26 files changed, 1126 insertions, 246 deletions

diff --git a/t/helper/test-oid-array.c b/t/helper/test-oid-array.c
index ce9fd5f091..b16cd0b11b 100644
--- a/t/helper/test-oid-array.c
+++ b/t/helper/test-oid-array.c
@@ -12,6 +12,9 @@ int cmd__oid_array(int argc, const char **argv)
 {
 	struct oid_array array = OID_ARRAY_INIT;
 	struct strbuf line = STRBUF_INIT;
+	int nongit_ok;
+
+	setup_git_directory_gently(&nongit_ok);
 
 	while (strbuf_getline(&line, stdin) != EOF) {
 		const char *arg;
diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index a3988bd4b8..463dc3a8be 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -30,6 +30,29 @@ test_expect_success 'extensions.partialclone without filter' '
 	git -C client fetch origin
 '
 
+test_expect_success 'convert shallow clone to partial clone' '
+	rm -fr server client &&
+	test_create_repo server &&
+	test_commit -C server my_commit 1 &&
+	test_commit -C server my_commit2 1 &&
+	git clone --depth=1 "file://$(pwd)/server" client &&
+	git -C client fetch --unshallow --filter="blob:none" &&
+	test_cmp_config -C client true remote.origin.promisor &&
+	test_cmp_config -C client blob:none remote.origin.partialclonefilter &&
+	test_cmp_config -C client 1 core.repositoryformatversion
+'
+
+test_expect_success 'convert shallow clone to partial clone must fail with any extension' '
+	rm -fr server client &&
+	test_create_repo server &&
+	test_commit -C server my_commit 1 &&
+	test_commit -C server my_commit2 1 &&
+	git clone --depth=1 "file://$(pwd)/server" client &&
+	test_cmp_config -C client 0 core.repositoryformatversion &&
+	git -C client config extensions.partialclone origin &&
+	test_must_fail git -C client fetch --unshallow --filter="blob:none"
+'
+
 test_expect_success 'missing reflog object, but promised by a commit, passes fsck' '
 	rm -rf repo &&
 	test_create_repo repo &&
diff --git a/t/t1050-large.sh b/t/t1050-large.sh
index 184b479a21..6a56d1ca24 100755
--- a/t/t1050-large.sh
+++ b/t/t1050-large.sh
@@ -12,6 +12,7 @@ file_size () {
 }
 
 test_expect_success setup '
+	test_oid_init &&
 	# clone does not allow us to pass core.bigfilethreshold to
 	# new repos, so set core.bigfilethreshold globally
 	git config --global core.bigfilethreshold 200k &&
@@ -64,7 +65,7 @@ test_expect_success 'add a large file or two' '
 	test $count = 1 &&
 	cnt=$(git show-index <"$idx" | wc -l) &&
 	test $cnt = 2 &&
-	for l in .git/objects/??/??????????????????????????????????????
+	for l in .git/objects/$OIDPATH_REGEX
 	do
 		test_path_is_file "$l" || continue
 		bad=t
@@ -177,7 +178,8 @@ test_expect_success 'git-show a large file' '
 
 test_expect_success 'index-pack' '
 	git clone file://"$(pwd)"/.git foo &&
-	GIT_DIR=non-existent git index-pack --strict --verify foo/.git/objects/pack/*.pack
+	GIT_DIR=non-existent git index-pack --object-format=$(test_oid algo) \
+		--strict --verify foo/.git/objects/pack/*.pack
 '
 
 test_expect_success 'repack' '
diff --git a/t/t1090-sparse-checkout-scope.sh b/t/t1090-sparse-checkout-scope.sh
index 40cc004326..f35a73dd20 100755
--- a/t/t1090-sparse-checkout-scope.sh
+++ b/t/t1090-sparse-checkout-scope.sh
@@ -63,7 +63,6 @@ test_expect_success 'in partial clone, sparse checkout only fetches needed blobs
 	git -C server commit -m message &&
 
 	test_config -C client core.sparsecheckout 1 &&
-	test_config -C client extensions.partialclone origin &&
 	echo "!/*" >client/.git/info/sparse-checkout &&
 	echo "/a" >>client/.git/info/sparse-checkout &&
 	git -C client fetch --filter=blob:none origin &&
diff --git a/t/t1302-repo-version.sh b/t/t1302-repo-version.sh
index ce4cff13bb..d60c042ce8 100755
--- a/t/t1302-repo-version.sh
+++ b/t/t1302-repo-version.sh
@@ -8,6 +8,10 @@ test_description='Test repository version check'
 . ./test-lib.sh
 
 test_expect_success 'setup' '
+	test_oid_cache <<-\EOF &&
+	version sha1:0
+	version sha256:1
+	EOF
 	cat >test.patch <<-\EOF &&
 	diff --git a/test.txt b/test.txt
 	new file mode 100644
@@ -23,7 +27,7 @@ test_expect_success 'setup' '
 '
 
 test_expect_success 'gitdir selection on normal repos' '
-	echo 0 >expect &&
+	echo $(test_oid version) >expect &&
 	git config core.repositoryformatversion >actual &&
 	git -C test config core.repositoryformatversion >actual2 &&
 	test_cmp expect actual &&
diff --git a/t/t2203-add-intent.sh b/t/t2203-add-intent.sh
index 5bbe8dcce4..8a5d55054f 100755
--- a/t/t2203-add-intent.sh
+++ b/t/t2203-add-intent.sh
@@ -232,17 +232,54 @@ test_expect_success 'double rename detection in status' '
 	)
 '
 
-test_expect_success 'diff-files/diff-cached shows ita as new/not-new files' '
+test_expect_success 'i-t-a files shown as new for "diff", "diff-files"; not-new for "diff --cached"' '
 	git reset --hard &&
-	echo new >new-ita &&
-	git add -N new-ita &&
+	: >empty &&
+	content="foo" &&
+	echo "$content" >not-empty &&
+
+	hash_e=$(git hash-object empty) &&
+	hash_n=$(git hash-object not-empty) &&
+	hash_t=$(git hash-object -t tree /dev/null) &&
+
+	cat >expect.diff_p <<-EOF &&
+	diff --git a/empty b/empty
+	new file mode 100644
+	index 0000000..$(git rev-parse --short $hash_e)
+	diff --git a/not-empty b/not-empty
+	new file mode 100644
+	index 0000000..$(git rev-parse --short $hash_n)
+	--- /dev/null
+	+++ b/not-empty
+	@@ -0,0 +1 @@
+	+$content
+	EOF
+	cat >expect.diff_s <<-EOF &&
+	 create mode 100644 empty
+	 create mode 100644 not-empty
+	EOF
+	cat >expect.diff_a <<-EOF &&
+	:000000 100644 0000000 $(git rev-parse --short $hash_t) A$(printf "\t")empty
+	:000000 100644 0000000 $(git rev-parse --short $hash_t) A$(printf "\t")not-empty
+	EOF
+
+	git add -N empty not-empty &&
+
+	git diff >actual &&
+	test_cmp expect.diff_p actual &&
+
 	git diff --summary >actual &&
-	echo " create mode 100644 new-ita" >expected &&
-	test_cmp expected actual &&
-	git diff --cached --summary >actual2 &&
-	test_must_be_empty actual2
-'
+	test_cmp expect.diff_s actual &&
+
+	git diff-files -p >actual &&
+	test_cmp expect.diff_p actual &&
 
