Merge branch 'bc/hash-independent-tests-part-6'

Test updates to prepare for SHA-2 transition continues.

* bc/hash-independent-tests-part-6:
  t4048: abstract away SHA-1-specific constants
  t4045: make hash-size independent
  t4044: update test to work with SHA-256
  t4039: abstract away SHA-1-specific constants
  t4038: abstract away SHA-1 specific constants
  t4034: abstract away SHA-1-specific constants
  t4027: make hash-size independent
  t4015: abstract away SHA-1-specific constants
  t4011: abstract away SHA-1-specific constants
  t4010: abstract away SHA-1-specific constants
  t3429: remove SHA1 annotation
  t1305: avoid comparing extensions
  rev-parse: add a --show-object-format option
  t/oid-info: add empty tree and empty blob values
  t/oid-info: allow looking up hash algorithm name

16 files changed, 277 insertions, 155 deletions

diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index e72d332b83..9985477efe 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -274,6 +274,13 @@ print a message to stderr and exit with nonzero status.
 	Show the path to the shared index file in split index mode, or
 	empty if not in split-index mode.
 
+--show-object-format[=(storage|input|output)]::
+	Show the object format (hash algorithm) used for the repository
+	for storage inside the `.git` directory, input, or output. For
+	input, multiple algorithms may be printed, space-separated.
+	If not specified, the default is "storage".
+
+
 Other Options
 ~~~~~~~~~~~~~
 
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 308c67e4fc..85ce2095bf 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -919,6 +919,17 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				show_datestring("--min-age=", arg);
 				continue;
 			}
+			if (opt_with_value(arg, "--show-object-format", &arg)) {
+				const char *val = arg ? arg : "storage";
+
+				if (strcmp(val, "storage") &&
+				    strcmp(val, "input") &&
+				    strcmp(val, "output"))
+					die("unknown mode for --show-object-format: %s",
+					    arg);
+				puts(the_hash_algo->name);
+				continue;
+			}
 			if (show_flag(arg) && verify)
 				die_no_single_rev(quiet);
 			continue;
diff --git a/t/oid-info/hash-info b/t/oid-info/hash-info
index ccdbfdf974..d0736dd1a0 100644
--- a/t/oid-info/hash-info
+++ b/t/oid-info/hash-info
@@ -6,3 +6,12 @@ hexsz sha256:64
 
 zero sha1:0000000000000000000000000000000000000000
 zero sha256:0000000000000000000000000000000000000000000000000000000000000000
+
+algo sha1:sha1
+algo sha256:sha256
+
+empty_blob sha1:e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
+empty_blob sha256:473a0f4c3be8a93681a267e3b1e9a7dcda1185436fe141f7749120a303721813
+
+empty_tree sha1:4b825dc642cb6eb9a060e54bf8d69288fbee4904
+empty_tree sha256:6ef19b41225c5369f1c104d45d8d85efa9b057b53b14b4b9b939dd74decc5321
diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
index d20b4d150d..f1e1b289f9 100755
--- a/t/t1305-config-include.sh
+++ b/t/t1305-config-include.sh
@@ -63,7 +63,7 @@ test_expect_success 'listing includes option and expansion' '
 	test.one=1
 	EOF
 	git config --list >actual.full &&
-	grep -v ^core actual.full >actual &&
+	grep -v -e ^core -e ^extensions actual.full >actual &&
 	test_cmp expect actual
 '
 
diff --git a/t/t1500-rev-parse.sh b/t/t1500-rev-parse.sh
index 01abee533d..0177fd815c 100755
--- a/t/t1500-rev-parse.sh
+++ b/t/t1500-rev-parse.sh
@@ -59,6 +59,7 @@ test_rev_parse () {
 ROOT=$(pwd)
 
 test_expect_success 'setup' '
+	test_oid_init &&
 	mkdir -p sub/dir work &&
 	cp -R .git repo.git
 '
@@ -131,6 +132,20 @@ test_expect_success 'rev-parse --is-shallow-repository in non-shallow repo' '
 	test_cmp expect actual
 '
 
+test_expect_success 'rev-parse --show-object-format in repo' '
+	echo "$(test_oid algo)" >expect &&
+	git rev-parse --show-object-format >actual &&
+	test_cmp expect actual &&
+	git rev-parse --show-object-format=storage >actual &&
+	test_cmp expect actual &&
+	git rev-parse --show-object-format=input >actual &&
+	test_cmp expect actual &&
+	git rev-parse --show-object-format=output >actual &&
+	test_cmp expect actual &&
+	test_must_fail git rev-parse --show-object-format=squeamish-ossifrage 2>err &&
+	grep "unknown mode for --show-object-format: squeamish-ossifrage" err
+'
+
 test_expect_success 'showing the superproject correctly' '
 	git rev-parse --show-superproject-working-tree >out &&
 	test_must_be_empty out &&
diff --git a/t/t3429-rebase-edit-todo.sh b/t/t3429-rebase-edit-todo.sh
index 8739cb60a7..aaeac6eade 100755
--- a/t/t3429-rebase-edit-todo.sh
+++ b/t/t3429-rebase-edit-todo.sh
@@ -17,7 +17,7 @@ test_expect_success 'rebase exec modifies rebase-todo' '
 	test -e F
 '
 
-test_expect_success SHA1 'loose object cache vs re-reading todo list' '
+test_expect_success 'loose object cache vs re-reading todo list' '
 	GIT_REBASE_TODO=.git/rebase-merge/git-rebase-todo &&
 	export GIT_REBASE_TODO &&
