Merge branch 'ar/unconfuse-three-dots'

Ancient part of codebase still shows dots after an abbreviated
object name just to show that it is not a full object name, but
these ellipses are confusing to people who newly discovered Git
who are used to seeing abbreviated object names and find them
confusing with the range syntax.

* ar/unconfuse-three-dots:
  t2020: test variations that matter
  t4013: test new output from diff --abbrev --raw
  diff: diff_aligned_abbrev: remove ellipsis after abbreviated SHA-1 value
  t4013: prepare for upcoming "diff --raw --abbrev" output format change
  checkout: describe_detached_head: remove ellipsis after committish
  print_sha1_ellipsis: introduce helper
  Documentation: user-manual: limit usage of ellipsis
  Documentation: revisions: fix typo: "three dot" ---> "three-dot" (in line with "two-dot").

18 files changed, 401 insertions, 9 deletions

diff --git a/t/t2020-checkout-detach.sh b/t/t2020-checkout-detach.sh
index fbb4ee9bb4..bb4f2e0c63 100755
--- a/t/t2020-checkout-detach.sh
+++ b/t/t2020-checkout-detach.sh
@@ -186,4 +186,127 @@ test_expect_success 'no advice given for explicit detached head state' '
 	test_cmp expect.no-advice actual
 '
 
+# Detached HEAD tests for GIT_PRINT_SHA1_ELLIPSIS (new format)
+test_expect_success 'describe_detached_head prints no SHA-1 ellipsis when not asked to' "
+
+	# The first detach operation is more chatty than the following ones.
+	cat >1st_detach <<-'EOF' &&
+	Note: checking out 'HEAD^'.
+
+	You are in 'detached HEAD' state. You can look around, make experimental
+	changes and commit them, and you can discard any commits you make in this
+	state without impacting any branches by performing another checkout.
+
+	If you want to create a new branch to retain commits you create, you may
+	do so (now or later) by using -b with the checkout command again. Example:
+
+	  git checkout -b <new-branch-name>
+
+	HEAD is now at 7c7cd714e262 three
+	EOF
+
+	# The remaining ones just show info about previous and current HEADs.
+	cat >2nd_detach <<-'EOF' &&
+	Previous HEAD position was 7c7cd714e262 three
+	HEAD is now at 139b20d8e6c5 two
+	EOF
+
+	cat >3rd_detach <<-'EOF' &&
+	Previous HEAD position was 139b20d8e6c5 two
+	HEAD is now at d79ce1670bdc one
+	EOF
+
+	reset &&
+	check_not_detached &&
+
+	# Various ways of *not* asking for ellipses
+
+	sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS="no" git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS= git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual &&
+
+	sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	# We only have four commits, but we can re-use them
+	reset &&
+	check_not_detached &&
+
+	# Make no mention of the env var at all
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS='nope' &&
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=nein &&
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual &&
+
+	true
+"
+
+# Detached HEAD tests for GIT_PRINT_SHA1_ELLIPSIS (old format)
+test_expect_success 'describe_detached_head does print SHA-1 ellipsis when asked to' "
+
+	# The first detach operation is more chatty than the following ones.
+	cat >1st_detach <<-'EOF' &&
+	Note: checking out 'HEAD^'.
+
+	You are in 'detached HEAD' state. You can look around, make experimental
+	changes and commit them, and you can discard any commits you make in this
+	state without impacting any branches by performing another checkout.
+
+	If you want to create a new branch to retain commits you create, you may
+	do so (now or later) by using -b with the checkout command again. Example:
+
+	  git checkout -b <new-branch-name>
+
+	HEAD is now at 7c7cd714e262... three
+	EOF
+
+	# The remaining ones just show info about previous and current HEADs.
+	cat >2nd_detach <<-'EOF' &&
+	Previous HEAD position was 7c7cd714e262... three
+	HEAD is now at 139b20d8e6c5... two
+	EOF
+
+	cat >3rd_detach <<-'EOF' &&
+	Previous HEAD position was 139b20d8e6c5... two
+	HEAD is now at d79ce1670bdc... one
+	EOF
+
+	reset &&
+	check_not_detached &&
+
+	# Various ways of asking for ellipses...
+	# The user can just use any kind of quoting (including none).
+
+	GIT_PRINT_SHA1_ELLIPSIS=yes git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=Yes git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=YES git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual &&
+
+	true
+"
+
 test_done
diff --git a/t/t3040-subprojects-basic.sh b/t/t3040-subprojects-basic.sh
index 0a4ff6d824..b81eb5fd6f 100755
--- a/t/t3040-subprojects-basic.sh
+++ b/t/t3040-subprojects-basic.sh
@@ -19,7 +19,7 @@ test_expect_success 'setup: create subprojects' '
 	git update-index --add sub1 &&
 	git add sub2 &&
 	git commit -q -m "subprojects added" &&
-	git diff-tree --abbrev=5 HEAD^ HEAD |cut -d" " -f-3,5- >current &&
+	GIT_PRINT_SHA1_ELLIPSIS="yes" git diff-tree --abbrev=5 HEAD^ HEAD |cut -d" " -f-3,5- >current &&
 	git branch save HEAD &&
 	cat >expected <<-\EOF &&
 	:000000 160000 00000... A	sub1
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index c515e3e53f..f10798b2df 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -118,20 +118,37 @@ test_expect_success setup '
 EOF
 