+	git diff-files --abbrev >actual &&
+	test_cmp expect.diff_a actual &&
+
+	git diff --cached >actual &&
+	test_must_be_empty actual
+'
 
 test_expect_success '"diff HEAD" includes ita as new files' '
 	git reset --hard &&
diff --git a/t/t2401-worktree-prune.sh b/t/t2401-worktree-prune.sh
index b7d6d5d45a..a6ce7f590b 100755
--- a/t/t2401-worktree-prune.sh
+++ b/t/t2401-worktree-prune.sh
@@ -92,4 +92,28 @@ test_expect_success 'not prune proper checkouts' '
 	test -d .git/worktrees/nop
 '
 
+test_expect_success 'prune duplicate (linked/linked)' '
+	test_when_finished rm -fr .git/worktrees w1 w2 &&
+	git worktree add --detach w1 &&
+	git worktree add --detach w2 &&
+	sed "s/w2/w1/" .git/worktrees/w2/gitdir >.git/worktrees/w2/gitdir.new &&
+	mv .git/worktrees/w2/gitdir.new .git/worktrees/w2/gitdir &&
+	git worktree prune --verbose >actual &&
+	test_i18ngrep "duplicate entry" actual &&
+	test -d .git/worktrees/w1 &&
+	! test -d .git/worktrees/w2
+'
+
+test_expect_success 'prune duplicate (main/linked)' '
+	test_when_finished rm -fr repo wt &&
+	test_create_repo repo &&
+	test_commit -C repo x &&
+	git -C repo worktree add --detach ../wt &&
+	rm -fr wt &&
+	mv repo wt &&
+	git -C wt worktree prune --verbose >actual &&
+	test_i18ngrep "duplicate entry" actual &&
+	! test -d .git/worktrees/wt
+'
+
 test_done
diff --git a/t/t2403-worktree-move.sh b/t/t2403-worktree-move.sh
index 939d18d728..a4e1a178e0 100755
--- a/t/t2403-worktree-move.sh
+++ b/t/t2403-worktree-move.sh
@@ -112,6 +112,27 @@ test_expect_success 'move locked worktree (force)' '
 	git worktree move --force --force flump ploof
 '
 
+test_expect_success 'refuse to move worktree atop existing path' '
+	>bobble &&
+	git worktree add --detach beeble &&
+	test_must_fail git worktree move beeble bobble
+'
+
+test_expect_success 'move atop existing but missing worktree' '
+	git worktree add --detach gnoo &&
+	git worktree add --detach pneu &&
+	rm -fr pneu &&
+	test_must_fail git worktree move gnoo pneu &&
+	git worktree move --force gnoo pneu &&
+
+	git worktree add --detach nu &&
+	git worktree lock nu &&
+	rm -fr nu &&
+	test_must_fail git worktree move pneu nu &&
+	test_must_fail git worktree --force move pneu nu &&
+	git worktree move --force --force pneu nu
+'
+
 test_expect_success 'move a repo with uninitialized submodule' '
 	git init withsub &&
 	(
diff --git a/t/t2404-worktree-config.sh b/t/t2404-worktree-config.sh
index 286121d8de..9536d10919 100755
--- a/t/t2404-worktree-config.sh
+++ b/t/t2404-worktree-config.sh
@@ -23,8 +23,10 @@ test_expect_success 'config --worktree without extension' '
 '
 
 test_expect_success 'enable worktreeConfig extension' '
+	git config core.repositoryformatversion 1 &&
 	git config extensions.worktreeConfig true &&
-	test_cmp_config true extensions.worktreeConfig
+	test_cmp_config true extensions.worktreeConfig &&
+	test_cmp_config 1 core.repositoryformatversion
 '
 
 test_expect_success 'config is shared as before' '
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 411a70b0ce..b6aa04bbec 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -323,11 +323,11 @@ test_expect_success 'git branch --list -v with --abbrev' '
 
 test_expect_success 'git branch --column' '
 	COLUMNS=81 git branch --column=column >actual &&
-	cat >expected <<\EOF &&
+	cat >expect <<\EOF &&
   a/b/c     bam       foo       l       * master    mb        o/o       q
   abc       bar       j/k       m/m       master2   n         o/p       r
 EOF
-	test_cmp expected actual
+	test_cmp expect actual
 '
 
 test_expect_success 'git branch --column with an extremely long branch name' '
@@ -336,7 +336,7 @@ test_expect_success 'git branch --column with an extremely long branch name' '
 	test_when_finished "git branch -d $long" &&
 	git branch $long &&
 	COLUMNS=80 git branch --column=column >actual &&
-	cat >expected <<EOF &&
+	cat >expect <<EOF &&
   a/b/c
   abc
   bam
@@ -355,7 +355,7 @@ test_expect_success 'git branch --column with an extremely long branch name' '
   r
   $long
 EOF
-	test_cmp expected actual
+	test_cmp expect actual
 '
 
 test_expect_success 'git branch with column.*' '
@@ -364,11 +364,11 @@ test_expect_success 'git branch with column.*' '
 	COLUMNS=80 git branch >actual &&
 	git config --unset column.branch &&
 	git config --unset column.ui &&
-	cat >expected <<\EOF &&
+	cat >expect <<\EOF &&
   a/b/c   bam   foo   l   * master    mb   o/o   q
   abc     bar   j/k   m/m   master2   n    o/p   r
 EOF
-	test_cmp expected actual
+	test_cmp expect actual
 '
 
 test_expect_success 'git branch --column -v should fail' '
@@ -379,7 +379,7 @@ test_expect_success 'git branch -v with column.ui ignored' '
 	git config column.ui column &&
 	COLUMNS=80 git branch -v | cut -c -10 | sed "s/ *$//" >actual &&
 	git config --unset column.ui &&
-	cat >expected <<\EOF &&
+	cat >expect <<\EOF &&
   a/b/c
   abc
   bam
@@ -397,12 +397,12 @@ test_expect_success 'git branch -v with column.ui ignored' '
   q
   r
 EOF
-	test_cmp expected actual
+	test_cmp expect actual
 '
 
 mv .git/config .git/config-saved
 
-test_expect_success 'git branch -m q q2 without config should succeed' '
+test_expect_success SHA1 'git branch -m q q2 without config should succeed' '
 	git branch -m q q2 &&
 	git branch -m q2 q
 '
@@ -835,32 +835,42 @@ test_expect_success 'branch from tag w/--track causes failure' '
 '
 
 test_expect_success '--set-upstream-to fails on multiple branches' '
-	test_must_fail git branch --set-upstream-to master a b c
+	echo "fatal: too many arguments to set new upstream" >expect &&
+	test_must_fail git branch --set-upstream-to master a b c 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success '--set-upstream-to fails on detached HEAD' '
 	git checkout HEAD^{} &&
-	test_must_fail git branch --set-upstream-to master &&
-	git checkout -
+	test_when_finished git checkout - &&
+	echo "fatal: could not set upstream of HEAD to master when it does not point to any branch." >expect &&
+	test_must_fail git branch --set-upstream-to master 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success '--set-upstream-to fails on a missing dst branch' '
-	test_must_fail git branch --set-upstream-to master does-not-exist
+	echo "fatal: branch '"'"'does-not-exist'"'"' does not exist" >expect &&
+	test_must_fail git branch --set-upstream-to master does-not-exist 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success '--set-upstream-to fails on a missing src branch' '
-	test_must_fail git branch --set-upstream-to does-not-exist master
+	test_must_fail git branch --set-upstream-to does-not-exist master 2>err &&
+	test_i18ngrep "the requested upstream branch '"'"'does-not-exist'"'"' does not exist" err
 '
 