 	write_script append-todo.sh <<-\EOS &&
diff --git a/t/t4010-diff-pathspec.sh b/t/t4010-diff-pathspec.sh
index 281f8fad0c..e5ca359edf 100755
--- a/t/t4010-diff-pathspec.sh
+++ b/t/t4010-diff-pathspec.sh
@@ -17,11 +17,15 @@ test_expect_success \
     'echo frotz >file0 &&
      mkdir path1 &&
      echo rezrov >path1/file1 &&
+     before0=$(git hash-object file0) &&
+     before1=$(git hash-object path1/file1) &&
      git update-index --add file0 path1/file1 &&
      tree=$(git write-tree) &&
      echo "$tree" &&
      echo nitfol >file0 &&
      echo yomin >path1/file1 &&
+     after0=$(git hash-object file0) &&
+     after1=$(git hash-object path1/file1) &&
      git update-index file0 path1/file1'
 
 cat >expected <<\EOF
@@ -31,32 +35,32 @@ test_expect_success \
     'git diff-index --cached $tree -- path >current &&
      compare_diff_raw current expected'
 
-cat >expected <<\EOF
-:100644 100644 766498d93a4b06057a8e49d23f4068f1170ff38f 0a41e115ab61be0328a19b29f18cdcb49338d516 M	path1/file1
+cat >expected <<EOF
+:100644 100644 $before1 $after1 M	path1/file1
 EOF
 test_expect_success \
     'limit to path1 should show path1/file1' \
     'git diff-index --cached $tree -- path1 >current &&
      compare_diff_raw current expected'
 
-cat >expected <<\EOF
-:100644 100644 766498d93a4b06057a8e49d23f4068f1170ff38f 0a41e115ab61be0328a19b29f18cdcb49338d516 M	path1/file1
+cat >expected <<EOF
+:100644 100644 $before1 $after1 M	path1/file1
 EOF
 test_expect_success \
     'limit to path1/ should show path1/file1' \
     'git diff-index --cached $tree -- path1/ >current &&
      compare_diff_raw current expected'
 
-cat >expected <<\EOF
-:100644 100644 766498d93a4b06057a8e49d23f4068f1170ff38f 0a41e115ab61be0328a19b29f18cdcb49338d516 M	path1/file1
+cat >expected <<EOF
+:100644 100644 $before1 $after1 M	path1/file1
 EOF
 test_expect_success \
     '"*file1" should show path1/file1' \
     'git diff-index --cached $tree -- "*file1" >current &&
      compare_diff_raw current expected'
 
-cat >expected <<\EOF
-:100644 100644 8e4020bb5a8d8c873b25de15933e75cc0fc275df dca6b92303befc93086aa025d90a5facd7eb2812 M	file0
+cat >expected <<EOF
+:100644 100644 $before0 $after0 M	file0
 EOF
 test_expect_success \
     'limit to file0 should show file0' \
diff --git a/t/t4011-diff-symlink.sh b/t/t4011-diff-symlink.sh
index 5ae19b987d..717034bb50 100755
--- a/t/t4011-diff-symlink.sh
+++ b/t/t4011-diff-symlink.sh
@@ -9,11 +9,24 @@ test_description='Test diff of symlinks.
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/diff-lib.sh
 
+# Print the short OID of a symlink with the given name.
+symlink_oid () {
+	local oid=$(printf "%s" "$1" | git hash-object --stdin) &&
+	git rev-parse --short "$oid"
+}
+
+# Print the short OID of the given file.
+short_oid () {
+	local oid=$(git hash-object "$1") &&
+	git rev-parse --short "$oid"
+}
+
 test_expect_success 'diff new symlink and file' '
-	cat >expected <<-\EOF &&
+	symlink=$(symlink_oid xyzzy) &&
+	cat >expected <<-EOF &&
 	diff --git a/frotz b/frotz
 	new file mode 120000
-	index 0000000..7c465af
+	index 0000000..$symlink
 	--- /dev/null
 	+++ b/frotz
 	@@ -0,0 +1 @@
@@ -21,7 +34,7 @@ test_expect_success 'diff new symlink and file' '
 	\ No newline at end of file
 	diff --git a/nitfol b/nitfol
 	new file mode 100644
-	index 0000000..7c465af
+	index 0000000..$symlink
 	--- /dev/null
 	+++ b/nitfol
 	@@ -0,0 +1 @@
@@ -46,10 +59,10 @@ test_expect_success 'diff unchanged symlink and file'  '
 '
 
 test_expect_success 'diff removed symlink and file' '
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	diff --git a/frotz b/frotz
 	deleted file mode 120000
-	index 7c465af..0000000
+	index $symlink..0000000
 	--- a/frotz
 	+++ /dev/null
 	@@ -1 +0,0 @@
@@ -57,7 +70,7 @@ test_expect_success 'diff removed symlink and file' '
 	\ No newline at end of file
 	diff --git a/nitfol b/nitfol
 	deleted file mode 100644
-	index 7c465af..0000000
+	index $symlink..0000000
 	--- a/nitfol
 	+++ /dev/null
 	@@ -1 +0,0 @@
@@ -90,9 +103,10 @@ test_expect_success 'diff identical, but newly created symlink and file' '
 '
 
 test_expect_success 'diff different symlink and file' '
-	cat >expected <<-\EOF &&
+	new=$(symlink_oid yxyyz) &&
+	cat >expected <<-EOF &&
 	diff --git a/frotz b/frotz
-	index 7c465af..df1db54 120000
+	index $symlink..$new 120000
 	--- a/frotz
 	+++ b/frotz
 	@@ -1 +1 @@
@@ -101,7 +115,7 @@ test_expect_success 'diff different symlink and file' '
 	+yxyyz
 	\ No newline at end of file
 	diff --git a/nitfol b/nitfol
-	index 7c465af..df1db54 100644
+	index $symlink..$new 100644
 	--- a/nitfol
 	+++ b/nitfol
 	@@ -1 +1 @@
@@ -137,14 +151,16 @@ test_expect_success SYMLINKS 'setup symlinks with attributes' '
 '
 
 test_expect_success SYMLINKS 'symlinks do not respect userdiff config by path' '
-	cat >expect <<-\EOF &&
+	file=$(short_oid file.bin) &&
+	link=$(symlink_oid file.bin) &&
+	cat >expect <<-EOF &&
