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From: Junio C Hamano <gitster@pobox.com>
To: git@vger.kernel.org
Subject: [PATCH v2 2/4] apply: make update_pre_post_images() sanity check the given postlen
Date: Thu, 22 Jan 2015 14:58:23 -0800	[thread overview]
Message-ID: <1421967505-16879-3-git-send-email-gitster@pobox.com> (raw)
In-Reply-To: <1421967505-16879-1-git-send-email-gitster@pobox.com>

"git apply --whitespace=fix" used to be able to assume that fixing
errors will always reduce the size by e.g. stripping whitespaces at
the end of lines or collapsing runs of spaces into tabs at the
beginning of lines.  An update to accomodate fixes that lengthens
the result by e.g. expanding leading tabs into spaces were made long
time ago but the logic miscounted the necessary space after such
whitespace fixes, leading to either under-allocation or over-usage
of already allocated space.

Illustrate this with a runtime sanity-check to protect us from
future breakage.  The test was stolen from Kyle McKay who helped
to identify the problem.

Helped-by: "Kyle J. McKay" <mackyle@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/apply.c               |   6 +++
 t/t4138-apply-ws-expansion.sh | 121 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+)
 create mode 100755 t/t4138-apply-ws-expansion.sh

diff --git a/builtin/apply.c b/builtin/apply.c
index 31f8733..da6fb35 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -2171,6 +2171,12 @@ static void update_pre_post_images(struct image *preimage,
 		ctx++;
 	}
 
+	if (postlen
+	    ? postlen < new - postimage->buf
+	    : postimage->len < new - postimage->buf)
+		die("BUG: caller miscounted postlen: asked %d, orig = %d, used = %d",
+		    (int)postlen, (int) postimage->len, (int)(new - postimage->buf));
+
 	/* Fix the length of the whole thing */
 	postimage->len = new - postimage->buf;
 	postimage->nr -= reduced;
diff --git a/t/t4138-apply-ws-expansion.sh b/t/t4138-apply-ws-expansion.sh
new file mode 100755
index 0000000..0ffe33f
--- /dev/null
+++ b/t/t4138-apply-ws-expansion.sh
@@ -0,0 +1,121 @@
+#!/bin/sh
+#
+# Copyright (C) 2015 Kyle J. McKay
+#
+
+test_description='git apply test patches with whitespace expansion.'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	#
+	## create test-N, patchN.patch, expect-N files
+	#
+
+	# test 1
+	printf "\t%s\n" 1 2 3 4 5 6 >before &&
+	printf "\t%s\n" 1 2 3 >after &&
+	printf "%64s\n" a b c >>after &&
+	printf "\t%s\n" 4 5 6 >>after &&
+	git diff --no-index before after |
+		sed -e "s/before/test-1/" -e "s/after/test-1/" >patch1.patch &&
+	printf "%64s\n" 1 2 3 4 5 6 >test-1 &&
+	printf "%64s\n" 1 2 3 a b c 4 5 6 >expect-1 &&
+
+	# test 2
+	printf "\t%s\n" a b c d e f >before &&
+	printf "\t%s\n" a b c >after &&
+	n=10 &&
+	x=1 &&
+	while test $x -lt $n
+	do
+		printf "%63s%d\n" "" $x >>after
+		x=$(( $x + 1 ))
+	done &&
+	printf "\t%s\n" d e f >>after &&
+	git diff --no-index before after |
+		sed -e "s/before/test-2/" -e "s/after/test-2/" >patch2.patch &&
+	printf "%64s\n" a b c d e f >test-2 &&
+	printf "%64s\n" a b c >expect-2 &&
+	x=1 &&
+	while test $x -lt $n
+	do
+		printf "%63s%d\n" "" $x >>expect-2
+		x=$(( $x + 1 ))
+	done &&
+	printf "%64s\n" d e f >>expect-2 &&
+
+	# test 3
+	printf "\t%s\n" a b c d e f >before &&
+	printf "\t%s\n" a b c >after &&
+	n=100 &&
+	x=0 &&
+	while test $x -lt $n
+	do
+		printf "%63s%02d\n" "" $x >>after
+		x=$(( $x + 1 ))
+	done &&
+	printf "\t%s\n" d e f >>after &&
+	git diff --no-index before after |
+	sed -e "s/before/test-3/" -e "s/after/test-3/" >patch3.patch &&
+	printf "%64s\n" a b c d e f >test-3 &&
+	printf "%64s\n" a b c >expect-3 &&
+	x=0 &&
+	while test $x -lt $n
+	do
+		printf "%63s%02d\n" "" $x >>expect-3
+		x=$(( $x + 1 ))
+	done &&
+	printf "%64s\n" d e f >>expect-3 &&
+
+	# test 4
+	>before &&
+	x=0 &&
+	while test $x -lt 50
+	do
+		printf "\t%02d\n" $x >>before
+		x=$(( $x + 1 ))
+	done &&
+	cat before >after &&
+	printf "%64s\n" a b c >>after &&
+	while test $x -lt 100
+	do
+		printf "\t%02d\n" $x >>before
+		printf "\t%02d\n" $x >>after
+		x=$(( $x + 1 ))
+	done &&
+	git diff --no-index before after |
+	sed -e "s/before/test-4/" -e "s/after/test-4/" >patch4.patch &&
+	>test-4 &&
+	x=0 &&
+	while test $x -lt 50
+	do
+		printf "%63s%02d\n" "" $x >>test-4
+		x=$(( $x + 1 ))
+	done &&
+	cat test-4 >expect-4 &&
+	printf "%64s\n" a b c >>expect-4 &&
+	while test $x -lt 100
+	do
+		printf "%63s%02d\n" "" $x >>test-4
+		printf "%63s%02d\n" "" $x >>expect-4
+		x=$(( $x + 1 ))
+	done &&
+
+	git config core.whitespace tab-in-indent,tabwidth=63 &&
+	git config apply.whitespace fix
+
+'
+
+# Note that `patch` can successfully apply all patches when run
+# with the --ignore-whitespace option.
+
+for t in 1 2 3 4
+do
+	test_expect_success 'apply with ws expansion (t=$t)' '
+		git apply patch$t.patch &&
+		test_cmp test-$t expect-$t
+	'
+done
+
+test_done
-- 
2.3.0-rc1-116-g84c5016

