[PATCH] rerere: demonstrate a weakness with identical conflicts in different files

[Johannes Sixt <j.sixt@viscovery.net>]

From: Johannes Sixt <j6t@kdbg.org>

When code sections are duplicated in different files and identical
conflicts arise simultaneously in these sections, then rerere resolves only
the first one and leaves the others unresolved.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
---
 I encounter this situation several times a year, and every now and then
 it is particularly annoying because the conflicts are extensive.

 I would appreciate if you could have a look whether this is fixed
 easily. I tried myself, but I can't find the point where the
 subsequent conflicts are ignored.

 -- Hannes

 t/t4208-rerere-dup.sh |   77 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 77 insertions(+), 0 deletions(-)
 create mode 100755 t/t4208-rerere-dup.sh

diff --git a/t/t4208-rerere-dup.sh b/t/t4208-rerere-dup.sh
new file mode 100755
index 0000000..34c182a
--- /dev/null
+++ b/t/t4208-rerere-dup.sh
@@ -0,0 +1,77 @@
+#!/bin/sh
+#
+# Copyright (c) 2010 Johannes Sixt
+#
+
+test_description='test git rerere when sections of files are duplicated,
+and identical conflicts arise in these sections simultaneously.
+'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	cat > a1 <<- EOF &&
+	alpha
+	beta
+	gamma
+	EOF
+	sed -e s/alpha/ALPHA/ <a1 >a2 &&
+
+	git add a1 a2 &&
+	git commit -q -a -m initial &&
+
+	git checkout -b first &&
+	cat > a1 <<- EOF &&
+	alpha
+	BETA
+	gamma
+	EOF
+	sed -e s/alpha/ALPHA/ <a1 >a2 &&
+	git commit -q -a -m first &&
+
+	git checkout master &&
+	cat > a1 <<- EOF &&
+	alpha
+	----
+	gamma
+	EOF
+	sed -e s/alpha/ALPHA/ <a1 >a2 &&
+	git commit -q -a -m master &&
+	git config rerere.enabled true
+'
+
+test_expect_success 'merge records only one conflict' '
+	test_must_fail git merge first &&
+	sha1=$(ls .git/rr-cache) &&
+	test $(echo $sha1 | wc -w) = 1
+'
+
+test_expect_success 'record a resolution' '
+	cat > a1 <<- EOF &&
+	alpha
+	--beta--
+	gamma
+	EOF
+	sed -e s/alpha/ALPHA/ <a1 >a2 &&
+	git rerere 2>actual
+'
+
+test_expect_success 'postimage must exist' '
+	test -f .git/rr-cache/$sha1/postimage
+'
+
+test_expect_success 'same resolution recorded twice' '
+	test $(grep "Recorded resolution" actual | wc -l) = 2 &&
+	test $(ls .git/rr-cache | wc -w) = 1
+'
+
+test_expect_success 'repeat merge' '
+	git reset --hard &&
+	test_must_fail git merge first
+'
+
+test_expect_failure 'both files are resolved' '
+	! grep ===== a1 a2
+'
+
+test_done
-- 
1.7.2.63.g079547