 test_expect_success '--set-upstream-to fails on a non-ref' '
-	test_must_fail git branch --set-upstream-to HEAD^{}
+	echo "fatal: Cannot setup tracking information; starting point '"'"'HEAD^{}'"'"' is not a branch." >expect &&
+	test_must_fail git branch --set-upstream-to HEAD^{} 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success '--set-upstream-to fails on locked config' '
 	test_when_finished "rm -f .git/config.lock" &&
 	>.git/config.lock &&
 	git branch locked &&
-	test_must_fail git branch --set-upstream-to locked
+	test_must_fail git branch --set-upstream-to locked 2>err &&
+	test_i18ngrep "could not lock config file .git/config: File exists" err
 '
 
 test_expect_success 'use --set-upstream-to modify HEAD' '
@@ -881,14 +891,17 @@ test_expect_success 'use --set-upstream-to modify a particular branch' '
 '
 
 test_expect_success '--unset-upstream should fail if given a non-existent branch' '
-	test_must_fail git branch --unset-upstream i-dont-exist
+	echo "fatal: Branch '"'"'i-dont-exist'"'"' has no upstream information" >expect &&
+	test_must_fail git branch --unset-upstream i-dont-exist 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success '--unset-upstream should fail if config is locked' '
 	test_when_finished "rm -f .git/config.lock" &&
 	git branch --set-upstream-to locked &&
 	>.git/config.lock &&
-	test_must_fail git branch --unset-upstream
+	test_must_fail git branch --unset-upstream 2>err &&
+	test_i18ngrep "could not lock config file .git/config: File exists" err
 '
 
 test_expect_success 'test --unset-upstream on HEAD' '
@@ -900,17 +913,23 @@ test_expect_success 'test --unset-upstream on HEAD' '
 	test_must_fail git config branch.master.remote &&
 	test_must_fail git config branch.master.merge &&
 	# fail for a branch without upstream set
-	test_must_fail git branch --unset-upstream
+	echo "fatal: Branch '"'"'master'"'"' has no upstream information" >expect &&
+	test_must_fail git branch --unset-upstream 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success '--unset-upstream should fail on multiple branches' '
-	test_must_fail git branch --unset-upstream a b c
+	echo "fatal: too many arguments to unset upstream" >expect &&
+	test_must_fail git branch --unset-upstream a b c 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success '--unset-upstream should fail on detached HEAD' '
 	git checkout HEAD^{} &&
-	test_must_fail git branch --unset-upstream &&
-	git checkout -
+	test_when_finished git checkout - &&
+	echo "fatal: could not unset upstream of HEAD when it does not point to any branch." >expect &&
+	test_must_fail git branch --unset-upstream 2>err &&
+	test_i18ncmp expect err
 '
 
 test_expect_success 'test --unset-upstream on a particular branch' '
@@ -922,17 +941,17 @@ test_expect_success 'test --unset-upstream on a particular branch' '
 '
 
 test_expect_success 'disabled option --set-upstream fails' '
-    test_must_fail git branch --set-upstream origin/master
+	test_must_fail git branch --set-upstream origin/master
 '
 
 test_expect_success '--set-upstream-to notices an error to set branch as own upstream' '
 	git branch --set-upstream-to refs/heads/my13 my13 2>actual &&
-	cat >expected <<-\EOF &&
+	cat >expect <<-\EOF &&
 	warning: Not setting branch my13 as its own upstream.
 	EOF
 	test_expect_code 1 git config branch.my13.remote &&
 	test_expect_code 1 git config branch.my13.merge &&
-	test_i18ncmp expected actual
+	test_i18ncmp expect actual
 '
 
 # Keep this test last, as it changes the current branch
diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index a1bc3e2001..b454f400eb 100755
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -420,7 +420,7 @@ test_expect_success 'with --autosquash and --exec' '
 	git commit --fixup B B.t &&
 	write_script show.sh <<-\EOF &&
 	subject="$(git show -s --format=%s HEAD)"
-	content="$(git diff HEAD^! | tail -n 1)"
+	content="$(git diff HEAD^ HEAD | tail -n 1)"
 	echo "$subject: $content"
 	EOF
 	test_tick &&
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 575e079cc2..958c2da56e 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -81,16 +81,16 @@ test_expect_success 'format-patch --ignore-if-in-upstream handles tags' '
 '
 
 test_expect_success "format-patch doesn't consider merge commits" '
-	git checkout -b slave master &&
+	git checkout -b feature master &&
 	echo "Another line" >>file &&
 	test_tick &&
-	git commit -am "Slave change #1" &&
+	git commit -am "Feature branch change #1" &&
 	echo "Yet another line" >>file &&
 	test_tick &&
-	git commit -am "Slave change #2" &&
+	git commit -am "Feature branch change #2" &&
 	git checkout -b merger master &&
 	test_tick &&
-	git merge --no-ff slave &&
+	git merge --no-ff feature &&
 	git format-patch -3 --stdout >patch &&
 	grep "^From " patch >from &&
 	test_line_count = 3 from
diff --git a/t/t4068-diff-symmetric.sh b/t/t4068-diff-symmetric.sh
new file mode 100755
index 0000000000..31d17a5af0
--- /dev/null
+++ b/t/t4068-diff-symmetric.sh
@@ -0,0 +1,91 @@
+#!/bin/sh
+
+test_description='behavior of diff with symmetric-diff setups'
+
+. ./test-lib.sh
+
+# build these situations:
+#  - normal merge with one merge base (br1...b2r);
+#  - criss-cross merge ie 2 merge bases (br1...master);
+#  - disjoint subgraph (orphan branch, br3...master).
+#
+#     B---E   <-- master
+#    / \ /
+#   A   X
+#    \ / \
+#     C---D--G   <-- br1
+#      \    /
+#       ---F   <-- br2
+#
+#  H  <-- br3
+#
+# We put files into a few commits so that we can verify the
+# output as well.
+
+test_expect_success setup '
+	git commit --allow-empty -m A &&
+	echo b >b &&
+	git add b &&
+	git commit -m B &&
+	git checkout -b br1 HEAD^ &&
+	echo c >c &&
+	git add c &&
+	git commit -m C &&
+	git tag commit-C &&
+	git merge -m D master &&
+	git tag commit-D &&
+	git checkout master &&
+	git merge -m E commit-C &&
+	git checkout -b br2 commit-C &&
+	echo f >f &&
+	git add f &&
+	git commit -m F &&
+	git checkout br1 &&
+	git merge -m G br2 &&
+	git checkout --orphan br3 &&
+	git commit -m H
+'
+
+test_expect_success 'diff with one merge base' '
+	git diff commit-D...br1 >tmp &&
+	tail -n 1 tmp >actual &&
+	echo +f >expect &&
+	test_cmp expect actual
+'
+
+# The output (in tmp) can have +b or +c depending
+# on which merge base (commit B or C) is picked.
+# It should have one of those two, which comes out
+# to seven lines.
+test_expect_success 'diff with two merge bases' '
+	git diff br1...master >tmp 2>err &&
+	test_line_count = 7 tmp &&
+	test_line_count = 1 err
+'
+
+test_expect_success 'diff with no merge bases' '
+	test_must_fail git diff br2...br3 >tmp 2>err &&
+	test_i18ngrep "fatal: br2...br3: no merge base" err
+'
+
+test_expect_success 'diff with too many symmetric differences' '
+	test_must_fail git diff br1...master br2...br3 >tmp 2>err &&
+	test_i18ngrep "usage" err
+'
+
+test_expect_success 'diff with symmetric difference and extraneous arg' '
+	test_must_fail git diff master br1...master >tmp 2>err &&
+	test_i18ngrep "usage" err
+'
+
+test_expect_success 'diff with two ranges' '
+	test_must_fail git diff master br1..master br2..br3 >tmp 2>err &&
+	test_i18ngrep "usage" err
+'
+
+test_expect_success 'diff with ranges and extra arg' '
+	test_must_fail git diff master br1..master commit-D >tmp 2>err &&
+	test_i18ngrep "usage" err
+'
+
+test_done
diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
index 410a09b0dd..746cdb626e 100755
--- a/t/t5300-pack-object.sh
+++ b/t/t5300-pack-object.sh
@@ -12,7 +12,8 @@ TRASH=$(pwd)
 