 	diff --git a/file.bin b/file.bin
 	new file mode 100644
-	index 0000000..d95f3ad
+	index 0000000..$file
 	Binary files /dev/null and b/file.bin differ
 	diff --git a/link.bin b/link.bin
 	new file mode 120000
-	index 0000000..dce41ec
+	index 0000000..$link
 	--- /dev/null
 	+++ b/link.bin
 	@@ -0,0 +1 @@
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 6b087df3dc..eadaf57262 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -16,6 +16,7 @@ test_expect_success "Ray Lehtiniemi's example" '
 	} while (0);
 	EOF
 	git update-index --add x &&
+	before=$(git rev-parse --short $(git hash-object x)) &&
 
 	cat <<-\EOF >x &&
 	do
@@ -24,10 +25,11 @@ test_expect_success "Ray Lehtiniemi's example" '
 	}
 	while (0);
 	EOF
+	after=$(git rev-parse --short $(git hash-object x)) &&
 
-	cat <<-\EOF >expect &&
+	cat <<-EOF >expect &&
 	diff --git a/x b/x
-	index adf3937..6edc172 100644
+	index $before..$after 100644
 	--- a/x
 	+++ b/x
 	@@ -1,3 +1,5 @@
@@ -61,6 +63,7 @@ test_expect_success 'another test, without options' '
 	EOF
 
 	git update-index x &&
+	before=$(git rev-parse --short $(git hash-object x)) &&
 
 	tr "_" " " <<-\EOF >x &&
 	_	whitespace at beginning
@@ -70,10 +73,11 @@ test_expect_success 'another test, without options' '
 	unchanged line
 	CR at end
 	EOF
+	after=$(git rev-parse --short $(git hash-object x)) &&
 
-	tr "Q_" "\015 " <<-\EOF >expect &&
+	tr "Q_" "\015 " <<-EOF >expect &&
 	diff --git a/x b/x
-	index d99af23..22d9f73 100644
+	index $before..$after 100644
 	--- a/x
 	+++ b/x
 	@@ -1,6 +1,6 @@
@@ -108,9 +112,9 @@ test_expect_success 'another test, without options' '
 	git diff -w --ignore-cr-at-eol >out &&
 	test_must_be_empty out &&
 
-	tr "Q_" "\015 " <<-\EOF >expect &&
+	tr "Q_" "\015 " <<-EOF >expect &&
 	diff --git a/x b/x
-	index d99af23..22d9f73 100644
+	index $before..$after 100644
 	--- a/x
 	+++ b/x
 	@@ -1,6 +1,6 @@
@@ -132,9 +136,9 @@ test_expect_success 'another test, without options' '
 	git diff -b --ignore-cr-at-eol >out &&
 	test_cmp expect out &&
 
-	tr "Q_" "\015 " <<-\EOF >expect &&
+	tr "Q_" "\015 " <<-EOF >expect &&
 	diff --git a/x b/x
-	index d99af23..22d9f73 100644
+	index $before..$after 100644
 	--- a/x
 	+++ b/x
 	@@ -1,6 +1,6 @@
@@ -154,9 +158,9 @@ test_expect_success 'another test, without options' '
 	git diff --ignore-space-at-eol --ignore-cr-at-eol >out &&
 	test_cmp expect out &&
 
-	tr "Q_" "\015 " <<-\EOF >expect &&
+	tr "Q_" "\015 " <<-EOF >expect &&
 	diff --git a/x b/x
-	index_d99af23..22d9f73 100644
+	index_$before..$after 100644
 	--- a/x
 	+++ b/x
 	@@ -1,6 +1,6 @@
@@ -786,23 +790,25 @@ test_expect_success 'whitespace-only changes not reported' '
 	test_must_be_empty actual
 '
 
-cat <<EOF >expect
-diff --git a/x b/z
-similarity index NUM%
-rename from x
-rename to z
-index 380c32a..a97b785 100644
-EOF
 test_expect_success 'whitespace-only changes reported across renames' '
 	git reset --hard &&
 	for i in 1 2 3 4 5 6 7 8 9; do echo "$i$i$i$i$i$i"; done >x &&
 	git add x &&
+	before=$(git rev-parse --short $(git hash-object x)) &&
 	git commit -m "base" &&
 	sed -e "5s/^/ /" x >z &&
 	git rm x &&
 	git add z &&
+	after=$(git rev-parse --short $(git hash-object z)) &&
 	git diff -w -M --cached |
 	sed -e "/^similarity index /s/[0-9][0-9]*/NUM/" >actual &&
+	cat <<-EOF >expect &&
+	diff --git a/x b/z
+	similarity index NUM%
+	rename from x
+	rename to z
+	index $before..$after 100644
+	EOF
 	test_cmp expect actual
 '
 
@@ -858,13 +864,15 @@ test_expect_success 'diff that introduces a line with only tabs' '
 	git config core.whitespace blank-at-eol &&
 	git reset --hard &&
 	echo "test" >x &&
+	before=$(git rev-parse --short $(git hash-object x)) &&
 	git commit -m "initial" x &&
 	echo "{NTN}" | tr "NT" "\n\t" >>x &&
+	after=$(git rev-parse --short $(git hash-object x)) &&
 	git diff --color | test_decode_color >current &&
 
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	<BOLD>diff --git a/x b/x<RESET>
-	<BOLD>index 9daeafb..2874b91 100644<RESET>
+	<BOLD>index $before..$after 100644<RESET>
 	<BOLD>--- a/x<RESET>
 	<BOLD>+++ b/x<RESET>
 	<CYAN>@@ -1 +1,4 @@<RESET>
@@ -883,19 +891,21 @@ test_expect_success 'diff that introduces and removes ws breakages' '
 		echo "0. blank-at-eol " &&
 		echo "1. blank-at-eol "
 	} >x &&
+	before=$(git rev-parse --short $(git hash-object x)) &&
 	git commit -a --allow-empty -m preimage &&
 	{
 		echo "0. blank-at-eol " &&
 		echo "1. still-blank-at-eol " &&
 		echo "2. and a new line "
 	} >x &&
+	after=$(git rev-parse --short $(git hash-object x)) &&
 
 	git diff --color |
 	test_decode_color >current &&
 
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	<BOLD>diff --git a/x b/x<RESET>
-	<BOLD>index d0233a2..700886e 100644<RESET>
+	<BOLD>index $before..$after 100644<RESET>
 	<BOLD>--- a/x<RESET>
 	<BOLD>+++ b/x<RESET>
 	<CYAN>@@ -1,2 +1,3 @@<RESET>
@@ -915,16 +925,18 @@ test_expect_success 'ws-error-highlight test setup' '
