Squashed 'third_party/git/' content from commit cb71568594

git-subtree-dir: third_party/git
git-subtree-split: cb715685942260375e1eb8153b0768a376e4ece7

1 files changed, 899 insertions, 0 deletions

diff --git a/t/t6022-merge-rename.sh b/t/t6022-merge-rename.sh
new file mode 100755
index 000000000000..53cc9b2ffbdb
--- /dev/null
+++ b/t/t6022-merge-rename.sh
@@ -0,0 +1,899 @@
+#!/bin/sh
+
+test_description='Merge-recursive merging renames'
+. ./test-lib.sh
+
+modify () {
+	sed -e "$1" <"$2" >"$2.x" &&
+	mv "$2.x" "$2"
+}
+
+test_expect_success setup \
+'
+cat >A <<\EOF &&
+a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+b bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+c cccccccccccccccccccccccccccccccccccccccccccccccc
+d dddddddddddddddddddddddddddddddddddddddddddddddd
+e eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
+f ffffffffffffffffffffffffffffffffffffffffffffffff
+g gggggggggggggggggggggggggggggggggggggggggggggggg
+h hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
+i iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
+j jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
+k kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
+l llllllllllllllllllllllllllllllllllllllllllllllll
+m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
+n nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
+o oooooooooooooooooooooooooooooooooooooooooooooooo
+EOF
+
+cat >M <<\EOF &&
+A AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+B BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
+C CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
+D DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
+E EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
+F FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
+G GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
+H HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
+I IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
+J JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ
+K KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
+L LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL
+M MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
+N NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
+O OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
+EOF
+
+git add A M &&
+git commit -m "initial has A and M" &&
+git branch white &&
+git branch red &&
+git branch blue &&
+git branch yellow &&
+git branch change &&
+git branch change+rename &&
+
+sed -e "/^g /s/.*/g : master changes a line/" <A >A+ &&
+mv A+ A &&
+git commit -a -m "master updates A" &&
+
+git checkout yellow &&
+rm -f M &&
+git commit -a -m "yellow removes M" &&
+
+git checkout white &&
+sed -e "/^g /s/.*/g : white changes a line/" <A >B &&
+sed -e "/^G /s/.*/G : colored branch changes a line/" <M >N &&
+rm -f A M &&
+git update-index --add --remove A B M N &&
+git commit -m "white renames A->B, M->N" &&
+
+git checkout red &&
+sed -e "/^g /s/.*/g : red changes a line/" <A >B &&
+sed -e "/^G /s/.*/G : colored branch changes a line/" <M >N &&
+rm -f A M &&
+git update-index --add --remove A B M N &&
+git commit -m "red renames A->B, M->N" &&
+
+git checkout blue &&
+sed -e "/^g /s/.*/g : blue changes a line/" <A >C &&
+sed -e "/^G /s/.*/G : colored branch changes a line/" <M >N &&
+rm -f A M &&
+git update-index --add --remove A C M N &&
+git commit -m "blue renames A->C, M->N" &&
+
+git checkout change &&
+sed -e "/^g /s/.*/g : changed line/" <A >A+ &&
+mv A+ A &&
+git commit -q -a -m "changed" &&
+
+git checkout change+rename &&
+sed -e "/^g /s/.*/g : changed line/" <A >B &&
+rm A &&
+git update-index --add B &&
+git commit -q -a -m "changed and renamed" &&
+
+git checkout master'
+
+test_expect_success 'pull renaming branch into unrenaming one' \
+'
+	git show-branch &&
