Merge branch 'jk/diff-submodule-diff-inline'

The "git diff --submodule={short,log}" mechanism has been enhanced
to allow "--submodule=diff" to show the patch between the submodule
commits bound to the superproject.

* jk/diff-submodule-diff-inline:
  diff: teach diff to display submodule difference with an inline diff
  submodule: refactor show_submodule_summary with helper function
  submodule: convert show_submodule_summary to use struct object_id *
  allow do_submodule_path to work even if submodule isn't checked out
  diff: prepare for additional submodule formats
  graph: add support for --line-prefix on all graph-aware output
  diff.c: remove output_prefix_length field
  cache: add empty_tree_oid object and helper function

6 files changed, 1249 insertions, 0 deletions

diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 94ef5000e..566817e2e 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -306,6 +306,8 @@ diff --no-index --name-status dir2 dir
 diff --no-index --name-status -- dir2 dir
 diff --no-index dir dir3
 diff master master^ side
+# Can't use spaces...
+diff --line-prefix=abc master master^ side
 diff --dirstat master~1 master~2
 diff --dirstat initial rearrange
 diff --dirstat-by-file initial rearrange
@@ -325,6 +327,10 @@ test_expect_success 'diff --cached -- file on unborn branch' '
 	git diff --cached -- file0 >result &&
 	test_cmp "$TEST_DIRECTORY/t4013/diff.diff_--cached_--_file0" result
 '
+test_expect_success 'diff --line-prefix with spaces' '
+	git diff --line-prefix="| | | " --cached -- file0 >result &&
+	test_cmp "$TEST_DIRECTORY/t4013/diff.diff_--line-prefix_--cached_--_file0" result
+'
 
 test_expect_success 'diff-tree --stdin with log formatting' '
 	cat >expect <<-\EOF &&
diff --git a/t/t4013/diff.diff_--line-prefix=abc_master_master^_side b/t/t4013/diff.diff_--line-prefix=abc_master_master^_side
new file mode 100644
index 000000000..99f91e7f0
--- /dev/null
+++ b/t/t4013/diff.diff_--line-prefix=abc_master_master^_side
@@ -0,0 +1,29 @@
+$ git diff --line-prefix=abc master master^ side
+abcdiff --cc dir/sub
+abcindex cead32e,7289e35..992913c
+abc--- a/dir/sub
+abc+++ b/dir/sub
+abc@@@ -1,6 -1,4 +1,8 @@@
+abc  A
+abc  B
+abc +C
+abc +D
+abc +E
+abc +F
+abc+ 1
+abc+ 2
+abcdiff --cc file0
+abcindex b414108,f4615da..10a8a9f
+abc--- a/file0
+abc+++ b/file0
+abc@@@ -1,6 -1,6 +1,9 @@@
+abc  1
+abc  2
+abc  3
+abc +4
+abc +5
+abc +6
+abc+ A
+abc+ B
+abc+ C
+$
diff --git a/t/t4013/diff.diff_--line-prefix_--cached_--_file0 b/t/t4013/diff.diff_--line-prefix_--cached_--_file0
new file mode 100644
index 000000000..f41ba4d36
--- /dev/null
+++ b/t/t4013/diff.diff_--line-prefix_--cached_--_file0
@@ -0,0 +1,15 @@
+| | | diff --git a/file0 b/file0
+| | | new file mode 100644
+| | | index 0000000..10a8a9f
+| | | --- /dev/null
+| | | +++ b/file0
+| | | @@ -0,0 +1,9 @@
+| | | +1
+| | | +2
+| | | +3
+| | | +4
+| | | +5
+| | | +6
+| | | +A
+| | | +B
+| | | +C
diff --git a/t/t4059-diff-submodule-not-initialized.sh b/t/t4059-diff-submodule-not-initialized.sh
new file mode 100755
index 000000000..cd70fd519
--- /dev/null
+++ b/t/t4059-diff-submodule-not-initialized.sh
@@ -0,0 +1,127 @@
+#!/bin/sh
+#
+# Copyright (c) 2016 Jacob Keller, based on t4041 by Jens Lehmann
+#
+
+test_description='Test for submodule diff on non-checked out submodule
+
+This test tries to verify that add_submodule_odb works when the submodule was
+initialized previously but the checkout has since been removed.
+'
+
+. ./test-lib.sh
+
+# Tested non-UTF-8 encoding
+test_encoding="ISO8859-1"
+
+# String "added" in German (translated with Google Translate), encoded in UTF-8,
+# used in sample commit log messages in add_file() function below.
+added=$(printf "hinzugef\303\274gt")
+
+add_file () {
+	(
+		cd "$1" &&
+		shift &&
+		for name
+		do
+			echo "$name" >"$name" &&
+			git add "$name" &&
+			test_tick &&
+			# "git commit -m" would break MinGW, as Windows refuse to pass
+			# $test_encoding encoded parameter to git.