 		echo "0. blank-at-eol " &&
 		echo "1. blank-at-eol "
 	} >x &&
+	before=$(git rev-parse --short $(git hash-object x)) &&
 	git commit -a --allow-empty -m preimage &&
 	{
 		echo "0. blank-at-eol " &&
 		echo "1. still-blank-at-eol " &&
 		echo "2. and a new line "
 	} >x &&
+	after=$(git rev-parse --short $(git hash-object x)) &&
 
-	cat >expect.default-old <<-\EOF &&
+	cat >expect.default-old <<-EOF &&
 	<BOLD>diff --git a/x b/x<RESET>
-	<BOLD>index d0233a2..700886e 100644<RESET>
+	<BOLD>index $before..$after 100644<RESET>
 	<BOLD>--- a/x<RESET>
 	<BOLD>+++ b/x<RESET>
 	<CYAN>@@ -1,2 +1,3 @@<RESET>
@@ -934,9 +946,9 @@ test_expect_success 'ws-error-highlight test setup' '
 	<GREEN>+<RESET><GREEN>2. and a new line<RESET><BLUE> <RESET>
 	EOF
 
-	cat >expect.all <<-\EOF &&
+	cat >expect.all <<-EOF &&
 	<BOLD>diff --git a/x b/x<RESET>
-	<BOLD>index d0233a2..700886e 100644<RESET>
+	<BOLD>index $before..$after 100644<RESET>
 	<BOLD>--- a/x<RESET>
 	<BOLD>+++ b/x<RESET>
 	<CYAN>@@ -1,2 +1,3 @@<RESET>
@@ -946,9 +958,9 @@ test_expect_success 'ws-error-highlight test setup' '
 	<GREEN>+<RESET><GREEN>2. and a new line<RESET><BLUE> <RESET>
 	EOF
 
-	cat >expect.none <<-\EOF
+	cat >expect.none <<-EOF
 	<BOLD>diff --git a/x b/x<RESET>
-	<BOLD>index d0233a2..700886e 100644<RESET>
+	<BOLD>index $before..$after 100644<RESET>
 	<BOLD>--- a/x<RESET>
 	<BOLD>+++ b/x<RESET>
 	<CYAN>@@ -1,2 +1,3 @@<RESET>
@@ -1022,14 +1034,15 @@ test_expect_success 'detect moved code, complete file' '
 	EOF
 	git add test.c &&
 	git commit -m "add main function" &&
+	file=$(git rev-parse --short HEAD:test.c) &&
 	git mv test.c main.c &&
 	test_config color.diff.oldMoved "normal red" &&
 	test_config color.diff.newMoved "normal green" &&
 	git diff HEAD --color-moved=zebra --color --no-renames | test_decode_color >actual &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	<BOLD>diff --git a/main.c b/main.c<RESET>
 	<BOLD>new file mode 100644<RESET>
-	<BOLD>index 0000000..a986c57<RESET>
+	<BOLD>index 0000000..$file<RESET>
 	<BOLD>--- /dev/null<RESET>
 	<BOLD>+++ b/main.c<RESET>
 	<CYAN>@@ -0,0 +1,5 @@<RESET>
@@ -1040,7 +1053,7 @@ test_expect_success 'detect moved code, complete file' '
 	<BGREEN>+<RESET><BGREEN>}<RESET>
 	<BOLD>diff --git a/test.c b/test.c<RESET>
 	<BOLD>deleted file mode 100644<RESET>
-	<BOLD>index a986c57..0000000<RESET>
+	<BOLD>index $file..0000000<RESET>
 	<BOLD>--- a/test.c<RESET>
 	<BOLD>+++ /dev/null<RESET>
 	<CYAN>@@ -1,5 +0,0 @@<RESET>
@@ -1094,6 +1107,8 @@ test_expect_success 'detect malicious moved code, inside file' '
 	EOF
 	git add main.c test.c &&
 	git commit -m "add main and test file" &&
+	before_main=$(git rev-parse --short HEAD:main.c) &&
+	before_test=$(git rev-parse --short HEAD:test.c) &&
 	cat <<-\EOF >main.c &&
 		#include<stdio.h>
 		int stuff()
@@ -1126,10 +1141,12 @@ test_expect_success 'detect malicious moved code, inside file' '
 			bar();
 		}
 	EOF
+	after_main=$(git rev-parse --short $(git hash-object main.c)) &&
+	after_test=$(git rev-parse --short $(git hash-object test.c)) &&
 	git diff HEAD --no-renames --color-moved=zebra --color | test_decode_color >actual &&
-	cat <<-\EOF >expected &&
+	cat <<-EOF >expected &&
 	<BOLD>diff --git a/main.c b/main.c<RESET>
-	<BOLD>index 27a619c..7cf9336 100644<RESET>
+	<BOLD>index $before_main..$after_main 100644<RESET>
 	<BOLD>--- a/main.c<RESET>
 	<BOLD>+++ b/main.c<RESET>
 	<CYAN>@@ -5,13 +5,6 @@<RESET> <RESET>printf("Hello ");<RESET>
@@ -1147,7 +1164,7 @@ test_expect_success 'detect malicious moved code, inside file' '
 	 {<RESET>
 	 foo();<RESET>
 	<BOLD>diff --git a/test.c b/test.c<RESET>
-	<BOLD>index 1dc1d85..2bedec9 100644<RESET>
+	<BOLD>index $before_test..$after_test 100644<RESET>
 	<BOLD>--- a/test.c<RESET>
 	<BOLD>+++ b/test.c<RESET>
 	<CYAN>@@ -4,6 +4,13 @@<RESET> <RESET>int bar()<RESET>
@@ -1176,9 +1193,9 @@ test_expect_success 'plain moved code, inside file' '
 	test_config color.diff.newMovedAlternative "yellow" &&
 	# needs previous test as setup
 	git diff HEAD --no-renames --color-moved=plain --color | test_decode_color >actual &&
-	cat <<-\EOF >expected &&
+	cat <<-EOF >expected &&
 	<BOLD>diff --git a/main.c b/main.c<RESET>
-	<BOLD>index 27a619c..7cf9336 100644<RESET>
+	<BOLD>index $before_main..$after_main 100644<RESET>
 	<BOLD>--- a/main.c<RESET>
 	<BOLD>+++ b/main.c<RESET>
 	<CYAN>@@ -5,13 +5,6 @@<RESET> <RESET>printf("Hello ");<RESET>
@@ -1196,7 +1213,7 @@ test_expect_success 'plain moved code, inside file' '
 	 {<RESET>
 	 foo();<RESET>
 	<BOLD>diff --git a/test.c b/test.c<RESET>
-	<BOLD>index 1dc1d85..2bedec9 100644<RESET>
+	<BOLD>index $before_test..$after_test 100644<RESET>
 	<BOLD>--- a/test.c<RESET>
 	<BOLD>+++ b/test.c<RESET>
 	<CYAN>@@ -4,6 +4,13 @@<RESET> <RESET>int bar()<RESET>
diff --git a/t/t4027-diff-submodule.sh b/t/t4027-diff-submodule.sh
index 9aa8e2b39b..e29deaf4a5 100755
