more D/F conflict tests

Before starting to muck with this code, let's expose the current
breakages that we intend to fix.

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

t/t1012-read-tree-df.sh

@@ -0,0 +1,102 @@
+#!/bin/sh
+
+test_description='read-tree D/F conflict corner cases'
+
+. ./test-lib.sh
+
+maketree () {
+	(
+		rm -f .git/index .git/index.lock &&
+		git clean -d -f -f -q -x &&
+		name="$1" &&
+		shift &&
+		for it
+		do
+			path=$(expr "$it" : '\([^:]*\)') &&
+			mkdir -p $(dirname "$path") &&
+			echo "$it" >"$path" &&
+			git update-index --add "$path" || exit
+		done &&
+		git tag "$name" $(git write-tree)
+	)
+}
+
+settree () {
+	rm -f .git/index .git/index.lock &&
+	git clean -d -f -f -q -x &&
+	git read-tree "$1" &&
+	git checkout-index -f -q -u -a &&
+	git update-index --refresh
+}
+
+checkindex () {
+	git ls-files -s |
+	sed "s|^[0-7][0-7]* $_x40 \([0-3]\)	|\1 |" >current &&
+	cat >expect &&
+	test_cmp expect current
+}
+
+test_expect_success setup '
+	maketree O-000 a/b-2/c/d a/b/c/d a/x &&
+	maketree A-000 a/b-2/c/d a/b/c/d a/x &&
+	maketree A-001 a/b-2/c/d a/b/c/d a/b/c/e a/x &&
+	maketree B-000 a/b-2/c/d a/b     a/x &&
+
+	maketree O-010 t-0     t/1  t/2 t=3 &&
+	maketree A-010 t-0 t            t=3 &&
+	maketree B-010         t/1:     t=3: &&
+
+	maketree O-020 ds/dma/ioat.c ds/dma/ioat_dca.c &&
+	maketree A-020 ds/dma/ioat/Makefile ds/dma/ioat/registers.h &&
+	:
+'
+
+test_expect_failure '3-way (1)' '
+	settree A-000 &&
+	git read-tree -m -u O-000 A-000 B-000 &&
+	checkindex <<-EOF
+	3 a/b
+	0 a/b-2/c/d
+	1 a/b/c/d
+	2 a/b/c/d
+	0 a/x
+	EOF
+'
+
+test_expect_failure '3-way (2)' '
+	settree A-001 &&
+	git read-tree -m -u O-000 A-001 B-000 &&
+	checkindex <<-EOF
+	3 a/b
+	0 a/b-2/c/d
+	1 a/b/c/d
+	2 a/b/c/d
+	2 a/b/c/e
+	0 a/x
+	EOF
+'
+
+test_expect_success '3-way (3)' '
+	settree A-010 &&
+	git read-tree -m -u O-010 A-010 B-010 &&
+	checkindex <<-EOF
+	2 t
+	1 t-0
+	2 t-0
+	1 t/1
+	3 t/1
+	1 t/2
+	0 t=3
+	EOF
+'
+
+test_expect_success '2-way (1)' '
+	settree O-020 &&
+	git read-tree -m -u O-020 A-020 &&
+	checkindex <<-EOF
+	0 ds/dma/ioat/Makefile
+	0 ds/dma/ioat/registers.h
+	EOF
+'
+
+test_done