+	test_expect_code 1 git pull . white &&
+	git ls-files -s &&
+	git ls-files -u B >b.stages &&
+	test_line_count = 3 b.stages &&
+	git ls-files -s N >n.stages &&
+	test_line_count = 1 n.stages &&
+	sed -ne "/^g/{
+	p
+	q
+	}" B | grep master &&
+	git diff --exit-code white N
+'
+
+test_expect_success 'pull renaming branch into another renaming one' \
+'
+	rm -f B &&
+	git reset --hard &&
+	git checkout red &&
+	test_expect_code 1 git pull . white &&
+	git ls-files -u B >b.stages &&
+	test_line_count = 3 b.stages &&
+	git ls-files -s N >n.stages &&
+	test_line_count = 1 n.stages &&
+	sed -ne "/^g/{
+	p
+	q
+	}" B | grep red &&
+	git diff --exit-code white N
+'
+
+test_expect_success 'pull unrenaming branch into renaming one' \
+'
+	git reset --hard &&
+	git show-branch &&
+	test_expect_code 1 git pull . master &&
+	git ls-files -u B >b.stages &&
+	test_line_count = 3 b.stages &&
+	git ls-files -s N >n.stages &&
+	test_line_count = 1 n.stages &&
+	sed -ne "/^g/{
+	p
+	q
+	}" B | grep red &&
+	git diff --exit-code white N
+'
+
+test_expect_success 'pull conflicting renames' \
+'
+	git reset --hard &&
+	git show-branch &&
+	test_expect_code 1 git pull . blue &&
+	git ls-files -u A >a.stages &&
+	test_line_count = 1 a.stages &&
+	git ls-files -u B >b.stages &&
+	test_line_count = 1 b.stages &&
+	git ls-files -u C >c.stages &&
+	test_line_count = 1 c.stages &&
+	git ls-files -s N >n.stages &&
+	test_line_count = 1 n.stages &&
+	sed -ne "/^g/{
+	p
+	q
+	}" B | grep red &&
+	git diff --exit-code white N
+'
+
+test_expect_success 'interference with untracked working tree file' '
+	git reset --hard &&
+	git show-branch &&
+	echo >A this file should not matter &&
+	test_expect_code 1 git pull . white &&
+	test_path_is_file A
+'
+
+test_expect_success 'interference with untracked working tree file' '
+	git reset --hard &&
+	git checkout white &&
+	git show-branch &&
+	rm -f A &&
+	echo >A this file should not matter &&
+	test_expect_code 1 git pull . red &&
+	test_path_is_file A
+'
+
+test_expect_success 'interference with untracked working tree file' '
+	git reset --hard &&
+	rm -f A M &&
+	git checkout -f master &&
+	git tag -f anchor &&
+	git show-branch &&
+	git pull . yellow &&
+	test_path_is_missing M &&
+	git reset --hard anchor
+'
+
+test_expect_success 'updated working tree file should prevent the merge' '
+	git reset --hard &&
+	rm -f A M &&
+	git checkout -f master &&
+	git tag -f anchor &&
+	git show-branch &&
+	echo >>M one line addition &&
+	cat M >M.saved &&
+	test_expect_code 128 git pull . yellow &&
+	test_cmp M M.saved &&
+	rm -f M.saved
+'
+
+test_expect_success 'updated working tree file should prevent the merge' '
+	git reset --hard &&
+	rm -f A M &&
+	git checkout -f master &&
+	git tag -f anchor &&
+	git show-branch &&
+	echo >>M one line addition &&
+	cat M >M.saved &&
+	git update-index M &&
+	test_expect_code 128 git pull . yellow &&
+	test_cmp M M.saved &&
+	rm -f M.saved
+'
+
+test_expect_success 'interference with untracked working tree file' '
+	git reset --hard &&
+	rm -f A M &&
+	git checkout -f yellow &&
+	git tag -f anchor &&
+	git show-branch &&
+	echo >M this file should not matter &&
+	git pull . master &&
+	test_path_is_file M &&
+	! {
+		git ls-files -s |
+		grep M
+	} &&
+	git reset --hard anchor
+'
+
+test_expect_success 'merge of identical changes in a renamed file' '
+	rm -f A M N &&
+	git reset --hard &&
+	git checkout change+rename &&
+	GIT_MERGE_VERBOSITY=3 git merge change >out &&
+	test_i18ngrep "^Skipped B" out &&
+	git reset --hard HEAD^ &&
+	git checkout change &&
+	GIT_MERGE_VERBOSITY=3 git merge change+rename >out &&
+	test_i18ngrep ! "^Skipped B" out
+'
+
+test_expect_success 'setup for rename + d/f conflicts' '
+	git reset --hard &&
+	git checkout --orphan dir-in-way &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	mkdir sub &&