--- a/t/t4027-diff-submodule.sh
+++ b/t/t4027-diff-submodule.sh
@@ -6,6 +6,7 @@ test_description='difference in submodules'
 . "$TEST_DIRECTORY"/diff-lib.sh
 
 test_expect_success setup '
+	test_oid_init &&
 	test_tick &&
 	test_create_repo sub &&
 	(
@@ -36,7 +37,8 @@ test_expect_success setup '
 '
 
 test_expect_success 'git diff --raw HEAD' '
-	git diff --raw --abbrev=40 HEAD >actual &&
+	hexsz=$(test_oid hexsz) &&
+	git diff --raw --abbrev=$hexsz HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -245,23 +247,21 @@ test_expect_success 'git diff (empty submodule dir)' '
 '
 
 test_expect_success 'conflicted submodule setup' '
-
-	# 39 efs
-	c=fffffffffffffffffffffffffffffffffffffff &&
+	c=$(test_oid ff_1) &&
 	(
 		echo "000000 $ZERO_OID 0	sub" &&
 		echo "160000 1$c 1	sub" &&
 		echo "160000 2$c 2	sub" &&
 		echo "160000 3$c 3	sub"
 	) | git update-index --index-info &&
-	echo >expect.nosub '\''diff --cc sub
+	echo >expect.nosub "diff --cc sub
 index 2ffffff,3ffffff..0000000
 --- a/sub
 +++ b/sub
 @@@ -1,1 -1,1 +1,1 @@@
-- Subproject commit 2fffffffffffffffffffffffffffffffffffffff
- -Subproject commit 3fffffffffffffffffffffffffffffffffffffff
-++Subproject commit 0000000000000000000000000000000000000000'\'' &&
+- Subproject commit 2$c
+ -Subproject commit 3$c
+++Subproject commit $ZERO_OID" &&
 
 	hh=$(git rev-parse HEAD) &&
 	sed -e "s/$ZERO_OID/$hh/" expect.nosub >expect.withsub
diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh
index 9a93c2a3e0..fb145aa173 100755
--- a/t/t4034-diff-words.sh
+++ b/t/t4034-diff-words.sh
@@ -19,9 +19,11 @@ cat >post.simple <<-\EOF
 
 	aeff = aeff * ( aaa )
 EOF
-cat >expect.letter-runs-are-words <<-\EOF
+pre=$(git rev-parse --short $(git hash-object pre.simple))
+post=$(git rev-parse --short $(git hash-object post.simple))
+cat >expect.letter-runs-are-words <<-EOF
 	<BOLD>diff --git a/pre b/post<RESET>
-	<BOLD>index 330b04f..5ed8eff 100644<RESET>
+	<BOLD>index $pre..$post 100644<RESET>
 	<BOLD>--- a/pre<RESET>
 	<BOLD>+++ b/post<RESET>
 	<CYAN>@@ -1,3 +1,7 @@<RESET>
@@ -33,9 +35,9 @@ cat >expect.letter-runs-are-words <<-\EOF
 
 	<GREEN>aeff = aeff * ( aaa<RESET> )
 EOF
-cat >expect.non-whitespace-is-word <<-\EOF
+cat >expect.non-whitespace-is-word <<-EOF
 	<BOLD>diff --git a/pre b/post<RESET>
-	<BOLD>index 330b04f..5ed8eff 100644<RESET>
+	<BOLD>index $pre..$post 100644<RESET>
 	<BOLD>--- a/pre<RESET>
 	<BOLD>+++ b/post<RESET>
 	<CYAN>@@ -1,3 +1,7 @@<RESET>
@@ -49,9 +51,12 @@ cat >expect.non-whitespace-is-word <<-\EOF
 EOF
 
 word_diff () {
+	pre=$(git rev-parse --short $(git hash-object pre)) &&
+	post=$(git rev-parse --short $(git hash-object post)) &&
 	test_must_fail git diff --no-index "$@" pre post >output &&
 	test_decode_color <output >output.decrypted &&
-	test_cmp expect output.decrypted
+	sed -e "2s/index [^ ]*/index $pre..$post/" expect >expected
+	test_cmp expected output.decrypted
 }
 
 test_language_driver () {
@@ -77,9 +82,9 @@ test_expect_success 'set up pre and post with runs of whitespace' '
 '
 
 test_expect_success 'word diff with runs of whitespace' '
-	cat >expect <<-\EOF &&
+	cat >expect <<-EOF &&
 		<BOLD>diff --git a/pre b/post<RESET>
-		<BOLD>index 330b04f..5ed8eff 100644<RESET>
+		<BOLD>index $pre..$post 100644<RESET>
 		<BOLD>--- a/pre<RESET>
 		<BOLD>+++ b/post<RESET>
 		<CYAN>@@ -1,3 +1,7 @@<RESET>
@@ -97,9 +102,9 @@ test_expect_success 'word diff with runs of whitespace' '
 '
 
 test_expect_success '--word-diff=porcelain' '
-	sed 's/#.*$//' >expect <<-\EOF &&
+	sed 's/#.*$//' >expect <<-EOF &&
 		diff --git a/pre b/post
-		index 330b04f..5ed8eff 100644
+		index $pre..$post 100644
 		--- a/pre
 		+++ b/post
 		@@ -1,3 +1,7 @@
@@ -121,9 +126,9 @@ test_expect_success '--word-diff=porcelain' '
 '
 
 test_expect_success '--word-diff=plain' '
-	cat >expect <<-\EOF &&
+	cat >expect <<-EOF &&
 		diff --git a/pre b/post
-		index 330b04f..5ed8eff 100644
+		index $pre..$post 100644
 		--- a/pre
 		+++ b/post
 		@@ -1,3 +1,7 @@
@@ -140,9 +145,9 @@ test_expect_success '--word-diff=plain' '
 '
 
 test_expect_success '--word-diff=plain --color' '
-	cat >expect <<-\EOF &&
+	cat >expect <<-EOF &&
 		<BOLD>diff --git a/pre b/post<RESET>
-		<BOLD>index 330b04f..5ed8eff 100644<RESET>
+		<BOLD>index $pre..$post 100644<RESET>
 		<BOLD>--- a/pre<RESET>
 		<BOLD>+++ b/post<RESET>
 		<CYAN>@@ -1,3 +1,7 @@<RESET>
@@ -158,9 +163,9 @@ test_expect_success '--word-diff=plain --color' '
 '
 
 test_expect_success 'word diff without context' '
-	cat >expect <<-\EOF &&
+	cat >expect <<-EOF &&
 		<BOLD>diff --git a/pre b/post<RESET>
-		<BOLD>index 330b04f..5ed8eff 100644<RESET>
+		<BOLD>index $pre..$post 100644<RESET>
 		<BOLD>--- a/pre<RESET>
 		<BOLD>+++ b/post<RESET>
 		<CYAN>@@ -1 +1 @@<RESET>
@@ -207,9 +212,9 @@ test_expect_success 'command-line overrides config' '
 '
 
 test_expect_success 'command-line overrides config: --word-diff-regex' '
-	cat >expect <<-\EOF &&