+			echo "Add $name ($added $name)" | iconv -f utf-8 -t $test_encoding |
+			git -c "i18n.commitEncoding=$test_encoding" commit -F -
+		done >/dev/null &&
+		git rev-parse --short --verify HEAD
+	)
+}
+
+commit_file () {
+	test_tick &&
+	git commit "$@" -m "Commit $*" >/dev/null
+}
+
+test_expect_success 'setup - submodules' '
+	test_create_repo sm2 &&
+	add_file . foo &&
+	add_file sm2 foo1 foo2 &&
+	smhead1=$(git -C sm2 rev-parse --short --verify HEAD)
+'
+
+test_expect_success 'setup - git submodule add' '
+	git submodule add ./sm2 sm1 &&
+	commit_file sm1 .gitmodules &&
+	git diff-tree -p --no-commit-id --submodule=log HEAD -- sm1 >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 0000000...$smhead1 (new submodule)
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'submodule directory removed' '
+	rm -rf sm1 &&
+	git diff-tree -p --no-commit-id --submodule=log HEAD -- sm1 >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 0000000...$smhead1 (new submodule)
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'setup - submodule multiple commits' '
+	git submodule update --checkout sm1 &&
+	smhead2=$(add_file sm1 foo3 foo4) &&
+	commit_file sm1 &&
+	git diff-tree -p --no-commit-id --submodule=log HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $smhead1..$smhead2:
+	  > Add foo4 ($added foo4)
+	  > Add foo3 ($added foo3)
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'submodule removed multiple commits' '
+	rm -rf sm1 &&
+	git diff-tree -p --no-commit-id --submodule=log HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $smhead1..$smhead2:
+	  > Add foo4 ($added foo4)
+	  > Add foo3 ($added foo3)
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'submodule not initialized in new clone' '
+	git clone . sm3 &&
+	git -C sm3 diff-tree -p --no-commit-id --submodule=log HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $smhead1...$smhead2 (not initialized)
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'setup submodule moved' '
+	git submodule update --checkout sm1 &&
+	git mv sm1 sm4 &&
+	commit_file sm4 &&
+	git diff-tree -p --no-commit-id --submodule=log HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm4 0000000...$smhead2 (new submodule)
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'submodule moved then removed' '
+	smhead3=$(add_file sm4 foo6 foo7) &&
+	commit_file sm4 &&
+	rm -rf sm4 &&
+	git diff-tree -p --no-commit-id --submodule=log HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm4 $smhead2..$smhead3:
+	  > Add foo7 ($added foo7)
+	  > Add foo6 ($added foo6)
+	EOF
+	test_cmp expected actual
+'
+
+test_done
diff --git a/t/t4060-diff-submodule-option-diff-format.sh b/t/t4060-diff-submodule-option-diff-format.sh
new file mode 100755
index 000000000..7e23b55ea
--- /dev/null
+++ b/t/t4060-diff-submodule-option-diff-format.sh
@@ -0,0 +1,749 @@
+#!/bin/sh
+#
+# Copyright (c) 2009 Jens Lehmann, based on t7401 by Ping Yin
+# Copyright (c) 2011 Alexey Shumkin (+ non-UTF-8 commit encoding tests)
+# Copyright (c) 2016 Jacob Keller (copy + convert to --submodule=diff)
+#
+
+test_description='Support for diff format verbose submodule difference in git diff
+
+This test tries to verify the sanity of --submodule=diff option of git diff.
+'
+
+. ./test-lib.sh
+
+# Tested non-UTF-8 encoding
+test_encoding="ISO8859-1"
+
+# String "added" in German (translated with Google Translate), encoded in UTF-8,
+# used in sample commit log messages in add_file() function below.
+added=$(printf "hinzugef\303\274gt")
+
+add_file () {
+	(
+		cd "$1" &&
+		shift &&
+		for name
+		do
+			echo "$name" >"$name" &&
+			git add "$name" &&
+			test_tick &&
+			# "git commit -m" would break MinGW, as Windows refuse to pass
+			# $test_encoding encoded parameter to git.