 test_expect_success \
     'setup' \
-    'rm -f .git/index* &&
+    'test_oid_init &&
+     rm -f .git/index* &&
      perl -e "print \"a\" x 4096;" > a &&
      perl -e "print \"b\" x 4096;" > b &&
      perl -e "print \"c\" x 4096;" > c &&
@@ -412,18 +413,18 @@ test_expect_success 'set up pack for non-repo tests' '
 '
 
 test_expect_success 'index-pack --stdin complains of non-repo' '
-	nongit test_must_fail git index-pack --stdin <foo.pack &&
+	nongit test_must_fail git index-pack --object-format=$(test_oid algo) --stdin <foo.pack &&
 	test_path_is_missing non-repo/.git
 '
 
 test_expect_success 'index-pack <pack> works in non-repo' '
-	nongit git index-pack ../foo.pack &&
+	nongit git index-pack --object-format=$(test_oid algo) ../foo.pack &&
 	test_path_is_file foo.idx
 '
 
 test_expect_success 'index-pack --strict <pack> works in non-repo' '
 	rm -f foo.idx &&
-	nongit git index-pack --strict ../foo.pack &&
+	nongit git index-pack --strict --object-format=$(test_oid algo) ../foo.pack &&
 	test_path_is_file foo.idx
 '
 
diff --git a/t/t5302-pack-index.sh b/t/t5302-pack-index.sh
index ad07f2f7fc..8981c9b90e 100755
--- a/t/t5302-pack-index.sh
+++ b/t/t5302-pack-index.sh
@@ -7,65 +7,65 @@ test_description='pack index with 64-bit offsets and object CRC'
 . ./test-lib.sh
 
 test_expect_success 'setup' '
-     test_oid_init &&
-     rawsz=$(test_oid rawsz) &&
-     rm -rf .git &&
-     git init &&
-     git config pack.threads 1 &&
-     i=1 &&
-     while test $i -le 100
-     do
-         iii=$(printf '%03i' $i)
-	 test-tool genrandom "bar" 200 > wide_delta_$iii &&
-	 test-tool genrandom "baz $iii" 50 >> wide_delta_$iii &&
-	 test-tool genrandom "foo"$i 100 > deep_delta_$iii &&
-	 test-tool genrandom "foo"$(expr $i + 1) 100 >> deep_delta_$iii &&
-	 test-tool genrandom "foo"$(expr $i + 2) 100 >> deep_delta_$iii &&
-         echo $iii >file_$iii &&
-	 test-tool genrandom "$iii" 8192 >>file_$iii &&
-         git update-index --add file_$iii deep_delta_$iii wide_delta_$iii &&
-         i=$(expr $i + 1) || return 1
-     done &&
-     { echo 101 && test-tool genrandom 100 8192; } >file_101 &&
-     git update-index --add file_101 &&
-     tree=$(git write-tree) &&
-     commit=$(git commit-tree $tree </dev/null) && {
-	 echo $tree &&
-	 git ls-tree $tree | sed -e "s/.* \\([0-9a-f]*\\)	.*/\\1/"
-     } >obj-list &&
-     git update-ref HEAD $commit
+	test_oid_init &&
+	rawsz=$(test_oid rawsz) &&
+	rm -rf .git &&
+	git init &&
+	git config pack.threads 1 &&
+	i=1 &&
+	while test $i -le 100
+	do
+		iii=$(printf '%03i' $i)
+		test-tool genrandom "bar" 200 > wide_delta_$iii &&
+		test-tool genrandom "baz $iii" 50 >> wide_delta_$iii &&
+		test-tool genrandom "foo"$i 100 > deep_delta_$iii &&
+		test-tool genrandom "foo"$(expr $i + 1) 100 >> deep_delta_$iii &&
+		test-tool genrandom "foo"$(expr $i + 2) 100 >> deep_delta_$iii &&
+		echo $iii >file_$iii &&
+		test-tool genrandom "$iii" 8192 >>file_$iii &&
+		git update-index --add file_$iii deep_delta_$iii wide_delta_$iii &&
+		i=$(expr $i + 1) || return 1
+	done &&
+	{ echo 101 && test-tool genrandom 100 8192; } >file_101 &&
+	git update-index --add file_101 &&
+	tree=$(git write-tree) &&
+	commit=$(git commit-tree $tree </dev/null) && {
+		echo $tree &&
+		git ls-tree $tree | sed -e "s/.* \\([0-9a-f]*\\)	.*/\\1/"
+	} >obj-list &&
+	git update-ref HEAD $commit
 '
 
-test_expect_success \
-    'pack-objects with index version 1' \
-    'pack1=$(git pack-objects --index-version=1 test-1 <obj-list) &&
-     git verify-pack -v "test-1-${pack1}.pack"'
+test_expect_success 'pack-objects with index version 1' '
+	pack1=$(git pack-objects --index-version=1 test-1 <obj-list) &&
+	git verify-pack -v "test-1-${pack1}.pack"
+'
 
-test_expect_success \
-    'pack-objects with index version 2' \
-    'pack2=$(git pack-objects --index-version=2 test-2 <obj-list) &&
-     git verify-pack -v "test-2-${pack2}.pack"'
+test_expect_success 'pack-objects with index version 2' '
+	pack2=$(git pack-objects --index-version=2 test-2 <obj-list) &&
+	git verify-pack -v "test-2-${pack2}.pack"
+'
 
-test_expect_success \
-    'both packs should be identical' \
-    'cmp "test-1-${pack1}.pack" "test-2-${pack2}.pack"'
+test_expect_success 'both packs should be identical' '
+	cmp "test-1-${pack1}.pack" "test-2-${pack2}.pack"
+'
 