+	cat >expect <<-EOF &&
 		<BOLD>diff --git a/pre b/post<RESET>
-		<BOLD>index 330b04f..5ed8eff 100644<RESET>
+		<BOLD>index $pre..$post 100644<RESET>
 		<BOLD>--- a/pre<RESET>
 		<BOLD>+++ b/post<RESET>
 		<CYAN>@@ -1,3 +1,7 @@<RESET>
@@ -234,9 +239,9 @@ test_expect_success 'setup: remove diff driver regex' '
 '
 
 test_expect_success 'use configured regex' '
-	cat >expect <<-\EOF &&
+	cat >expect <<-EOF &&
 		<BOLD>diff --git a/pre b/post<RESET>
-		<BOLD>index 330b04f..5ed8eff 100644<RESET>
+		<BOLD>index $pre..$post 100644<RESET>
 		<BOLD>--- a/pre<RESET>
 		<BOLD>+++ b/post<RESET>
 		<CYAN>@@ -1,3 +1,7 @@<RESET>
@@ -254,9 +259,11 @@ test_expect_success 'use configured regex' '
 test_expect_success 'test parsing words for newline' '
 	echo "aaa (aaa)" >pre &&
 	echo "aaa (aaa) aaa" >post &&
-	cat >expect <<-\EOF &&
+	pre=$(git rev-parse --short $(git hash-object pre)) &&
+	post=$(git rev-parse --short $(git hash-object post)) &&
+	cat >expect <<-EOF &&
 		<BOLD>diff --git a/pre b/post<RESET>
-		<BOLD>index c29453b..be22f37 100644<RESET>
+		<BOLD>index $pre..$post 100644<RESET>
 		<BOLD>--- a/pre<RESET>
 		<BOLD>+++ b/post<RESET>
 		<CYAN>@@ -1 +1 @@<RESET>
@@ -268,9 +275,11 @@ test_expect_success 'test parsing words for newline' '
 test_expect_success 'test when words are only removed at the end' '
 	echo "(:" >pre &&
 	echo "(" >post &&
-	cat >expect <<-\EOF &&
+	pre=$(git rev-parse --short $(git hash-object pre)) &&
+	post=$(git rev-parse --short $(git hash-object post)) &&
+	cat >expect <<-EOF &&
 		<BOLD>diff --git a/pre b/post<RESET>
-		<BOLD>index 289cb9d..2d06f37 100644<RESET>
+		<BOLD>index $pre..$post 100644<RESET>
 		<BOLD>--- a/pre<RESET>
 		<BOLD>+++ b/post<RESET>
 		<CYAN>@@ -1 +1 @@<RESET>
@@ -282,9 +291,11 @@ test_expect_success 'test when words are only removed at the end' '
 test_expect_success '--word-diff=none' '
 	echo "(:" >pre &&
 	echo "(" >post &&
-	cat >expect <<-\EOF &&
+	pre=$(git rev-parse --short $(git hash-object pre)) &&
+	post=$(git rev-parse --short $(git hash-object post)) &&
+	cat >expect <<-EOF &&
 		diff --git a/pre b/post
-		index 289cb9d..2d06f37 100644
+		index $pre..$post 100644
 		--- a/pre
 		+++ b/post
 		@@ -1 +1 @@
@@ -317,16 +328,6 @@ test_language_driver ruby
 test_language_driver tex
 
 test_expect_success 'word-diff with diff.sbe' '
-	cat >expect <<-\EOF &&
-	diff --git a/pre b/post
-	index a1a53b5..bc8fe6d 100644
-	--- a/pre
-	+++ b/post
-	@@ -1,3 +1,3 @@
-	a
-
-	[-b-]{+c+}
-	EOF
 	cat >pre <<-\EOF &&
 	a
 
@@ -337,21 +338,35 @@ test_expect_success 'word-diff with diff.sbe' '
 
 	c
 	EOF
+	pre=$(git rev-parse --short $(git hash-object pre)) &&
+	post=$(git rev-parse --short $(git hash-object post)) &&
+	cat >expect <<-EOF &&
+	diff --git a/pre b/post
+	index $pre..$post 100644
+	--- a/pre
+	+++ b/post
+	@@ -1,3 +1,3 @@
+	a
+
+	[-b-]{+c+}
+	EOF
 	test_config diff.suppress-blank-empty true &&
 	word_diff --word-diff=plain
 '
 
 test_expect_success 'word-diff with no newline at EOF' '
-	cat >expect <<-\EOF &&
+	printf "%s" "a a a a a" >pre &&
+	printf "%s" "a a ab a a" >post &&
+	pre=$(git rev-parse --short $(git hash-object pre)) &&
+	post=$(git rev-parse --short $(git hash-object post)) &&
+	cat >expect <<-EOF &&
 	diff --git a/pre b/post
-	index 7bf316e..3dd0303 100644
+	index $pre..$post 100644
 	--- a/pre
 	+++ b/post
 	@@ -1 +1 @@
 	a a [-a-]{+ab+} a a
 	EOF
-	printf "%s" "a a a a a" >pre &&
-	printf "%s" "a a ab a a" >post &&
 	word_diff --word-diff=plain
 '
 
diff --git a/t/t4038-diff-combined.sh b/t/t4038-diff-combined.sh
index b9d876efa2..b5a56895e8 100755
--- a/t/t4038-diff-combined.sh
+++ b/t/t4038-diff-combined.sh
@@ -440,11 +440,13 @@ test_expect_success 'setup for --combined-all-paths' '
 	git branch side2c &&
 	git checkout side1c &&
 	test_seq 1 10 >filename-side1c &&
+	side1cf=$(git hash-object filename-side1c) &&
 	git add filename-side1c &&
 	git commit -m with &&
 	git checkout side2c &&
 	test_seq 1 9 >filename-side2c &&
 	echo ten >>filename-side2c &&
+	side2cf=$(git hash-object filename-side2c) &&
 	git add filename-side2c &&
 	git commit -m iam &&
 	git checkout -b mergery side1c &&
@@ -452,13 +454,14 @@ test_expect_success 'setup for --combined-all-paths' '
 	git rm filename-side1c &&
 	echo eleven >>filename-side2c &&
 	git mv filename-side2c filename-merged &&
+	mergedf=$(git hash-object filename-merged) &&
 	git add filename-merged &&
 	git commit
 '
 
 test_expect_success '--combined-all-paths and --raw' '
-	cat <<-\EOF >expect &&
-	::100644 100644 100644 f00c965d8307308469e537302baa73048488f162 088bd5d92c2a8e0203ca8e7e4c2a5c692f6ae3f7 333b9c62519f285e1854830ade0fe1ef1d40ee1b RR	filename-side1c	filename-side2c	filename-merged
+	cat <<-EOF >expect &&
+	::100644 100644 100644 $side1cf $side2cf $mergedf RR	filename-side1c	filename-side2c	filename-merged
 	EOF
 	git diff-tree -c -M --raw --combined-all-paths HEAD >actual.tmp &&