 V=$(git version | sed -e 's/^git version //' -e 's/\./\\./g')
-while read cmd
+while read magic cmd
 do
-	case "$cmd" in
-	'' | '#'*) continue ;;
+	case "$magic" in
+	'' | '#'*)
+		continue ;;
+	:*)
+		magic=${magic#:}
+		label="$magic-$cmd"
+		case "$magic" in
+		noellipses) ;;
+		*)
+			die "bug in t4103: unknown magic $magic" ;;
+		esac ;;
+	*)
+		cmd="$magic $cmd" magic=
+		label="$cmd" ;;
 	esac
-	test=$(echo "$cmd" | sed -e 's|[/ ][/ ]*|_|g')
+	test=$(echo "$label" | sed -e 's|[/ ][/ ]*|_|g')
 	pfx=$(printf "%04d" $test_count)
 	expect="$TEST_DIRECTORY/t4013/diff.$test"
 	actual="$pfx-diff.$test"
 
-	test_expect_success "git $cmd" '
+	test_expect_success "git $cmd # magic is ${magic:-"(not used)"}" '
 		{
-			echo "\$ git $cmd"
-			git $cmd |
+			echo "$ git $cmd"
+			case "$magic" in
+			"")
+				GIT_PRINT_SHA1_ELLIPSIS=yes git $cmd ;;
+			noellipses)
+				git $cmd ;;
+			esac |
 			sed -e "s/^\\(-*\\)$V\\(-*\\)\$/\\1g-i-t--v-e-r-s-i-o-n\2/" \
 			    -e "s/^\\(.*mixed; boundary=\"-*\\)$V\\(-*\\)\"\$/\\1g-i-t--v-e-r-s-i-o-n\2\"/"
 			echo "\$"
@@ -158,9 +175,12 @@ diff-tree -r --abbrev initial
 diff-tree -r --abbrev=4 initial
 diff-tree --root initial
 diff-tree --root --abbrev initial
+:noellipses diff-tree --root --abbrev initial
 diff-tree --root -r initial
 diff-tree --root -r --abbrev initial
+:noellipses diff-tree --root -r --abbrev initial
 diff-tree --root -r --abbrev=4 initial
+:noellipses diff-tree --root -r --abbrev=4 initial
 diff-tree -p initial
 diff-tree --root -p initial
 diff-tree --patch-with-stat initial
@@ -209,6 +229,7 @@ diff-tree -p master
 diff-tree -p -m master
 diff-tree -c master
 diff-tree -c --abbrev master
+:noellipses diff-tree -c --abbrev master
 diff-tree --cc master
 # stat only should show the diffstat with the first parent
 diff-tree -c --stat master
@@ -255,8 +276,10 @@ rev-list --parents HEAD
 rev-list --children HEAD
 