+	mkdir dir &&
+	printf "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n" >sub/file &&
+	echo foo >dir/file-in-the-way &&
+	git add -A &&
+	git commit -m "Common commit" &&
+
+	echo 11 >>sub/file &&
+	echo more >>dir/file-in-the-way &&
+	git add -u &&
+	git commit -m "Commit to merge, with dir in the way" &&
+
+	git checkout -b dir-not-in-way &&
+	git reset --soft HEAD^ &&
+	git rm -rf dir &&
+	git commit -m "Commit to merge, with dir removed" -- dir sub/file &&
+
+	git checkout -b renamed-file-has-no-conflicts dir-in-way~1 &&
+	git rm -rf dir &&
+	git rm sub/file &&
+	printf "1\n2\n3\n4\n5555\n6\n7\n8\n9\n10\n" >dir &&
+	git add dir &&
+	git commit -m "Independent change" &&
+
+	git checkout -b renamed-file-has-conflicts dir-in-way~1 &&
+	git rm -rf dir &&
+	git mv sub/file dir &&
+	echo 12 >>dir &&
+	git add dir &&
+	git commit -m "Conflicting change"
+'
+
+printf "1\n2\n3\n4\n5555\n6\n7\n8\n9\n10\n11\n" >expected
+
+test_expect_success 'Rename+D/F conflict; renamed file merges + dir not in way' '
+	git reset --hard &&
+	git checkout -q renamed-file-has-no-conflicts^0 &&
+	git merge --strategy=recursive dir-not-in-way &&
+	git diff --quiet &&
+	test -f dir &&
+	test_cmp expected dir
+'
+
+test_expect_success 'Rename+D/F conflict; renamed file merges but dir in way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q renamed-file-has-no-conflicts^0 &&
+	test_must_fail git merge --strategy=recursive dir-in-way >output &&
+
+	test_i18ngrep "CONFLICT (modify/delete): dir/file-in-the-way" output &&
+	test_i18ngrep "Auto-merging dir" output &&
+	test_i18ngrep "Adding as dir~HEAD instead" output &&
+
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~HEAD &&
+	test_cmp expected dir~HEAD
+'
+
+test_expect_success 'Same as previous, but merged other way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q dir-in-way^0 &&
+	test_must_fail git merge --strategy=recursive renamed-file-has-no-conflicts >output 2>errors &&
+
+	! grep "error: refusing to lose untracked file at" errors &&
+	test_i18ngrep "CONFLICT (modify/delete): dir/file-in-the-way" output &&
+	test_i18ngrep "Auto-merging dir" output &&
+	test_i18ngrep "Adding as dir~renamed-file-has-no-conflicts instead" output &&
+
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~renamed-file-has-no-conflicts &&
+	test_cmp expected dir~renamed-file-has-no-conflicts
+'
+
+cat >expected <<\EOF &&
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+<<<<<<< HEAD:dir
+12
+=======
+11
+>>>>>>> dir-not-in-way:sub/file
+EOF
+
+test_expect_success 'Rename+D/F conflict; renamed file cannot merge, dir not in way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q renamed-file-has-conflicts^0 &&
+	test_must_fail git merge --strategy=recursive dir-not-in-way &&
+
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 3 -eq "$(git ls-files -u dir | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir &&
+	test_cmp expected dir
+'
+
+test_expect_success 'Rename+D/F conflict; renamed file cannot merge and dir in the way' '
+	modify s/dir-not-in-way/dir-in-way/ expected &&
+
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q renamed-file-has-conflicts^0 &&
+	test_must_fail git merge --strategy=recursive dir-in-way &&
+
+	test 5 -eq "$(git ls-files -u | wc -l)" &&
+	test 3 -eq "$(git ls-files -u dir | grep -v file-in-the-way | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~HEAD &&
+	test_cmp expected dir~HEAD
+'
+
+cat >expected <<\EOF &&
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+<<<<<<< HEAD:sub/file
+11
+=======
+12
+>>>>>>> renamed-file-has-conflicts:dir
+EOF
+
+test_expect_success 'Same as previous, but merged other way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q dir-in-way^0 &&
+	test_must_fail git merge --strategy=recursive renamed-file-has-conflicts &&