+			echo "Add $name ($added $name)" | iconv -f utf-8 -t $test_encoding |
+			git -c "i18n.commitEncoding=$test_encoding" commit -F -
+		done >/dev/null &&
+		git rev-parse --short --verify HEAD
+	)
+}
+
+commit_file () {
+	test_tick &&
+	git commit "$@" -m "Commit $*" >/dev/null
+}
+
+test_expect_success 'setup repository' '
+	test_create_repo sm1 &&
+	add_file . foo &&
+	head1=$(add_file sm1 foo1 foo2) &&
+	fullhead1=$(git -C sm1 rev-parse --verify HEAD)
+'
+
+test_expect_success 'added submodule' '
+	git add sm1 &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 0000000...$head1 (new submodule)
+	diff --git a/sm1/foo1 b/sm1/foo1
+	new file mode 100644
+	index 0000000..1715acd
+	--- /dev/null
+	+++ b/sm1/foo1
+	@@ -0,0 +1 @@
+	+foo1
+	diff --git a/sm1/foo2 b/sm1/foo2
+	new file mode 100644
+	index 0000000..54b060e
+	--- /dev/null
+	+++ b/sm1/foo2
+	@@ -0,0 +1 @@
+	+foo2
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'added submodule, set diff.submodule' '
+	test_config diff.submodule log &&
+	git add sm1 &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 0000000...$head1 (new submodule)
+	diff --git a/sm1/foo1 b/sm1/foo1
+	new file mode 100644
+	index 0000000..1715acd
+	--- /dev/null
+	+++ b/sm1/foo1
+	@@ -0,0 +1 @@
+	+foo1
+	diff --git a/sm1/foo2 b/sm1/foo2
+	new file mode 100644
+	index 0000000..54b060e
+	--- /dev/null
+	+++ b/sm1/foo2
+	@@ -0,0 +1 @@
+	+foo2
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success '--submodule=short overrides diff.submodule' '
+	test_config diff.submodule log &&
+	git add sm1 &&
+	git diff --submodule=short --cached >actual &&
+	cat >expected <<-EOF &&
+	diff --git a/sm1 b/sm1
+	new file mode 160000
+	index 0000000..$head1
+	--- /dev/null
+	+++ b/sm1
+	@@ -0,0 +1 @@
+	+Subproject commit $fullhead1
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'diff.submodule does not affect plumbing' '
+	test_config diff.submodule log &&
+	git diff-index -p HEAD >actual &&
+	cat >expected <<-EOF &&
+	diff --git a/sm1 b/sm1
+	new file mode 160000
+	index 0000000..$head1
+	--- /dev/null
+	+++ b/sm1
+	@@ -0,0 +1 @@
+	+Subproject commit $fullhead1
+	EOF
+	test_cmp expected actual
+'
+
+commit_file sm1 &&
+head2=$(add_file sm1 foo3)
+
+test_expect_success 'modified submodule(forward)' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head1..$head2:
+	diff --git a/sm1/foo3 b/sm1/foo3
+	new file mode 100644
+	index 0000000..c1ec6c6
+	--- /dev/null
+	+++ b/sm1/foo3
+	@@ -0,0 +1 @@
+	+foo3
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule(forward)' '
+	git diff --submodule=diff >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head1..$head2:
+	diff --git a/sm1/foo3 b/sm1/foo3
+	new file mode 100644
+	index 0000000..c1ec6c6
+	--- /dev/null
+	+++ b/sm1/foo3
+	@@ -0,0 +1 @@
+	+foo3
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule(forward) --submodule' '
+	git diff --submodule >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head1..$head2:
+	  > Add foo3 ($added foo3)
+	EOF
+	test_cmp expected actual
+'
+
+fullhead2=$(cd sm1; git rev-parse --verify HEAD)
+test_expect_success 'modified submodule(forward) --submodule=short' '
+	git diff --submodule=short >actual &&
+	cat >expected <<-EOF &&
+	diff --git a/sm1 b/sm1
+	index $head1..$head2 160000
+	--- a/sm1
+	+++ b/sm1
+	@@ -1 +1 @@
+	-Subproject commit $fullhead1
+	+Subproject commit $fullhead2
+	EOF
+	test_cmp expected actual
+'
+
+commit_file sm1 &&
+head3=$(
+	cd sm1 &&
+	git reset --hard HEAD~2 >/dev/null &&
+	git rev-parse --short --verify HEAD
+)
+
+test_expect_success 'modified submodule(backward)' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head2..$head3 (rewind):
+	diff --git a/sm1/foo2 b/sm1/foo2
+	deleted file mode 100644
+	index 54b060e..0000000
+	--- a/sm1/foo2
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo2
+	diff --git a/sm1/foo3 b/sm1/foo3
+	deleted file mode 100644
+	index c1ec6c6..0000000
+	--- a/sm1/foo3
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo3
+	EOF
+	test_cmp expected actual
+'
+
+head4=$(add_file sm1 foo4 foo5)
+test_expect_success 'modified submodule(backward and forward)' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head2...$head4:
+	diff --git a/sm1/foo2 b/sm1/foo2
+	deleted file mode 100644
+	index 54b060e..0000000
+	--- a/sm1/foo2
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo2
+	diff --git a/sm1/foo3 b/sm1/foo3
+	deleted file mode 100644
+	index c1ec6c6..0000000
+	--- a/sm1/foo3
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo3
+	diff --git a/sm1/foo4 b/sm1/foo4
+	new file mode 100644
+	index 0000000..a0016db
+	--- /dev/null
+	+++ b/sm1/foo4
+	@@ -0,0 +1 @@
+	+foo4
+	diff --git a/sm1/foo5 b/sm1/foo5
+	new file mode 100644
+	index 0000000..d6f2413
+	--- /dev/null
+	+++ b/sm1/foo5
+	@@ -0,0 +1 @@
+	+foo5
+	EOF
+	test_cmp expected actual
+'
+
+commit_file sm1 &&
+mv sm1 sm1-bak &&
+echo sm1 >sm1 &&
+head5=$(git hash-object sm1 | cut -c1-7) &&
+git add sm1 &&
+rm -f sm1 &&
+mv sm1-bak sm1
+
+test_expect_success 'typechanged submodule(submodule->blob), --cached' '
+	git diff --submodule=diff --cached >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head4...0000000 (submodule deleted)
+	diff --git a/sm1/foo1 b/sm1/foo1
+	deleted file mode 100644
+	index 1715acd..0000000
+	--- a/sm1/foo1
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo1
+	diff --git a/sm1/foo4 b/sm1/foo4
+	deleted file mode 100644
+	index a0016db..0000000
+	--- a/sm1/foo4
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo4
+	diff --git a/sm1/foo5 b/sm1/foo5
+	deleted file mode 100644
+	index d6f2413..0000000
+	--- a/sm1/foo5
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo5
+	diff --git a/sm1 b/sm1
+	new file mode 100644
+	index 0000000..9da5fb8
+	--- /dev/null
+	+++ b/sm1
+	@@ -0,0 +1 @@
+	+sm1
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'typechanged submodule(submodule->blob)' '
+	git diff --submodule=diff >actual &&
+	cat >expected <<-EOF &&
+	diff --git a/sm1 b/sm1
+	deleted file mode 100644
+	index 9da5fb8..0000000
+	--- a/sm1
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-sm1
+	Submodule sm1 0000000...$head4 (new submodule)
+	diff --git a/sm1/foo1 b/sm1/foo1
+	new file mode 100644
+	index 0000000..1715acd
+	--- /dev/null
+	+++ b/sm1/foo1
+	@@ -0,0 +1 @@
+	+foo1
+	diff --git a/sm1/foo4 b/sm1/foo4
+	new file mode 100644
+	index 0000000..a0016db
+	--- /dev/null
+	+++ b/sm1/foo4
+	@@ -0,0 +1 @@
+	+foo4
+	diff --git a/sm1/foo5 b/sm1/foo5
+	new file mode 100644
+	index 0000000..d6f2413
+	--- /dev/null
+	+++ b/sm1/foo5
+	@@ -0,0 +1 @@
+	+foo5
+	EOF
+	test_cmp expected actual
+'
+
+rm -rf sm1 &&
+git checkout-index sm1
+test_expect_success 'typechanged submodule(submodule->blob)' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head4...0000000 (submodule deleted)
+	diff --git a/sm1 b/sm1
+	new file mode 100644
+	index 0000000..9da5fb8
+	--- /dev/null
+	+++ b/sm1
+	@@ -0,0 +1 @@
+	+sm1
+	EOF
+	test_cmp expected actual
+'
+
+rm -f sm1 &&
+test_create_repo sm1 &&
+head6=$(add_file sm1 foo6 foo7)
+fullhead6=$(cd sm1; git rev-parse --verify HEAD)
+test_expect_success 'nonexistent commit' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head4...$head6 (commits not present)
+	EOF
+	test_cmp expected actual
+'
+
+commit_file
+test_expect_success 'typechanged submodule(blob->submodule)' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	diff --git a/sm1 b/sm1
+	deleted file mode 100644
+	index 9da5fb8..0000000
+	--- a/sm1
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-sm1
+	Submodule sm1 0000000...$head6 (new submodule)
+	diff --git a/sm1/foo6 b/sm1/foo6
+	new file mode 100644
+	index 0000000..462398b
+	--- /dev/null
+	+++ b/sm1/foo6
+	@@ -0,0 +1 @@
+	+foo6
+	diff --git a/sm1/foo7 b/sm1/foo7
+	new file mode 100644
+	index 0000000..6e9262c
+	--- /dev/null
+	+++ b/sm1/foo7
+	@@ -0,0 +1 @@
+	+foo7
+	EOF
+	test_cmp expected actual
+'
+
+commit_file sm1 &&
+test_expect_success 'submodule is up to date' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'submodule contains untracked content' '
+	echo new > sm1/new-file &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains untracked content
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'submodule contains untracked content (untracked ignored)' '
+	git diff-index -p --ignore-submodules=untracked --submodule=diff HEAD >actual &&