 whatchanged master
+:noellipses whatchanged master
 whatchanged -p master
 whatchanged --root master
+:noellipses whatchanged --root master
 whatchanged --root -p master
 whatchanged --patch-with-stat master
 whatchanged --root --patch-with-stat master
@@ -266,6 +289,7 @@ whatchanged --root -c --patch-with-stat --summary master
 # improved by Timo's patch
 whatchanged --root --cc --patch-with-stat --summary master
 whatchanged -SF master
+:noellipses whatchanged -SF master
 whatchanged -SF -p master
 
 log --patch-with-stat master -- dir/
@@ -284,6 +308,7 @@ show --stat side
 show --stat --summary side
 show --patch-with-stat side
 show --patch-with-raw side
+:noellipses show --patch-with-raw side
 show --patch-with-stat --summary side
 
 format-patch --stdout initial..side
@@ -311,8 +336,10 @@ diff -r --stat initial..side
 diff initial..side
 diff --patch-with-stat initial..side
 diff --patch-with-raw initial..side
+:noellipses diff --patch-with-raw initial..side
 diff --patch-with-stat -r initial..side
 diff --patch-with-raw -r initial..side
+:noellipses diff --patch-with-raw -r initial..side
 diff --name-status dir2 dir
 diff --no-index --name-status dir2 dir
 diff --no-index --name-status -- dir2 dir
@@ -325,10 +352,14 @@ diff --dirstat initial rearrange
 diff --dirstat-by-file initial rearrange
 # No-index --abbrev and --no-abbrev
 diff --raw initial
+:noellipses diff --raw initial
 diff --raw --abbrev=4 initial
+:noellipses diff --raw --abbrev=4 initial
 diff --raw --no-abbrev initial
 diff --no-index --raw dir2 dir
+:noellipses diff --no-index --raw dir2 dir
 diff --no-index --raw --abbrev=4 dir2 dir
+:noellipses diff --no-index --raw --abbrev=4 dir2 dir
 diff --no-index --raw --no-abbrev dir2 dir
 EOF
 