-test_expect_success \
-    'index v1 and index v2 should be different' \
-    '! cmp "test-1-${pack1}.idx" "test-2-${pack2}.idx"'
+test_expect_success 'index v1 and index v2 should be different' '
+	! cmp "test-1-${pack1}.idx" "test-2-${pack2}.idx"
+'
 
-test_expect_success \
-    'index-pack with index version 1' \
-    'git index-pack --index-version=1 -o 1.idx "test-1-${pack1}.pack"'
+test_expect_success 'index-pack with index version 1' '
+	git index-pack --index-version=1 -o 1.idx "test-1-${pack1}.pack"
+'
 
-test_expect_success \
-    'index-pack with index version 2' \
-    'git index-pack --index-version=2 -o 2.idx "test-1-${pack1}.pack"'
+test_expect_success 'index-pack with index version 2' '
+	git index-pack --index-version=2 -o 2.idx "test-1-${pack1}.pack"
+'
 
-test_expect_success \
-    'index-pack results should match pack-objects ones' \
-    'cmp "test-1-${pack1}.idx" "1.idx" &&
-     cmp "test-2-${pack2}.idx" "2.idx"'
+test_expect_success 'index-pack results should match pack-objects ones' '
+	cmp "test-1-${pack1}.idx" "1.idx" &&
+	cmp "test-2-${pack2}.idx" "2.idx"
+'
 
 test_expect_success 'index-pack --verify on index version 1' '
 	git index-pack --verify "test-1-${pack1}.pack"
@@ -75,13 +75,13 @@ test_expect_success 'index-pack --verify on index version 2' '
 	git index-pack --verify "test-2-${pack2}.pack"
 '
 
-test_expect_success \
-    'pack-objects --index-version=2, is not accepted' \
-    'test_must_fail git pack-objects --index-version=2, test-3 <obj-list'
+test_expect_success 'pack-objects --index-version=2, is not accepted' '
+	test_must_fail git pack-objects --index-version=2, test-3 <obj-list
+'
 
-test_expect_success \
-    'index v2: force some 64-bit offsets with pack-objects' \
-    'pack3=$(git pack-objects --index-version=2,0x40000 test-3 <obj-list)'
+test_expect_success 'index v2: force some 64-bit offsets with pack-objects' '
+	pack3=$(git pack-objects --index-version=2,0x40000 test-3 <obj-list)
+'
 
 if msg=$(git verify-pack -v "test-3-${pack3}.pack" 2>&1) ||
 	! (echo "$msg" | grep "pack too large .* off_t")
@@ -91,21 +91,21 @@ else
 	say "# skipping tests concerning 64-bit offsets"
 fi
 
-test_expect_success OFF64_T \
-    'index v2: verify a pack with some 64-bit offsets' \
-    'git verify-pack -v "test-3-${pack3}.pack"'
+test_expect_success OFF64_T 'index v2: verify a pack with some 64-bit offsets' '
+	git verify-pack -v "test-3-${pack3}.pack"
+'
 
-test_expect_success OFF64_T \
-    '64-bit offsets: should be different from previous index v2 results' \
-    '! cmp "test-2-${pack2}.idx" "test-3-${pack3}.idx"'
+test_expect_success OFF64_T '64-bit offsets: should be different from previous index v2 results' '
+	! cmp "test-2-${pack2}.idx" "test-3-${pack3}.idx"
+'
 
-test_expect_success OFF64_T \
-    'index v2: force some 64-bit offsets with index-pack' \
-    'git index-pack --index-version=2,0x40000 -o 3.idx "test-1-${pack1}.pack"'
+test_expect_success OFF64_T 'index v2: force some 64-bit offsets with index-pack' '
+	git index-pack --index-version=2,0x40000 -o 3.idx "test-1-${pack1}.pack"
+'
 
-test_expect_success OFF64_T \
-    '64-bit offsets: index-pack result should match pack-objects one' \
-    'cmp "test-3-${pack3}.idx" "3.idx"'
+test_expect_success OFF64_T '64-bit offsets: index-pack result should match pack-objects one' '
+	cmp "test-3-${pack3}.idx" "3.idx"
+'
 
 test_expect_success OFF64_T 'index-pack --verify on 64-bit offset v2 (cheat)' '
 	# This cheats by knowing which lower offset should still be encoded
@@ -120,135 +120,143 @@ test_expect_success OFF64_T 'index-pack --verify on 64-bit offset v2' '
 # returns the object number for given object in given pack index
 index_obj_nr()
 {
-    idx_file=$1
-    object_sha1=$2
-    nr=0
-    git show-index < $idx_file |
-    while read offs sha1 extra
-    do
-      nr=$(($nr + 1))
-      test "$sha1" = "$object_sha1" || continue
-      echo "$(($nr - 1))"
-      break
-    done
+	idx_file=$1
+	object_sha1=$2
+	nr=0
+	git show-index < $idx_file |
+	while read offs sha1 extra
+	do
+	  nr=$(($nr + 1))
+	  test "$sha1" = "$object_sha1" || continue
+	  echo "$(($nr - 1))"
+	  break
+	done
 }
 
 # returns the pack offset for given object as found in given pack index
 index_obj_offset()
 {
-    idx_file=$1
-    object_sha1=$2
-    git show-index < $idx_file | grep $object_sha1 |
-    ( read offs extra && echo "$offs" )
+	idx_file=$1
+	object_sha1=$2
+	git show-index < $idx_file | grep $object_sha1 |
+	( read offs extra && echo "$offs" )
 }
 
-test_expect_success \
-    '[index v1] 1) stream pack to repository' \
-    'git index-pack --index-version=1 --stdin < "test-1-${pack1}.pack" &&
-     git prune-packed &&
-     git count-objects | ( read nr rest && test "$nr" -eq 1 ) &&
-     cmp "test-1-${pack1}.pack" ".git/objects/pack/pack-${pack1}.pack" &&
-     cmp "test-1-${pack1}.idx"  ".git/objects/pack/pack-${pack1}.idx"'
+test_expect_success '[index v1] 1) stream pack to repository' '
+	git index-pack --index-version=1 --stdin < "test-1-${pack1}.pack" &&
+	git prune-packed &&
+	git count-objects | ( read nr rest && test "$nr" -eq 1 ) &&
+	cmp "test-1-${pack1}.pack" ".git/objects/pack/pack-${pack1}.pack" &&
+	cmp "test-1-${pack1}.idx"	".git/objects/pack/pack-${pack1}.idx"
+'
 