+	! test -s actual
+'
+
+test_expect_success 'submodule contains untracked content (dirty ignored)' '
+	git diff-index -p --ignore-submodules=dirty --submodule=diff HEAD >actual &&
+	! test -s actual
+'
+
+test_expect_success 'submodule contains untracked content (all ignored)' '
+	git diff-index -p --ignore-submodules=all --submodule=diff HEAD >actual &&
+	! test -s actual
+'
+
+test_expect_success 'submodule contains untracked and modified content' '
+	echo new > sm1/foo6 &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains untracked content
+	Submodule sm1 contains modified content
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+# NOT OK
+test_expect_success 'submodule contains untracked and modified content (untracked ignored)' '
+	echo new > sm1/foo6 &&
+	git diff-index -p --ignore-submodules=untracked --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains modified content
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'submodule contains untracked and modified content (dirty ignored)' '
+	echo new > sm1/foo6 &&
+	git diff-index -p --ignore-submodules=dirty --submodule=diff HEAD >actual &&
+	! test -s actual
+'
+
+test_expect_success 'submodule contains untracked and modified content (all ignored)' '
+	echo new > sm1/foo6 &&
+	git diff-index -p --ignore-submodules --submodule=diff HEAD >actual &&
+	! test -s actual
+'
+
+test_expect_success 'submodule contains modified content' '
+	rm -f sm1/new-file &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains modified content
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+(cd sm1; git commit -mchange foo6 >/dev/null) &&
+head8=$(cd sm1; git rev-parse --short --verify HEAD) &&
+test_expect_success 'submodule is modified' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9..$head8:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule contains untracked content' '
+	echo new > sm1/new-file &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains untracked content
+	Submodule sm1 17243c9..$head8:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule contains untracked content (untracked ignored)' '
+	git diff-index -p --ignore-submodules=untracked --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9..$head8:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule contains untracked content (dirty ignored)' '
+	git diff-index -p --ignore-submodules=dirty --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9..cfce562:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule contains untracked content (all ignored)' '
+	git diff-index -p --ignore-submodules=all --submodule=diff HEAD >actual &&
+	! test -s actual
+'
+
+test_expect_success 'modified submodule contains untracked and modified content' '
+	echo modification >> sm1/foo6 &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains untracked content
+	Submodule sm1 contains modified content
+	Submodule sm1 17243c9..cfce562:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..dfda541 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1,2 @@
+	-foo6
+	+new
+	+modification
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule contains untracked and modified content (untracked ignored)' '
+	echo modification >> sm1/foo6 &&
+	git diff-index -p --ignore-submodules=untracked --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains modified content
+	Submodule sm1 17243c9..cfce562:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..e20e2d9 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1,3 @@
+	-foo6
+	+new
+	+modification
+	+modification
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule contains untracked and modified content (dirty ignored)' '
+	echo modification >> sm1/foo6 &&
+	git diff-index -p --ignore-submodules=dirty --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9..cfce562:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..3e75765 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1 @@
+	-foo6
+	+new
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'modified submodule contains untracked and modified content (all ignored)' '
+	echo modification >> sm1/foo6 &&