diff --git a/t/t4013/diff.noellipses-diff-tree_--root_--abbrev_initial b/t/t4013/diff.noellipses-diff-tree_--root_--abbrev_initial
new file mode 100644
index 0000000000..4bdad4072e
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff-tree_--root_--abbrev_initial
@@ -0,0 +1,6 @@
+$ git diff-tree --root --abbrev initial
+444ac553ac7612cc88969031b02b3767fb8a353a
+:000000 040000 0000000 da7a33f A	dir
+:000000 100644 0000000 01e79c3 A	file0
+:000000 100644 0000000 01e79c3 A	file2
+$
diff --git a/t/t4013/diff.noellipses-diff-tree_--root_-r_--abbrev=4_initial b/t/t4013/diff.noellipses-diff-tree_--root_-r_--abbrev=4_initial
new file mode 100644
index 0000000000..26fbfeb177
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff-tree_--root_-r_--abbrev=4_initial
@@ -0,0 +1,6 @@
+$ git diff-tree --root -r --abbrev=4 initial
+444ac553ac7612cc88969031b02b3767fb8a353a
+:000000 100644 0000 35d2 A	dir/sub
+:000000 100644 0000 01e7 A	file0
+:000000 100644 0000 01e7 A	file2
+$
diff --git a/t/t4013/diff.noellipses-diff-tree_--root_-r_--abbrev_initial b/t/t4013/diff.noellipses-diff-tree_--root_-r_--abbrev_initial
new file mode 100644
index 0000000000..2ac8561191
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff-tree_--root_-r_--abbrev_initial
@@ -0,0 +1,6 @@
+$ git diff-tree --root -r --abbrev initial
+444ac553ac7612cc88969031b02b3767fb8a353a
+:000000 100644 0000000 35d242b A	dir/sub
+:000000 100644 0000000 01e79c3 A	file0
+:000000 100644 0000000 01e79c3 A	file2
+$
diff --git a/t/t4013/diff.noellipses-diff-tree_-c_--abbrev_master b/t/t4013/diff.noellipses-diff-tree_-c_--abbrev_master
new file mode 100644
index 0000000000..bb80f013b3
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff-tree_-c_--abbrev_master
@@ -0,0 +1,5 @@
+$ git diff-tree -c --abbrev master
+59d314ad6f356dd08601a4cd5e530381da3e3c64
+::100644 100644 100644 cead32e 7289e35 992913c MM	dir/sub
+::100644 100644 100644 b414108 f4615da 10a8a9f MM	file0
+$
diff --git a/t/t4013/diff.noellipses-diff_--no-index_--raw_--abbrev=4_dir2_dir b/t/t4013/diff.noellipses-diff_--no-index_--raw_--abbrev=4_dir2_dir
new file mode 100644
index 0000000000..41b7baf0a5
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff_--no-index_--raw_--abbrev=4_dir2_dir
@@ -0,0 +1,3 @@
+$ git diff --no-index --raw --abbrev=4 dir2 dir
+:000000 100644 0000 0000 A	dir/sub
+$
diff --git a/t/t4013/diff.noellipses-diff_--no-index_--raw_dir2_dir b/t/t4013/diff.noellipses-diff_--no-index_--raw_dir2_dir
new file mode 100644
index 0000000000..0cf3a3efea
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff_--no-index_--raw_dir2_dir
@@ -0,0 +1,3 @@
+$ git diff --no-index --raw dir2 dir
+:000000 100644 0000000 0000000 A	dir/sub
+$
diff --git a/t/t4013/diff.noellipses-diff_--patch-with-raw_-r_initial..side b/t/t4013/diff.noellipses-diff_--patch-with-raw_-r_initial..side
new file mode 100644
index 0000000000..8d1f1e3721
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff_--patch-with-raw_-r_initial..side
@@ -0,0 +1,36 @@
+$ git diff --patch-with-raw -r initial..side
+:100644 100644 35d242b 7289e35 M	dir/sub
+:100644 100644 01e79c3 f4615da M	file0
+:000000 100644 0000000 7289e35 A	file3
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..7289e35 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++1
++2
+diff --git a/file0 b/file0
+index 01e79c3..f4615da 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++A
++B
++C
+diff --git a/file3 b/file3
+new file mode 100644
+index 0000000..7289e35
+--- /dev/null
++++ b/file3
+@@ -0,0 +1,4 @@
++A
++B
++1
++2
+$
diff --git a/t/t4013/diff.noellipses-diff_--patch-with-raw_initial..side b/t/t4013/diff.noellipses-diff_--patch-with-raw_initial..side
new file mode 100644
index 0000000000..50d8aee4f7
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff_--patch-with-raw_initial..side
@@ -0,0 +1,36 @@
+$ git diff --patch-with-raw initial..side
+:100644 100644 35d242b 7289e35 M	dir/sub
+:100644 100644 01e79c3 f4615da M	file0
+:000000 100644 0000000 7289e35 A	file3
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..7289e35 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++1
++2
+diff --git a/file0 b/file0
+index 01e79c3..f4615da 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++A
++B
++C
+diff --git a/file3 b/file3
+new file mode 100644