 	sed 1d <actual.tmp >actual &&
@@ -482,11 +485,13 @@ test_expect_success FUNNYNAMES 'setup for --combined-all-paths with funny names'
 	git checkout side1d &&
 	test_seq 1 10 >"$(printf "file\twith\ttabs")" &&
 	git add file* &&
+	side1df=$(git hash-object *tabs) &&
 	git commit -m with &&
 	git checkout side2d &&
 	test_seq 1 9 >"$(printf "i\tam\ttabbed")" &&
 	echo ten >>"$(printf "i\tam\ttabbed")" &&
 	git add *tabbed &&
+	side2df=$(git hash-object *tabbed) &&
 	git commit -m iam &&
 	git checkout -b funny-names-mergery side1d &&
 	git merge --no-commit side2d &&
@@ -494,12 +499,14 @@ test_expect_success FUNNYNAMES 'setup for --combined-all-paths with funny names'
 	echo eleven >>"$(printf "i\tam\ttabbed")" &&
 	git mv "$(printf "i\tam\ttabbed")" "$(printf "fickle\tnaming")" &&
 	git add fickle* &&
-	git commit
+	headf=$(git hash-object fickle*) &&
+	git commit &&
+	head=$(git rev-parse HEAD)
 '
 
 test_expect_success FUNNYNAMES '--combined-all-paths and --raw and funny names' '
-	cat <<-\EOF >expect &&
-	::100644 100644 100644 f00c965d8307308469e537302baa73048488f162 088bd5d92c2a8e0203ca8e7e4c2a5c692f6ae3f7 333b9c62519f285e1854830ade0fe1ef1d40ee1b RR	"file\twith\ttabs"	"i\tam\ttabbed"	"fickle\tnaming"
+	cat <<-EOF >expect &&
+	::100644 100644 100644 $side1df $side2df $headf RR	"file\twith\ttabs"	"i\tam\ttabbed"	"fickle\tnaming"
 	EOF
 	git diff-tree -c -M --raw --combined-all-paths HEAD >actual.tmp &&
 	sed 1d <actual.tmp >actual &&
@@ -507,7 +514,7 @@ test_expect_success FUNNYNAMES '--combined-all-paths and --raw and funny names'
 '
 
 test_expect_success FUNNYNAMES '--combined-all-paths and --raw -and -z and funny names' '
-	printf "aaf8087c3cbd4db8e185a2d074cf27c53cfb75d7\0::100644 100644 100644 f00c965d8307308469e537302baa73048488f162 088bd5d92c2a8e0203ca8e7e4c2a5c692f6ae3f7 333b9c62519f285e1854830ade0fe1ef1d40ee1b RR\0file\twith\ttabs\0i\tam\ttabbed\0fickle\tnaming\0" >expect &&
+	printf "$head\0::100644 100644 100644 $side1df $side2df $headf RR\0file\twith\ttabs\0i\tam\ttabbed\0fickle\tnaming\0" >expect &&
 	git diff-tree -c -M --raw --combined-all-paths -z HEAD >actual &&
 	test_cmp expect actual
 '
diff --git a/t/t4039-diff-assume-unchanged.sh b/t/t4039-diff-assume-unchanged.sh
index 53ac44b0f0..0eb0314a8b 100755
--- a/t/t4039-diff-assume-unchanged.sh
+++ b/t/t4039-diff-assume-unchanged.sh
@@ -12,6 +12,7 @@ test_expect_success 'setup' '
 	git commit -m zero &&
 	echo one > one &&
 	echo two > two &&
+	blob=$(git hash-object one) &&
 	git add one two &&
 	git commit -m onetwo &&
 	git update-index --assume-unchanged one &&
@@ -20,7 +21,7 @@ test_expect_success 'setup' '
 '
 
 test_expect_success 'diff-index does not examine assume-unchanged entries' '
-	git diff-index HEAD^ -- one | grep -q 5626abf0f72e58d7a153368ba57db4c673c0e171
+	git diff-index HEAD^ -- one | grep -q $blob
 '
 
 test_expect_success 'diff-files does not examine assume-unchanged entries' '
diff --git a/t/t4044-diff-index-unique-abbrev.sh b/t/t4044-diff-index-unique-abbrev.sh
index 647905e01f..4701796d10 100755
--- a/t/t4044-diff-index-unique-abbrev.sh
+++ b/t/t4044-diff-index-unique-abbrev.sh
@@ -3,34 +3,48 @@
 test_description='test unique sha1 abbreviation on "index from..to" line'
 . ./test-lib.sh
 
-if ! test_have_prereq SHA1
-then
-       skip_all='not using SHA-1 for objects'
-       test_done
-fi
-
-cat >expect_initial <<EOF
-100644 blob 51d2738463ea4ca66f8691c91e33ce64b7d41bb1	foo
-EOF
+test_expect_success 'setup' '
+	test_oid_cache <<-EOF &&
+	val1 sha1:4827
+	val1 sha256:5664
 
-cat >expect_update <<EOF
-100644 blob 51d2738efb4ad8a1e40bed839ab8e116f0a15e47	foo
-EOF
+	val2 sha1:11742
+	val2 sha256:10625
 
-test_expect_success 'setup' '
-	echo 4827 > foo &&
+	hash1 sha1:51d2738463ea4ca66f8691c91e33ce64b7d41bb1
+	hash1 sha256:ae31dfff0af93b2c62b0098a039b38569c43b0a7e97b873000ca42d128f27350
+
+	hasht1 sha1:51d27384
+	hasht1 sha256:ae31dfff
+
+	hash2 sha1:51d2738efb4ad8a1e40bed839ab8e116f0a15e47
+	hash2 sha256:ae31dffada88a46fd5f53c7ed5aa25a7a8951f1d5e88456c317c8d5484d263e5
+
+	hasht2 sha1:51d2738e
+	hasht2 sha256:ae31dffa
+	EOF
+
+	cat >expect_initial <<-EOF &&
+	100644 blob $(test_oid hash1)	foo
+	EOF
+
+	cat >expect_update <<-EOF &&
+	100644 blob $(test_oid hash2)	foo
+	EOF
+
+	echo "$(test_oid val1)" > foo &&
 	git add foo &&
 	git commit -m "initial" &&
 	git cat-file -p HEAD: > actual &&
 	test_cmp expect_initial actual &&
-	echo 11742 > foo &&
+	echo "$(test_oid val2)" > foo &&
 	git commit -a -m "update" &&
 	git cat-file -p HEAD: > actual &&
 	test_cmp expect_update actual
 '
 
 cat >expect <<EOF
-index 51d27384..51d2738e 100644
+index $(test_oid hasht1)..$(test_oid hasht2) 100644
 EOF
 
 test_expect_success 'diff does not produce ambiguous index line' '
diff --git a/t/t4045-diff-relative.sh b/t/t4045-diff-relative.sh
index 36f8ed8a81..258808708e 100755
--- a/t/t4045-diff-relative.sh
+++ b/t/t4045-diff-relative.sh