+	git diff-index -p --ignore-submodules --submodule=diff HEAD >actual &&
+	! test -s actual
+'
+
+# NOT OK
+test_expect_success 'modified submodule contains modified content' '
+	rm -f sm1/new-file &&
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 contains modified content
+	Submodule sm1 17243c9..cfce562:
+	diff --git a/sm1/foo6 b/sm1/foo6
+	index 462398b..ac466ca 100644
+	--- a/sm1/foo6
+	+++ b/sm1/foo6
+	@@ -1 +1,5 @@
+	-foo6
+	+new
+	+modification
+	+modification
+	+modification
+	+modification
+	EOF
+	test_cmp expected actual
+'
+
+rm -rf sm1
+test_expect_success 'deleted submodule' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9...0000000 (submodule deleted)
+	EOF
+	test_cmp expected actual
+'
+
+test_create_repo sm2 &&
+head7=$(add_file sm2 foo8 foo9) &&
+git add sm2
+
+test_expect_success 'multiple submodules' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9...0000000 (submodule deleted)
+	Submodule sm2 0000000...a5a65c9 (new submodule)
+	diff --git a/sm2/foo8 b/sm2/foo8
+	new file mode 100644
+	index 0000000..db9916b
+	--- /dev/null
+	+++ b/sm2/foo8
+	@@ -0,0 +1 @@
+	+foo8
+	diff --git a/sm2/foo9 b/sm2/foo9
+	new file mode 100644
+	index 0000000..9c3b4f6
+	--- /dev/null
+	+++ b/sm2/foo9
+	@@ -0,0 +1 @@
+	+foo9
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'path filter' '
+	git diff-index -p --submodule=diff HEAD sm2 >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm2 0000000...a5a65c9 (new submodule)
+	diff --git a/sm2/foo8 b/sm2/foo8
+	new file mode 100644
+	index 0000000..db9916b
+	--- /dev/null
+	+++ b/sm2/foo8
+	@@ -0,0 +1 @@
+	+foo8
+	diff --git a/sm2/foo9 b/sm2/foo9
+	new file mode 100644
+	index 0000000..9c3b4f6
+	--- /dev/null
+	+++ b/sm2/foo9
+	@@ -0,0 +1 @@
+	+foo9
+	EOF
+	test_cmp expected actual
+'
+
+commit_file sm2
+test_expect_success 'given commit' '
+	git diff-index -p --submodule=diff HEAD^ >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9...0000000 (submodule deleted)
+	Submodule sm2 0000000...a5a65c9 (new submodule)
+	diff --git a/sm2/foo8 b/sm2/foo8
+	new file mode 100644
+	index 0000000..db9916b
+	--- /dev/null
+	+++ b/sm2/foo8
+	@@ -0,0 +1 @@
+	+foo8
+	diff --git a/sm2/foo9 b/sm2/foo9
+	new file mode 100644
+	index 0000000..9c3b4f6
+	--- /dev/null
+	+++ b/sm2/foo9
+	@@ -0,0 +1 @@
+	+foo9
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'setup .git file for sm2' '
+	(cd sm2 &&
+	 REAL="$(pwd)/../.real" &&
+	 mv .git "$REAL"
+	 echo "gitdir: $REAL" >.git)
+'
+
+test_expect_success 'diff --submodule=diff with .git file' '
+	git diff --submodule=diff HEAD^ >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 17243c9...0000000 (submodule deleted)
+	Submodule sm2 0000000...a5a65c9 (new submodule)
+	diff --git a/sm2/foo8 b/sm2/foo8
+	new file mode 100644
+	index 0000000..db9916b
+	--- /dev/null
+	+++ b/sm2/foo8
+	@@ -0,0 +1 @@
+	+foo8
+	diff --git a/sm2/foo9 b/sm2/foo9
+	new file mode 100644
+	index 0000000..9c3b4f6
+	--- /dev/null
+	+++ b/sm2/foo9
+	@@ -0,0 +1 @@
+	+foo9
+	EOF
+	test_cmp expected actual
+'
+
+test_done
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index e2db47c36..1ccbd5948 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -188,6 +188,16 @@ test_expect_success 'git log --no-walk=sorted <commits> sorts by commit time' '
 '
 
 cat > expect << EOF
+=== 804a787 sixth
+=== 394ef78 fifth
+=== 5d31159 fourth
+EOF
+test_expect_success 'git log --line-prefix="=== " --no-walk <commits> sorts by commit time' '
+	git log --line-prefix="=== " --no-walk --oneline 5d31159 804a787 394ef78 > actual &&
+	test_cmp expect actual
+'
+
+cat > expect << EOF
 5d31159 fourth
 804a787 sixth
 394ef78 fifth
@@ -284,6 +294,21 @@ test_expect_success 'simple log --graph' '
 	test_cmp expect actual
 '
 
+cat > expect <<EOF
+123 * Second
+123 * sixth
+123 * fifth
+123 * fourth
+123 * third
+123 * second
+123 * initial
+EOF
+
+test_expect_success 'simple log --graph --line-prefix="123 "' '
+	git log --graph --line-prefix="123 " --pretty=tformat:%s >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'set up merge history' '
 	git checkout -b side HEAD~4 &&
 	test_commit side-1 1 1 &&
@@ -313,6 +338,27 @@ test_expect_success 'log --graph with merge' '