+index 0000000..7289e35
+--- /dev/null
++++ b/file3
+@@ -0,0 +1,4 @@
++A
++B
++1
++2
+$
diff --git a/t/t4013/diff.noellipses-diff_--raw_--abbrev=4_initial b/t/t4013/diff.noellipses-diff_--raw_--abbrev=4_initial
new file mode 100644
index 0000000000..8ae44d6c83
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff_--raw_--abbrev=4_initial
@@ -0,0 +1,6 @@
+$ git diff --raw --abbrev=4 initial
+:100644 100644 35d2 9929 M	dir/sub
+:100644 100644 01e7 10a8 M	file0
+:000000 100644 0000 b1e6 A	file1
+:100644 000000 01e7 0000 D	file2
+$
diff --git a/t/t4013/diff.noellipses-diff_--raw_initial b/t/t4013/diff.noellipses-diff_--raw_initial
new file mode 100644
index 0000000000..0175bfb281
--- /dev/null
+++ b/t/t4013/diff.noellipses-diff_--raw_initial
@@ -0,0 +1,6 @@
+$ git diff --raw initial
+:100644 100644 35d242b 992913c M	dir/sub
+:100644 100644 01e79c3 10a8a9f M	file0
+:000000 100644 0000000 b1e6722 A	file1
+:100644 000000 01e79c3 0000000 D	file2
+$
diff --git a/t/t4013/diff.noellipses-show_--patch-with-raw_side b/t/t4013/diff.noellipses-show_--patch-with-raw_side
new file mode 100644
index 0000000000..32fed3d576
--- /dev/null
+++ b/t/t4013/diff.noellipses-show_--patch-with-raw_side
@@ -0,0 +1,42 @@
+$ git show --patch-with-raw side
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+:100644 100644 35d242b 7289e35 M	dir/sub
+:100644 100644 01e79c3 f4615da M	file0
+:000000 100644 0000000 7289e35 A	file3
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..7289e35 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++1
++2
+diff --git a/file0 b/file0
+index 01e79c3..f4615da 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++A
++B
++C
+diff --git a/file3 b/file3
+new file mode 100644
+index 0000000..7289e35
+--- /dev/null
++++ b/file3
+@@ -0,0 +1,4 @@
++A
++B
++1
++2
+$
diff --git a/t/t4013/diff.noellipses-whatchanged_--root_master b/t/t4013/diff.noellipses-whatchanged_--root_master
new file mode 100644
index 0000000000..c2cfd4e729
--- /dev/null
+++ b/t/t4013/diff.noellipses-whatchanged_--root_master
@@ -0,0 +1,42 @@
+$ git whatchanged --root master
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+:100644 100644 35d242b 7289e35 M	dir/sub
+:100644 100644 01e79c3 f4615da M	file0
+:000000 100644 0000000 7289e35 A	file3
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+:100644 100644 8422d40 cead32e M	dir/sub
+:000000 100644 0000000 b1e6722 A	file1
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+:100644 100644 35d242b 8422d40 M	dir/sub
+:100644 100644 01e79c3 b414108 M	file0
+:100644 000000 01e79c3 0000000 D	file2
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+
+:000000 100644 0000000 35d242b A	dir/sub
+:000000 100644 0000000 01e79c3 A	file0
+:000000 100644 0000000 01e79c3 A	file2
+$
diff --git a/t/t4013/diff.noellipses-whatchanged_-SF_master b/t/t4013/diff.noellipses-whatchanged_-SF_master
new file mode 100644
index 0000000000..b36ce5886e
--- /dev/null
+++ b/t/t4013/diff.noellipses-whatchanged_-SF_master
@@ -0,0 +1,9 @@
+$ git whatchanged -SF master
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+:100644 100644 8422d40 cead32e M	dir/sub
+$
diff --git a/t/t4013/diff.noellipses-whatchanged_master b/t/t4013/diff.noellipses-whatchanged_master
new file mode 100644
index 0000000000..55e500f2ed
--- /dev/null
+++ b/t/t4013/diff.noellipses-whatchanged_master
@@ -0,0 +1,32 @@
+$ git whatchanged master
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+:100644 100644 35d242b 7289e35 M	dir/sub
+:100644 100644 01e79c3 f4615da M	file0
+:000000 100644 0000000 7289e35 A	file3
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+:100644 100644 8422d40 cead32e M	dir/sub
+:000000 100644 0000000 b1e6722 A	file1
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+:100644 100644 35d242b 8422d40 M	dir/sub
+:100644 100644 01e79c3 b414108 M	file0
+:100644 000000 01e79c3 0000000 D	file2
+$
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index d47560b634..e4d06accc4 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -876,7 +876,7 @@ test_expect_success 'L: verify internal tree sorting' '
 	EXPECT_END
 
 	git fast-import <input &&
-	git diff-tree --abbrev --raw L^ L >output &&
+	GIT_PRINT_SHA1_ELLIPSIS="yes" git diff-tree --abbrev --raw L^ L >output &&
 	test_cmp expect output
 '