 test_expect_success \
-    '[index v1] 2) create a stealth corruption in a delta base reference' \
-    '# This test assumes file_101 is a delta smaller than 16 bytes.
-     # It should be against file_100 but we substitute its base for file_099
-     sha1_101=$(git hash-object file_101) &&
-     sha1_099=$(git hash-object file_099) &&
-     offs_101=$(index_obj_offset 1.idx $sha1_101) &&
-     nr_099=$(index_obj_nr 1.idx $sha1_099) &&
-     chmod +w ".git/objects/pack/pack-${pack1}.pack" &&
-     recordsz=$((rawsz + 4)) &&
-     dd of=".git/objects/pack/pack-${pack1}.pack" seek=$(($offs_101 + 1)) \
-        if=".git/objects/pack/pack-${pack1}.idx" \
-        skip=$((4 + 256 * 4 + $nr_099 * recordsz)) \
-        bs=1 count=$rawsz conv=notrunc &&
-     git cat-file blob $sha1_101 > file_101_foo1'
+	'[index v1] 2) create a stealth corruption in a delta base reference' '
+	# This test assumes file_101 is a delta smaller than 16 bytes.
+	# It should be against file_100 but we substitute its base for file_099
+	sha1_101=$(git hash-object file_101) &&
+	sha1_099=$(git hash-object file_099) &&
+	offs_101=$(index_obj_offset 1.idx $sha1_101) &&
+	nr_099=$(index_obj_nr 1.idx $sha1_099) &&
+	chmod +w ".git/objects/pack/pack-${pack1}.pack" &&
+	recordsz=$((rawsz + 4)) &&
+	dd of=".git/objects/pack/pack-${pack1}.pack" seek=$(($offs_101 + 1)) \
+	       if=".git/objects/pack/pack-${pack1}.idx" \
+	       skip=$((4 + 256 * 4 + $nr_099 * recordsz)) \
+	       bs=1 count=$rawsz conv=notrunc &&
+	git cat-file blob $sha1_101 > file_101_foo1
+'
 
 test_expect_success \
-    '[index v1] 3) corrupted delta happily returned wrong data' \
-    'test -f file_101_foo1 && ! cmp file_101 file_101_foo1'
+	'[index v1] 3) corrupted delta happily returned wrong data' '
+	test -f file_101_foo1 && ! cmp file_101 file_101_foo1
+'
 
 test_expect_success \
-    '[index v1] 4) confirm that the pack is actually corrupted' \
-    'test_must_fail git fsck --full $commit'
+	'[index v1] 4) confirm that the pack is actually corrupted' '
+	test_must_fail git fsck --full $commit
+'
 
 test_expect_success \
-    '[index v1] 5) pack-objects happily reuses corrupted data' \
-    'pack4=$(git pack-objects test-4 <obj-list) &&
-     test -f "test-4-${pack4}.pack"'
+	'[index v1] 5) pack-objects happily reuses corrupted data' '
+	pack4=$(git pack-objects test-4 <obj-list) &&
+	test -f "test-4-${pack4}.pack"
+'
 
-test_expect_success \
-    '[index v1] 6) newly created pack is BAD !' \
-    'test_must_fail git verify-pack -v "test-4-${pack4}.pack"'
+test_expect_success '[index v1] 6) newly created pack is BAD !' '
+	test_must_fail git verify-pack -v "test-4-${pack4}.pack"
+'
 
-test_expect_success \
-    '[index v2] 1) stream pack to repository' \
-    'rm -f .git/objects/pack/* &&
-     git index-pack --index-version=2 --stdin < "test-1-${pack1}.pack" &&
-     git prune-packed &&
-     git count-objects | ( read nr rest && test "$nr" -eq 1 ) &&
-     cmp "test-1-${pack1}.pack" ".git/objects/pack/pack-${pack1}.pack" &&
-     cmp "test-2-${pack1}.idx"  ".git/objects/pack/pack-${pack1}.idx"'
+test_expect_success '[index v2] 1) stream pack to repository' '
+	rm -f .git/objects/pack/* &&
+	git index-pack --index-version=2 --stdin < "test-1-${pack1}.pack" &&
+	git prune-packed &&
+	git count-objects | ( read nr rest && test "$nr" -eq 1 ) &&
+	cmp "test-1-${pack1}.pack" ".git/objects/pack/pack-${pack1}.pack" &&
+	cmp "test-2-${pack1}.idx"	".git/objects/pack/pack-${pack1}.idx"
+'
 
 test_expect_success \
-    '[index v2] 2) create a stealth corruption in a delta base reference' \
-    '# This test assumes file_101 is a delta smaller than 16 bytes.
-     # It should be against file_100 but we substitute its base for file_099
-     sha1_101=$(git hash-object file_101) &&
-     sha1_099=$(git hash-object file_099) &&
-     offs_101=$(index_obj_offset 1.idx $sha1_101) &&
-     nr_099=$(index_obj_nr 1.idx $sha1_099) &&
-     chmod +w ".git/objects/pack/pack-${pack1}.pack" &&
-     dd of=".git/objects/pack/pack-${pack1}.pack" seek=$(($offs_101 + 1)) \
-        if=".git/objects/pack/pack-${pack1}.idx" \
-        skip=$((8 + 256 * 4 + $nr_099 * rawsz)) \
-        bs=1 count=$rawsz conv=notrunc &&
-     git cat-file blob $sha1_101 > file_101_foo2'
+	'[index v2] 2) create a stealth corruption in a delta base reference' '
+	# This test assumes file_101 is a delta smaller than 16 bytes.
+	# It should be against file_100 but we substitute its base for file_099
+	sha1_101=$(git hash-object file_101) &&
+	sha1_099=$(git hash-object file_099) &&
+	offs_101=$(index_obj_offset 1.idx $sha1_101) &&
+	nr_099=$(index_obj_nr 1.idx $sha1_099) &&
+	chmod +w ".git/objects/pack/pack-${pack1}.pack" &&
+	dd of=".git/objects/pack/pack-${pack1}.pack" seek=$(($offs_101 + 1)) \
+		if=".git/objects/pack/pack-${pack1}.idx" \
+		skip=$((8 + 256 * 4 + $nr_099 * rawsz)) \
+		bs=1 count=$rawsz conv=notrunc &&
+	git cat-file blob $sha1_101 > file_101_foo2
+'
 
 test_expect_success \
-    '[index v2] 3) corrupted delta happily returned wrong data' \
-    'test -f file_101_foo2 && ! cmp file_101 file_101_foo2'
+	'[index v2] 3) corrupted delta happily returned wrong data' '
+	test -f file_101_foo2 && ! cmp file_101 file_101_foo2
+'
 
 test_expect_success \
-    '[index v2] 4) confirm that the pack is actually corrupted' \
-    'test_must_fail git fsck --full $commit'
+	'[index v2] 4) confirm that the pack is actually corrupted' '
+	test_must_fail git fsck --full $commit
+'
 
 test_expect_success \
-    '[index v2] 5) pack-objects refuses to reuse corrupted data' \
-    'test_must_fail git pack-objects test-5 <obj-list &&
-     test_must_fail git pack-objects --no-reuse-object test-6 <obj-list'
+	'[index v2] 5) pack-objects refuses to reuse corrupted data' '
+	test_must_fail git pack-objects test-5 <obj-list &&
+	test_must_fail git pack-objects --no-reuse-object test-6 <obj-list
+'
 