 	test_cmp expect actual
 '
 
+cat > expect <<\EOF
+| | | *   Merge branch 'side'
+| | | |\
+| | | | * side-2
+| | | | * side-1
+| | | * | Second
+| | | * | sixth
+| | | * | fifth
+| | | * | fourth
+| | | |/
+| | | * third
+| | | * second
+| | | * initial
+EOF
+
+test_expect_success 'log --graph --line-prefix="| | | " with merge' '
+	git log --line-prefix="| | | " --graph --date-order --pretty=tformat:%s |
+		sed "s/ *\$//" >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'log --raw --graph -m with merge' '
 	git log --raw --graph --oneline -m master | head -n 500 >actual &&
 	grep "initial" actual
@@ -867,6 +913,283 @@ test_expect_success 'log --graph with diff and stats' '
 	test_i18ncmp expect actual.sanitized
 '
 
+cat >expect <<\EOF
+*** *   commit COMMIT_OBJECT_NAME
+*** |\  Merge: MERGE_PARENTS
+*** | | Author: A U Thor <author@example.com>
+*** | |
+*** | |     Merge HEADS DESCRIPTION
+*** | |
+*** | * commit COMMIT_OBJECT_NAME
+*** | | Author: A U Thor <author@example.com>
+*** | |
+*** | |     reach
+*** | | ---
+*** | |  reach.t | 1 +
+*** | |  1 file changed, 1 insertion(+)
+*** | |
+*** | | diff --git a/reach.t b/reach.t
+*** | | new file mode 100644
+*** | | index 0000000..10c9591
+*** | | --- /dev/null
+*** | | +++ b/reach.t
+*** | | @@ -0,0 +1 @@
+*** | | +reach
+*** | |
+*** |  \
+*** *-. \   commit COMMIT_OBJECT_NAME
+*** |\ \ \  Merge: MERGE_PARENTS
+*** | | | | Author: A U Thor <author@example.com>
+*** | | | |
+*** | | | |     Merge HEADS DESCRIPTION
+*** | | | |
+*** | | * | commit COMMIT_OBJECT_NAME
+*** | | |/  Author: A U Thor <author@example.com>
+*** | | |
+*** | | |       octopus-b
+*** | | |   ---
+*** | | |    octopus-b.t | 1 +
+*** | | |    1 file changed, 1 insertion(+)
+*** | | |
+*** | | |   diff --git a/octopus-b.t b/octopus-b.t
+*** | | |   new file mode 100644
+*** | | |   index 0000000..d5fcad0
+*** | | |   --- /dev/null
+*** | | |   +++ b/octopus-b.t
+*** | | |   @@ -0,0 +1 @@
+*** | | |   +octopus-b
+*** | | |
+*** | * | commit COMMIT_OBJECT_NAME
+*** | |/  Author: A U Thor <author@example.com>
+*** | |
+*** | |       octopus-a
+*** | |   ---
+*** | |    octopus-a.t | 1 +
+*** | |    1 file changed, 1 insertion(+)
+*** | |
+*** | |   diff --git a/octopus-a.t b/octopus-a.t
+*** | |   new file mode 100644
+*** | |   index 0000000..11ee015
+*** | |   --- /dev/null
+*** | |   +++ b/octopus-a.t
+*** | |   @@ -0,0 +1 @@
+*** | |   +octopus-a
+*** | |
+*** * | commit COMMIT_OBJECT_NAME
+*** |/  Author: A U Thor <author@example.com>
+*** |
+*** |       seventh
+*** |   ---
+*** |    seventh.t | 1 +
+*** |    1 file changed, 1 insertion(+)
+*** |
+*** |   diff --git a/seventh.t b/seventh.t
+*** |   new file mode 100644
+*** |   index 0000000..9744ffc
+*** |   --- /dev/null
+*** |   +++ b/seventh.t
+*** |   @@ -0,0 +1 @@
+*** |   +seventh
+*** |
+*** *   commit COMMIT_OBJECT_NAME
+*** |\  Merge: MERGE_PARENTS
+*** | | Author: A U Thor <author@example.com>
+*** | |
+*** | |     Merge branch 'tangle'
+*** | |
+*** | *   commit COMMIT_OBJECT_NAME
+*** | |\  Merge: MERGE_PARENTS
+*** | | | Author: A U Thor <author@example.com>
+*** | | |
+*** | | |     Merge branch 'side' (early part) into tangle
+*** | | |
+*** | * |   commit COMMIT_OBJECT_NAME
+*** | |\ \  Merge: MERGE_PARENTS
+*** | | | | Author: A U Thor <author@example.com>
+*** | | | |
+*** | | | |     Merge branch 'master' (early part) into tangle
+*** | | | |
+*** | * | | commit COMMIT_OBJECT_NAME
+*** | | | | Author: A U Thor <author@example.com>
+*** | | | |
+*** | | | |     tangle-a
+*** | | | | ---
+*** | | | |  tangle-a | 1 +
+*** | | | |  1 file changed, 1 insertion(+)
+*** | | | |
+*** | | | | diff --git a/tangle-a b/tangle-a
+*** | | | | new file mode 100644
+*** | | | | index 0000000..7898192
+*** | | | | --- /dev/null
+*** | | | | +++ b/tangle-a
+*** | | | | @@ -0,0 +1 @@
+*** | | | | +a
+*** | | | |
+*** * | | |   commit COMMIT_OBJECT_NAME
+*** |\ \ \ \  Merge: MERGE_PARENTS
+*** | | | | | Author: A U Thor <author@example.com>
+*** | | | | |
+*** | | | | |     Merge branch 'side'
+*** | | | | |
+*** | * | | | commit COMMIT_OBJECT_NAME
+*** | | |_|/  Author: A U Thor <author@example.com>