+
+	test 5 -eq "$(git ls-files -u | wc -l)" &&
+	test 3 -eq "$(git ls-files -u dir | grep -v file-in-the-way | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~renamed-file-has-conflicts &&
+	test_cmp expected dir~renamed-file-has-conflicts
+'
+
+test_expect_success 'setup both rename source and destination involved in D/F conflict' '
+	git reset --hard &&
+	git checkout --orphan rename-dest &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	mkdir one &&
+	echo stuff >one/file &&
+	git add -A &&
+	git commit -m "Common commit" &&
+
+	git mv one/file destdir &&
+	git commit -m "Renamed to destdir" &&
+
+	git checkout -b source-conflict HEAD~1 &&
+	git rm -rf one &&
+	mkdir destdir &&
+	touch one destdir/foo &&
+	git add -A &&
+	git commit -m "Conflicts in the way"
+'
+
+test_expect_success 'both rename source and destination involved in D/F conflict' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q rename-dest^0 &&
+	test_must_fail git merge --strategy=recursive source-conflict &&
+
+	test 1 -eq "$(git ls-files -u | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+
+	test -f destdir/foo &&
+	test -f one &&
+	test -f destdir~HEAD &&
+	test "stuff" = "$(cat destdir~HEAD)"
+'
+
+test_expect_success 'setup pair rename to parent of other (D/F conflicts)' '
+	git reset --hard &&
+	git checkout --orphan rename-two &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	mkdir one &&
+	mkdir two &&
+	echo stuff >one/file &&
+	echo other >two/file &&
+	git add -A &&
+	git commit -m "Common commit" &&
+
+	git rm -rf one &&
+	git mv two/file one &&
+	git commit -m "Rename two/file -> one" &&
+
+	git checkout -b rename-one HEAD~1 &&
+	git rm -rf two &&
+	git mv one/file two &&
+	rm -r one &&
+	git commit -m "Rename one/file -> two"
+'
+
+test_expect_success 'pair rename to parent of other (D/F conflicts) w/ untracked dir' '
+	git checkout -q rename-one^0 &&
+	mkdir one &&
+	test_must_fail git merge --strategy=recursive rename-two &&
+
+	test 2 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+
+	test 4 -eq $(find . | grep -v .git | wc -l) &&
+
+	test -d one &&
+	test -f one~rename-two &&
+	test -f two &&
+	test "other" = $(cat one~rename-two) &&
+	test "stuff" = $(cat two)
+'
+
+test_expect_success 'pair rename to parent of other (D/F conflicts) w/ clean start' '
+	git reset --hard &&
+	git clean -fdqx &&
+	test_must_fail git merge --strategy=recursive rename-two &&
+
+	test 2 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+
+	test 3 -eq $(find . | grep -v .git | wc -l) &&
+
+	test -f one &&
+	test -f two &&
+	test "other" = $(cat one) &&
+	test "stuff" = $(cat two)
+'
+
+test_expect_success 'setup rename of one file to two, with directories in the way' '
+	git reset --hard &&
+	git checkout --orphan first-rename &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	echo stuff >original &&
+	git add -A &&
+	git commit -m "Common commit" &&
+
+	mkdir two &&
+	>two/file &&
+	git add two/file &&
+	git mv original one &&
+	git commit -m "Put two/file in the way, rename to one" &&
+
+	git checkout -b second-rename HEAD~1 &&
+	mkdir one &&
+	>one/file &&
+	git add one/file &&
+	git mv original two &&
+	git commit -m "Put one/file in the way, rename to two"
+'
+
+test_expect_success 'check handling of differently renamed file with D/F conflicts' '
+	git checkout -q first-rename^0 &&
+	test_must_fail git merge --strategy=recursive second-rename &&
+
+	test 5 -eq "$(git ls-files -s | wc -l)" &&
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+	test 1 -eq "$(git ls-files -u original | wc -l)" &&
+	test 2 -eq "$(git ls-files -o | wc -l)" &&
+
+	test -f one/file &&
+	test -f two/file &&
+	test -f one~HEAD &&
+	test -f two~second-rename &&
+	! test -f original
+'
+
+test_expect_success 'setup rename one file to two; directories moving out of the way' '