 test_expect_success \
-    '[index v2] 6) verify-pack detects CRC mismatch' \
-    'rm -f .git/objects/pack/* &&
-     git index-pack --index-version=2 --stdin < "test-1-${pack1}.pack" &&
-     git verify-pack ".git/objects/pack/pack-${pack1}.pack" &&
-     obj=$(git hash-object file_001) &&
-     nr=$(index_obj_nr ".git/objects/pack/pack-${pack1}.idx" $obj) &&
-     chmod +w ".git/objects/pack/pack-${pack1}.idx" &&
-     printf xxxx | dd of=".git/objects/pack/pack-${pack1}.idx" conv=notrunc \
-        bs=1 count=4 seek=$((8 + 256 * 4 + $(wc -l <obj-list) * rawsz + $nr * 4)) &&
-     ( while read obj
-       do git cat-file -p $obj >/dev/null || exit 1
-       done <obj-list ) &&
-     test_must_fail git verify-pack ".git/objects/pack/pack-${pack1}.pack"
+	'[index v2] 6) verify-pack detects CRC mismatch' '
+	rm -f .git/objects/pack/* &&
+	git index-pack --index-version=2 --stdin < "test-1-${pack1}.pack" &&
+	git verify-pack ".git/objects/pack/pack-${pack1}.pack" &&
+	obj=$(git hash-object file_001) &&
+	nr=$(index_obj_nr ".git/objects/pack/pack-${pack1}.idx" $obj) &&
+	chmod +w ".git/objects/pack/pack-${pack1}.idx" &&
+	printf xxxx | dd of=".git/objects/pack/pack-${pack1}.idx" conv=notrunc \
+		bs=1 count=4 seek=$((8 + 256 * 4 + $(wc -l <obj-list) * rawsz + $nr * 4)) &&
+	 ( while read obj
+	   do git cat-file -p $obj >/dev/null || exit 1
+	   done <obj-list ) &&
+	test_must_fail git verify-pack ".git/objects/pack/pack-${pack1}.pack"
 '
 
 test_expect_success 'running index-pack in the object store' '
-    rm -f .git/objects/pack/* &&
-    cp test-1-${pack1}.pack .git/objects/pack/pack-${pack1}.pack &&
-    (
-	cd .git/objects/pack &&
-	git index-pack pack-${pack1}.pack
-    ) &&
-    test -f .git/objects/pack/pack-${pack1}.idx
+	rm -f .git/objects/pack/* &&
+	cp test-1-${pack1}.pack .git/objects/pack/pack-${pack1}.pack &&
+	(
+		cd .git/objects/pack &&
+		git index-pack pack-${pack1}.pack
+	) &&
+	test -f .git/objects/pack/pack-${pack1}.idx
 '
 
 test_expect_success 'index-pack --strict warns upon missing tagger in tag' '
-    sha=$(git rev-parse HEAD) &&
-    cat >wrong-tag <<EOF &&
+	sha=$(git rev-parse HEAD) &&
+	cat >wrong-tag <<EOF &&
 object $sha
 type commit
 tag guten tag
@@ -256,18 +264,18 @@ tag guten tag
 This is an invalid tag.
 EOF
 
-    tag=$(git hash-object -t tag -w --stdin <wrong-tag) &&
-    pack1=$(echo $tag $sha | git pack-objects tag-test) &&
-    echo remove tag object &&
-    thirtyeight=${tag#??} &&
-    rm -f .git/objects/${tag%$thirtyeight}/$thirtyeight &&
-    git index-pack --strict tag-test-${pack1}.pack 2>err &&
-    grep "^warning:.* expected .tagger. line" err
+	tag=$(git hash-object -t tag -w --stdin <wrong-tag) &&
+	pack1=$(echo $tag $sha | git pack-objects tag-test) &&
+	echo remove tag object &&
+	thirtyeight=${tag#??} &&
+	rm -f .git/objects/${tag%$thirtyeight}/$thirtyeight &&
+	git index-pack --strict tag-test-${pack1}.pack 2>err &&
+	grep "^warning:.* expected .tagger. line" err
 '
 
 test_expect_success 'index-pack --fsck-objects also warns upon missing tagger in tag' '
-    git index-pack --fsck-objects tag-test-${pack1}.pack 2>err &&
-    grep "^warning:.* expected .tagger. line" err
+	git index-pack --fsck-objects tag-test-${pack1}.pack 2>err &&
+	grep "^warning:.* expected .tagger. line" err
 '
 
 test_done
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index 8c54e34ef1..3557374312 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -871,9 +871,10 @@ test_expect_success 'shallow since with commit graph and already-seen commit' '
 
 	GIT_PROTOCOL=version=2 git upload-pack . <<-EOF >/dev/null
 	0012command=fetch
+	$(echo "object-format=$(test_oid algo)" | packetize)
 	00010013deepen-since 1
-	0032want $(git rev-parse other)
-	0032have $(git rev-parse master)
+	$(echo "want $(git rev-parse other)" | packetize)
+	$(echo "have $(git rev-parse master)" | packetize)
 	0000
 	EOF
 	)
@@ -999,7 +1000,6 @@ fetch_filter_blob_limit_zero () {
 	test_config -C "$SERVER" uploadpack.allowfilter 1 &&
 
 	git clone "$URL" client &&
-	test_config -C client extensions.partialclone origin &&
 
 	test_commit -C "$SERVER" two &&
 
diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh
index 50485300eb..483578b2d7 100755
--- a/t/t5550-http-fetch-dumb.sh
+++ b/t/t5550-http-fetch-dumb.sh
@@ -50,6 +50,24 @@ test_expect_success 'create password-protected repository' '
 	       "$HTTPD_DOCUMENT_ROOT_PATH/auth/dumb/repo.git"
 '
 
+test_expect_success 'create empty remote repository' '
+	git init --bare "$HTTPD_DOCUMENT_ROOT_PATH/empty.git" &&
+	(cd "$HTTPD_DOCUMENT_ROOT_PATH/empty.git" &&
+	 mkdir -p hooks &&
+	 write_script "hooks/post-update" <<-\EOF &&
+	 exec git update-server-info
+	EOF
+	 hooks/post-update
+	)
+'
+
+test_expect_success 'empty dumb HTTP repository has default hash algorithm' '
+	test_when_finished "rm -fr clone-empty" &&
+	git clone $HTTPD_URL/dumb/empty.git clone-empty &&
+	git -C clone-empty rev-parse --show-object-format >empty-format &&
+	test "$(cat empty-format)" = "$(test_oid algo)"
+'
+
 setup_askpass_helper
 
 test_expect_success 'cloning password-protected repository can fail' '
@@ -199,6 +217,28 @@ test_expect_success 'fetch packed objects' '
 	git clone $HTTPD_URL/dumb/repo_pack.git
 '
 
+test_expect_success 'http-fetch --packfile' '
+	# Arbitrary hash. Use rev-parse so that we get one of the correct
+	# length.
+	ARBITRARY=$(git -C "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git rev-parse HEAD) &&
+
+	git init packfileclient &&
+	p=$(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git && ls objects/pack/pack-*.pack) &&
+	git -C packfileclient http-fetch --packfile=$ARBITRARY "$HTTPD_URL"/dumb/repo_pack.git/$p >out &&
+
+	grep "^keep.[0-9a-f]\{16,\}$" out &&
+	cut -c6- out >packhash &&
+
+	# Ensure that the expected files are generated
+	test -e "packfileclient/.git/objects/pack/pack-$(cat packhash).pack" &&
+	test -e "packfileclient/.git/objects/pack/pack-$(cat packhash).idx" &&
+	test -e "packfileclient/.git/objects/pack/pack-$(cat packhash).keep" &&
+
+	# Ensure that it has the HEAD of repo_pack, at least
+	HASH=$(git -C "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git rev-parse HEAD) &&
+	git -C packfileclient cat-file -e "$HASH"
+'
+
 test_expect_success 'fetch notices corrupt pack' '
 	cp -R "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad1.git &&
 	(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad1.git &&
@@ -214,6 +254,14 @@ test_expect_success 'fetch notices corrupt pack' '
 	)
 '
 