+*** | |/| |
+*** | | | |       side-2
+*** | | | |   ---
+*** | | | |    2 | 1 +
+*** | | | |    1 file changed, 1 insertion(+)
+*** | | | |
+*** | | | |   diff --git a/2 b/2
+*** | | | |   new file mode 100644
+*** | | | |   index 0000000..0cfbf08
+*** | | | |   --- /dev/null
+*** | | | |   +++ b/2
+*** | | | |   @@ -0,0 +1 @@
+*** | | | |   +2
+*** | | | |
+*** | * | | commit COMMIT_OBJECT_NAME
+*** | | | | Author: A U Thor <author@example.com>
+*** | | | |
+*** | | | |     side-1
+*** | | | | ---
+*** | | | |  1 | 1 +
+*** | | | |  1 file changed, 1 insertion(+)
+*** | | | |
+*** | | | | diff --git a/1 b/1
+*** | | | | new file mode 100644
+*** | | | | index 0000000..d00491f
+*** | | | | --- /dev/null
+*** | | | | +++ b/1
+*** | | | | @@ -0,0 +1 @@
+*** | | | | +1
+*** | | | |
+*** * | | | commit COMMIT_OBJECT_NAME
+*** | | | | Author: A U Thor <author@example.com>
+*** | | | |
+*** | | | |     Second
+*** | | | | ---
+*** | | | |  one | 1 +
+*** | | | |  1 file changed, 1 insertion(+)
+*** | | | |
+*** | | | | diff --git a/one b/one
+*** | | | | new file mode 100644
+*** | | | | index 0000000..9a33383
+*** | | | | --- /dev/null
+*** | | | | +++ b/one
+*** | | | | @@ -0,0 +1 @@
+*** | | | | +case
+*** | | | |
+*** * | | | commit COMMIT_OBJECT_NAME
+*** | |_|/  Author: A U Thor <author@example.com>
+*** |/| |
+*** | | |       sixth
+*** | | |   ---
+*** | | |    a/two | 1 -
+*** | | |    1 file changed, 1 deletion(-)
+*** | | |
+*** | | |   diff --git a/a/two b/a/two
+*** | | |   deleted file mode 100644
+*** | | |   index 9245af5..0000000
+*** | | |   --- a/a/two
+*** | | |   +++ /dev/null
+*** | | |   @@ -1 +0,0 @@
+*** | | |   -ni
+*** | | |
+*** * | | commit COMMIT_OBJECT_NAME
+*** | | | Author: A U Thor <author@example.com>
+*** | | |
+*** | | |     fifth
+*** | | | ---
+*** | | |  a/two | 1 +
+*** | | |  1 file changed, 1 insertion(+)
+*** | | |
+*** | | | diff --git a/a/two b/a/two
+*** | | | new file mode 100644
+*** | | | index 0000000..9245af5
+*** | | | --- /dev/null
+*** | | | +++ b/a/two
+*** | | | @@ -0,0 +1 @@
+*** | | | +ni
+*** | | |
+*** * | | commit COMMIT_OBJECT_NAME
+*** |/ /  Author: A U Thor <author@example.com>
+*** | |
+*** | |       fourth
+*** | |   ---
+*** | |    ein | 1 +
+*** | |    1 file changed, 1 insertion(+)
+*** | |
+*** | |   diff --git a/ein b/ein
+*** | |   new file mode 100644
+*** | |   index 0000000..9d7e69f
+*** | |   --- /dev/null
+*** | |   +++ b/ein
+*** | |   @@ -0,0 +1 @@
+*** | |   +ichi
+*** | |
+*** * | commit COMMIT_OBJECT_NAME
+*** |/  Author: A U Thor <author@example.com>
+*** |
+*** |       third
+*** |   ---
+*** |    ichi | 1 +
+*** |    one  | 1 -
+*** |    2 files changed, 1 insertion(+), 1 deletion(-)
+*** |
+*** |   diff --git a/ichi b/ichi
+*** |   new file mode 100644
+*** |   index 0000000..9d7e69f
+*** |   --- /dev/null
+*** |   +++ b/ichi
+*** |   @@ -0,0 +1 @@
+*** |   +ichi
+*** |   diff --git a/one b/one
+*** |   deleted file mode 100644
+*** |   index 9d7e69f..0000000
+*** |   --- a/one
+*** |   +++ /dev/null
+*** |   @@ -1 +0,0 @@
+*** |   -ichi
+*** |
+*** * commit COMMIT_OBJECT_NAME
+*** | Author: A U Thor <author@example.com>
+*** |
+*** |     second
+*** | ---
+*** |  one | 2 +-
+*** |  1 file changed, 1 insertion(+), 1 deletion(-)
+*** |
+*** | diff --git a/one b/one
+*** | index 5626abf..9d7e69f 100644
+*** | --- a/one
+*** | +++ b/one
+*** | @@ -1 +1 @@
+*** | -one
+*** | +ichi
+*** |
+*** * commit COMMIT_OBJECT_NAME
+***   Author: A U Thor <author@example.com>
+***
+***       initial
+***   ---
+***    one | 1 +
+***    1 file changed, 1 insertion(+)
+***
+***   diff --git a/one b/one
+***   new file mode 100644
+***   index 0000000..5626abf
+***   --- /dev/null
+***   +++ b/one
+***   @@ -0,0 +1 @@
+***   +one
+EOF
+
+test_expect_success 'log --line-prefix="*** " --graph with diff and stats' '
+	git log --line-prefix="*** " --no-renames --graph --pretty=short --stat -p >actual &&
+	sanitize_output >actual.sanitized <actual &&
+	test_i18ncmp expect actual.sanitized
+'
+
 test_expect_success 'dotdot is a parent directory' '
 	mkdir -p a/b &&
 	( echo sixth && echo fifth ) >expect &&