+	git reset --hard &&
+	git checkout --orphan first-rename-redo &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	echo stuff >original &&
+	mkdir one two &&
+	touch one/file two/file &&
+	git add -A &&
+	git commit -m "Common commit" &&
+
+	git rm -rf one &&
+	git mv original one &&
+	git commit -m "Rename to one" &&
+
+	git checkout -b second-rename-redo HEAD~1 &&
+	git rm -rf two &&
+	git mv original two &&
+	git commit -m "Rename to two"
+'
+
+test_expect_success 'check handling of differently renamed file with D/F conflicts' '
+	git checkout -q first-rename-redo^0 &&
+	test_must_fail git merge --strategy=recursive second-rename-redo &&
+
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+	test 1 -eq "$(git ls-files -u original | wc -l)" &&
+	test 0 -eq "$(git ls-files -o | wc -l)" &&
+
+	test -f one &&
+	test -f two &&
+	! test -f original
+'
+
+test_expect_success 'setup avoid unnecessary update, normal rename' '
+	git reset --hard &&
+	git checkout --orphan avoid-unnecessary-update-1 &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	printf "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n" >original &&
+	git add -A &&
+	git commit -m "Common commit" &&
+
+	git mv original rename &&
+	echo 11 >>rename &&
+	git add -u &&
+	git commit -m "Renamed and modified" &&
+
+	git checkout -b merge-branch-1 HEAD~1 &&
+	echo "random content" >random-file &&
+	git add -A &&
+	git commit -m "Random, unrelated changes"
+'
+
+test_expect_success 'avoid unnecessary update, normal rename' '
+	git checkout -q avoid-unnecessary-update-1^0 &&
+	test-tool chmtime --get =1000000000 rename >expect &&
+	git merge merge-branch-1 &&
+	test-tool chmtime --get rename >actual &&
+	test_cmp expect actual # "rename" should have stayed intact
+'
+
+test_expect_success 'setup to test avoiding unnecessary update, with D/F conflict' '
+	git reset --hard &&
+	git checkout --orphan avoid-unnecessary-update-2 &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	mkdir df &&
+	printf "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n" >df/file &&
+	git add -A &&
+	git commit -m "Common commit" &&
+
+	git mv df/file temp &&
+	rm -rf df &&
+	git mv temp df &&
+	echo 11 >>df &&
+	git add -u &&
+	git commit -m "Renamed and modified" &&
+
+	git checkout -b merge-branch-2 HEAD~1 &&
+	>unrelated-change &&
+	git add unrelated-change &&
+	git commit -m "Only unrelated changes"
+'
+
+test_expect_success 'avoid unnecessary update, with D/F conflict' '
+	git checkout -q avoid-unnecessary-update-2^0 &&
+	test-tool chmtime --get =1000000000 df >expect &&
+	git merge merge-branch-2 &&
+	test-tool chmtime --get df >actual &&
+	test_cmp expect actual # "df" should have stayed intact
+'
+
+test_expect_success 'setup avoid unnecessary update, dir->(file,nothing)' '
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	>irrelevant &&
+	mkdir df &&
+	>df/file &&
+	git add -A &&
+	git commit -mA &&
+
+	git checkout -b side &&
+	git rm -rf df &&
+	git commit -mB &&
+
+	git checkout master &&
+	git rm -rf df &&
+	echo bla >df &&
+	git add -A &&
+	git commit -m "Add a newfile"
+'
+
+test_expect_success 'avoid unnecessary update, dir->(file,nothing)' '
+	git checkout -q master^0 &&
+	test-tool chmtime --get =1000000000 df >expect &&
+	git merge side &&
+	test-tool chmtime --get df >actual &&
+	test_cmp expect actual # "df" should have stayed intact
+'
+
+test_expect_success 'setup avoid unnecessary update, modify/delete' '
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	>irrelevant &&
+	>file &&
+	git add -A &&
+	git commit -mA &&
+
+	git checkout -b side &&
+	git rm -f file &&
+	git commit -m "Delete file" &&
+
+	git checkout master &&
+	echo bla >file &&
+	git add -A &&
+	git commit -m "Modify file"
+'
+
+test_expect_success 'avoid unnecessary update, modify/delete' '