@@ -70,7 +70,7 @@ check_raw () {
 	expect=$1
 	shift
 	cat >expected <<-EOF
-	:000000 100644 0000000000000000000000000000000000000000 $blob A	$expect
+	:000000 100644 $ZERO_OID $blob A	$expect
 	EOF
 	test_expect_success "--raw $*" "
 		git -C '$dir' diff --no-abbrev --raw $* HEAD^ >actual &&
diff --git a/t/t4048-diff-combined-binary.sh b/t/t4048-diff-combined-binary.sh
index 87a8949500..7f9ad9fa3d 100755
--- a/t/t4048-diff-combined-binary.sh
+++ b/t/t4048-diff-combined-binary.sh
@@ -9,24 +9,27 @@ test_expect_success 'setup binary merge conflict' '
 	git commit -m one &&
 	echo twoQ2 | q_to_nul >binary &&
 	git commit -a -m two &&
+	two=$(git rev-parse --short HEAD:binary) &&
 	git checkout -b branch-binary HEAD^ &&
 	echo threeQ3 | q_to_nul >binary &&
 	git commit -a -m three &&
+	three=$(git rev-parse --short HEAD:binary) &&
 	test_must_fail git merge master &&
 	echo resolvedQhooray | q_to_nul >binary &&
-	git commit -a -m resolved
+	git commit -a -m resolved &&
+	res=$(git rev-parse --short HEAD:binary)
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --git a/binary b/binary
-index 7ea6ded..9563691 100644
+index $three..$res 100644
 Binary files a/binary and b/binary differ
 resolved
 
 diff --git a/binary b/binary
-index 6197570..9563691 100644
+index $two..$res 100644
 Binary files a/binary and b/binary differ
 EOF
 test_expect_success 'diff -m indicates binary-ness' '
@@ -34,11 +37,11 @@ test_expect_success 'diff -m indicates binary-ness' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --combined binary
-index 7ea6ded,6197570..9563691
+index $three,$two..$res
 Binary files differ
 EOF
 test_expect_success 'diff -c indicates binary-ness' '
@@ -46,11 +49,11 @@ test_expect_success 'diff -c indicates binary-ness' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --cc binary
-index 7ea6ded,6197570..9563691
+index $three,$two..$res
 Binary files differ
 EOF
 test_expect_success 'diff --cc indicates binary-ness' '
@@ -62,23 +65,26 @@ test_expect_success 'setup non-binary with binary attribute' '
 	git checkout master &&
 	test_commit one text &&
 	test_commit two text &&
+	two=$(git rev-parse --short HEAD:text) &&
 	git checkout -b branch-text HEAD^ &&
 	test_commit three text &&
+	three=$(git rev-parse --short HEAD:text) &&
 	test_must_fail git merge master &&
 	test_commit resolved text &&
+	res=$(git rev-parse --short HEAD:text) &&
 	echo text -diff >.gitattributes
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --git a/text b/text
-index 2bdf67a..2ab19ae 100644
+index $three..$res 100644
 Binary files a/text and b/text differ
 resolved
 
 diff --git a/text b/text
-index f719efd..2ab19ae 100644
+index $two..$res 100644
 Binary files a/text and b/text differ
 EOF
 test_expect_success 'diff -m respects binary attribute' '
@@ -86,11 +92,11 @@ test_expect_success 'diff -m respects binary attribute' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --combined text
-index 2bdf67a,f719efd..2ab19ae
+index $three,$two..$res
 Binary files differ
 EOF
 test_expect_success 'diff -c respects binary attribute' '
@@ -98,11 +104,11 @@ test_expect_success 'diff -c respects binary attribute' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --cc text
-index 2bdf67a,f719efd..2ab19ae
+index $three,$two..$res
 Binary files differ
 EOF
 test_expect_success 'diff --cc respects binary attribute' '
@@ -115,11 +121,11 @@ test_expect_success 'setup textconv attribute' '
 	git config diff.upcase.textconv "tr a-z A-Z <"
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --git a/text b/text
-index 2bdf67a..2ab19ae 100644
+index $three..$res 100644
 --- a/text
 +++ b/text
 @@ -1 +1 @@
@@ -128,7 +134,7 @@ index 2bdf67a..2ab19ae 100644
 resolved
 
 diff --git a/text b/text
-index f719efd..2ab19ae 100644
+index $two..$res 100644
 --- a/text
 +++ b/text
 @@ -1 +1 @@
@@ -140,11 +146,11 @@ test_expect_success 'diff -m respects textconv attribute' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --combined text
-index 2bdf67a,f719efd..2ab19ae
+index $three,$two..$res
 --- a/text
 +++ b/text
 @@@ -1,1 -1,1 +1,1 @@@
@@ -157,11 +163,11 @@ test_expect_success 'diff -c respects textconv attribute' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 resolved
 
 diff --cc text
-index 2bdf67a,f719efd..2ab19ae
+index $three,$two..$res
 --- a/text
 +++ b/text
 @@@ -1,1 -1,1 +1,1 @@@
@@ -174,9 +180,9 @@ test_expect_success 'diff --cc respects textconv attribute' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 diff --combined text
-index 2bdf67a,f719efd..2ab19ae
+index $three,$two..$res
 --- a/text
 +++ b/text
 @@@ -1,1 -1,1 +1,1 @@@
@@ -190,9 +196,9 @@ test_expect_success 'diff-tree plumbing does not respect textconv' '
 	test_cmp expect actual
 '
 
-cat >expect <<'EOF'
+cat >expect <<EOF
 diff --cc text
-index 2bdf67a,f719efd..0000000
+index $three,$two..0000000
 --- a/text
 +++ b/text
 @@@ -1,1 -1,1 +1,5 @@@