11999, 20131, 1999
* build-aux/update-copyright: Tighten a regexp.
* tests/test-update-copyright.sh: Add a test case to trigger the bug.
Reported by Joseph Myers in
http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/32281
---
 ChangeLog                      | 18 ++++++++++++++++++
 build-aux/update-copyright     |  2 +-
 tests/test-update-copyright.sh |  6 ++++++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index db79efc..73c186d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+2013-01-03  Jim Meyering  <jim@meyering.net>
+
+	update-copyright: avoid copyright notice date corruption
+	Given a sequence of copyright year numbers in which the final
+	one was a two-digit number that happened to be a substring of
+	a preceding four-digit year number, we would mistakenly update
+	the substring (from two- to four-digit) rather than the two-digit
+	number at the end, which, combined with the addition of the current
+	4-digit year number would yield two 5-digit year numbers, e.g.,
+	here, it would convert the first "99" to "1999, 2013" rather than
+	the final one:
+	  1991, 99
+	  11999, 20131, 1999
+	* build-aux/update-copyright: Tighten a regexp.
+	* tests/test-update-copyright.sh: Add a test case to trigger the bug.
+	Reported by Joseph Myers in
+	http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/32281
+
 2013-01-01  Paul Eggert  <eggert@cs.ucla.edu>

 	regex: omit needless signed-pointer casts
diff --git a/build-aux/update-copyright b/build-aux/update-copyright
index c51ac64..da84c66 100755
--- a/build-aux/update-copyright
+++ b/build-aux/update-copyright
@@ -3,7 +3,7 @@ eval '(exit $?0)' && eval 'exec perl -wS -0777 -pi "$0" ${1+"$@"}'
     if 0;
 # Update an FSF copyright year list to include the current year.

-my $VERSION = '2012-02-05.21:39'; # UTC
+my $VERSION = '2013-01-03.08:43'; # UTC

 # Copyright (C) 2009-2013 Free Software Foundation, Inc.
 #
diff --git a/tests/test-update-copyright.sh b/tests/test-update-copyright.sh
index efecebe..60cb372 100755
--- a/tests/test-update-copyright.sh
+++ b/tests/test-update-copyright.sh
@@ -505,6 +505,9 @@ cat > $TMP.extra-text-space <<EOF
  /* Copyright 1987, 1988, 1991, 1992 Free Software Foundation, Inc. ***
     * End of comments. */
 EOF
+cat > $TMP.two-digit-final-is-substr-of-first <<EOF
+ /* Copyright 1991, 99 Free Software Foundation, Inc. */
+EOF
 UPDATE_COPYRIGHT_YEAR=2010 \
   update-copyright $TMP.* 1> $TMP-stdout 2> $TMP-stderr
 compare /dev/null $TMP-stdout || exit 1
@@ -536,6 +539,9 @@ compare - $TMP.extra-text-space <<EOF || exit 1
     Inc. ***
     * End of comments. */
 EOF
+compare - $TMP.two-digit-final-is-substr-of-first <<EOF || exit 1
+ /* Copyright 1991, 1999, 2010 Free Software Foundation, Inc. */
+EOF
 rm $TMP*

 exit 0
--
1.8.1


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