+	git checkout -q master^0 &&
+	test-tool chmtime --get =1000000000 file >expect &&
+	test_must_fail git merge side &&
+	test-tool chmtime --get file >actual &&
+	test_cmp expect actual # "file" should have stayed intact
+'
+
+test_expect_success 'setup avoid unnecessary update, rename/add-dest' '
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	printf "1\n2\n3\n4\n5\n6\n7\n8\n" >file &&
+	git add -A &&
+	git commit -mA &&
+
+	git checkout -b side &&
+	cp file newfile &&
+	git add -A &&
+	git commit -m "Add file copy" &&
+
+	git checkout master &&
+	git mv file newfile &&
+	git commit -m "Rename file"
+'
+
+test_expect_success 'avoid unnecessary update, rename/add-dest' '
+	git checkout -q master^0 &&
+	test-tool chmtime --get =1000000000 newfile >expect &&
+	git merge side &&
+	test-tool chmtime --get newfile >actual &&
+	test_cmp expect actual # "file" should have stayed intact
+'
+
+test_expect_success 'setup merge of rename + small change' '
+	git reset --hard &&
+	git checkout --orphan rename-plus-small-change &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	echo ORIGINAL >file &&
+	git add file &&
+
+	test_tick &&
+	git commit -m Initial &&
+	git checkout -b rename_branch &&
+	git mv file renamed_file &&
+	git commit -m Rename &&
+	git checkout rename-plus-small-change &&
+	echo NEW-VERSION >file &&
+	git commit -a -m Reformat
+'
+
+test_expect_success 'merge rename + small change' '
+	git merge rename_branch &&
+
+	test 1 -eq $(git ls-files -s | wc -l) &&
+	test 0 -eq $(git ls-files -o | wc -l) &&
+	test $(git rev-parse HEAD:renamed_file) = $(git rev-parse HEAD~1:file)
+'
+
+test_expect_success 'setup for use of extended merge markers' '
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	printf "1\n2\n3\n4\n5\n6\n7\n8\n" >original_file &&
+	git add original_file &&
+	git commit -mA &&
+
+	git checkout -b rename &&
+	echo 9 >>original_file &&
+	git add original_file &&
+	git mv original_file renamed_file &&
+	git commit -mB &&
+
+	git checkout master &&
+	echo 8.5 >>original_file &&
+	git add original_file &&
+	git commit -mC
+'
+
+cat >expected <<\EOF &&
+1
+2
+3
+4
+5
+6
+7
+8
+<<<<<<< HEAD:renamed_file
+9
+=======
+8.5
+>>>>>>> master^0:original_file
+EOF
+
+test_expect_success 'merge master into rename has correct extended markers' '
+	git checkout rename^0 &&
+	test_must_fail git merge -s recursive master^0 &&
+	test_cmp expected renamed_file
+'
+
+cat >expected <<\EOF &&
+1
+2
+3
+4
+5
+6
+7
+8
+<<<<<<< HEAD:original_file
+8.5
+=======
+9
+>>>>>>> rename^0:renamed_file
+EOF
+
+test_expect_success 'merge rename into master has correct extended markers' '
+	git reset --hard &&
+	git checkout master^0 &&
+	test_must_fail git merge -s recursive rename^0 &&
+	test_cmp expected renamed_file
+'
+
+test_expect_success 'setup spurious "refusing to lose untracked" message' '
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	> irrelevant_file &&
+	printf "1\n2\n3\n4\n5\n6\n7\n8\n" >original_file &&
+	git add irrelevant_file original_file &&
+	git commit -mA &&
+
+	git checkout -b rename &&
+	git mv original_file renamed_file &&
+	git commit -mB &&
+
+	git checkout master &&
+	git rm original_file &&
+	git commit -mC
+'
+
+test_expect_success 'no spurious "refusing to lose untracked" message' '
+	git checkout master^0 &&
+	test_must_fail git merge rename^0 2>errors.txt &&
+	! grep "refusing to lose untracked file" errors.txt
+'
+
+test_expect_success 'do not follow renames for empty files' '
+	git checkout -f -b empty-base &&
+	>empty1 &&
+	git add empty1 &&
+	git commit -m base &&
+	echo content >empty1 &&
+	git add empty1 &&
+	git commit -m fill &&
+	git checkout -b empty-topic HEAD^ &&
+	git mv empty1 empty2 &&
+	git commit -m rename &&
+	test_must_fail git merge empty-base &&
+	test_must_be_empty empty2
+'
+
+test_done