  parent reply	other threads:[~2015-01-22 22:58 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-14 18:20 Segmentation fault in git apply Michael Blume
2015-01-14 18:40 ` Michael Blume
2015-01-14 18:44   ` Michael Blume
2015-01-14 18:48     ` Michael Blume
2015-01-14 18:58       ` Michael Blume
2015-01-14 19:09         ` Michael Blume
2015-01-15  8:26           ` Kyle J. McKay
2015-01-15  9:10             ` Kyle J. McKay
2015-01-16 19:58               ` Junio C Hamano
2015-01-16 23:54                 ` [PATCH] apply: count the size of postimage correctly Junio C Hamano
2015-01-18 10:49                   ` [PATCH] test: add git apply whitespace expansion tests Kyle J. McKay
2015-01-18 22:11                     ` Junio C Hamano
2015-01-19  3:54                       ` Kyle J. McKay
2015-01-21 22:33                         ` Junio C Hamano
2015-01-22  6:55                           ` Kyle J. McKay
2015-01-22 19:23                             ` Junio C Hamano
2015-01-23  0:12                               ` Kyle J. McKay
2015-01-22 22:58                           ` [PATCH v2 0/4] apply --whitespace=fix buffer corruption fix Junio C Hamano
2015-01-22 22:58                             ` [PATCH v2 1/4] apply.c: typofix Junio C Hamano
2015-01-22 23:17                               ` Stefan Beller
2015-01-22 23:42                                 ` Junio C Hamano
2015-01-22 23:48                                   ` Stefan Beller
2015-01-22 22:58                             ` Junio C Hamano [this message]
2015-01-22 22:58                             ` [PATCH v2 3/4] apply: count the size of postimage correctly Junio C Hamano
2015-01-22 22:58                             ` [PATCH v2 4/4] apply: detect and mark whitespace errors in context lines when fixing Junio C Hamano
2015-01-14 18:50 ` Segmentation fault in git apply Junio C Hamano

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