+test_expect_success 'http-fetch --packfile with corrupt pack' '
+	rm -rf packfileclient &&
+	git init packfileclient &&
+	p=$(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad1.git && ls objects/pack/pack-*.pack) &&
+	test_must_fail git -C packfileclient http-fetch --packfile \
+		"$HTTPD_URL"/dumb/repo_bad1.git/$p
+'
+
 test_expect_success 'fetch notices corrupt idx' '
 	cp -R "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad2.git &&
 	(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad2.git &&
diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index be01cf7bb2..e40e9ed52f 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -209,6 +209,16 @@ test_expect_success 'GIT_CURL_VERBOSE redacts auth details' '
 	grep "Authorization: Basic <redacted>" trace
 '
 
+test_expect_success 'GIT_TRACE_CURL does not redact auth details if GIT_TRACE_REDACT=0' '
+	rm -rf redact-auth trace &&
+	set_askpass user@host pass@host &&
+	GIT_TRACE_REDACT=0 GIT_TRACE_CURL="$(pwd)/trace" \
+		git clone --bare "$HTTPD_URL/auth/smart/repo.git" redact-auth &&
+	expect_askpass both user@host &&
+
+	grep "Authorization: Basic [0-9a-zA-Z+/]" trace
+'
+
 test_expect_success 'disable dumb http on server' '
 	git --git-dir="$HTTPD_DOCUMENT_ROOT_PATH/repo.git" \
 		config http.getanyfile false
@@ -454,37 +464,37 @@ test_expect_success 'fetch by SHA-1 without tag following' '
 		--no-tags origin $(cat bar_hash)
 '
 
-test_expect_success 'GIT_REDACT_COOKIES redacts cookies' '
+test_expect_success 'cookies are redacted by default' '
 	rm -rf clone &&
 	echo "Set-Cookie: Foo=1" >cookies &&
 	echo "Set-Cookie: Bar=2" >>cookies &&
-	GIT_TRACE_CURL=true GIT_REDACT_COOKIES=Bar,Baz \
+	GIT_TRACE_CURL=true \
 		git -c "http.cookieFile=$(pwd)/cookies" clone \
 		$HTTPD_URL/smart/repo.git clone 2>err &&
-	grep "Cookie:.*Foo=1" err &&
+	grep "Cookie:.*Foo=<redacted>" err &&
 	grep "Cookie:.*Bar=<redacted>" err &&
+	! grep "Cookie:.*Foo=1" err &&
 	! grep "Cookie:.*Bar=2" err
 '
 
-test_expect_success 'GIT_REDACT_COOKIES redacts cookies when GIT_CURL_VERBOSE=1' '
+test_expect_success 'empty values of cookies are also redacted' '
 	rm -rf clone &&
-	echo "Set-Cookie: Foo=1" >cookies &&
-	echo "Set-Cookie: Bar=2" >>cookies &&
-	GIT_CURL_VERBOSE=1 GIT_REDACT_COOKIES=Bar,Baz \
+	echo "Set-Cookie: Foo=" >cookies &&
+	GIT_TRACE_CURL=true \
 		git -c "http.cookieFile=$(pwd)/cookies" clone \
 		$HTTPD_URL/smart/repo.git clone 2>err &&
-	grep "Cookie:.*Foo=1" err &&
-	grep "Cookie:.*Bar=<redacted>" err &&
-	! grep "Cookie:.*Bar=2" err
+	grep "Cookie:.*Foo=<redacted>" err
 '
 
-test_expect_success 'GIT_REDACT_COOKIES handles empty values' '
+test_expect_success 'GIT_TRACE_REDACT=0 disables cookie redaction' '
 	rm -rf clone &&
-	echo "Set-Cookie: Foo=" >cookies &&
-	GIT_TRACE_CURL=true GIT_REDACT_COOKIES=Foo \
+	echo "Set-Cookie: Foo=1" >cookies &&
+	echo "Set-Cookie: Bar=2" >>cookies &&
+	GIT_TRACE_REDACT=0 GIT_TRACE_CURL=true \
 		git -c "http.cookieFile=$(pwd)/cookies" clone \
 		$HTTPD_URL/smart/repo.git clone 2>err &&
-	grep "Cookie:.*Foo=<redacted>" err
+	grep "Cookie:.*Foo=1" err &&
+	grep "Cookie:.*Bar=2" err
 '
 
 test_expect_success 'GIT_TRACE_CURL_NO_DATA prevents data from being traced' '
diff --git a/t/t5562-http-backend-content-length.sh b/t/t5562-http-backend-content-length.sh
index 3f4ac71f83..c6ec625497 100755
--- a/t/t5562-http-backend-content-length.sh
+++ b/t/t5562-http-backend-content-length.sh
@@ -46,6 +46,7 @@ ssize_b100dots() {
 }
 
 test_expect_success 'setup' '
+	test_oid_init &&
 	HTTP_CONTENT_ENCODING="identity" &&
 	export HTTP_CONTENT_ENCODING &&
 	git config http.receivepack true &&
@@ -62,8 +63,8 @@ test_expect_success 'setup' '
 	test_copy_bytes 10 <fetch_body >fetch_body.trunc &&
 	hash_next=$(git commit-tree -p HEAD -m next HEAD^{tree}) &&
 	{
-		printf "%s %s refs/heads/newbranch\\0report-status\\n" \
-			"$ZERO_OID" "$hash_next" | packetize &&
+		printf "%s %s refs/heads/newbranch\\0report-status object-format=%s\\n" \
+			"$ZERO_OID" "$hash_next" "$(test_oid algo)" | packetize &&
 		printf 0000 &&
 		echo "$hash_next" | git pack-objects --stdout
 	} >push_body &&
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
index ffb9613885..a1f5fdc9fd 100755
--- a/t/t5701-git-serve.sh
+++ b/t/t5701-git-serve.sh
@@ -5,12 +5,17 @@ test_description='test protocol v2 server commands'
 . ./test-lib.sh
 
 test_expect_success 'test capability advertisement' '
+	test_oid_cache <<-EOF &&
+	wrong_algo sha1:sha256
+	wrong_algo sha256:sha1
+	EOF
 	cat >expect <<-EOF &&
 	version 2
 	agent=git/$(git version | cut -d" " -f3)
 	ls-refs
 	fetch=shallow
 	server-option
+	object-format=$(test_oid algo)
 	0000
 	EOF
 
@@ -45,6 +50,7 @@ test_expect_success 'request invalid capability' '
 test_expect_success 'request with no command' '
 	test-tool pkt-line pack >in <<-EOF &&
 	agent=git/test
+	object-format=$(test_oid algo)
 	0000
 	EOF
 	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
@@ -54,6 +60,7 @@ test_expect_success 'request with no command' '
 test_expect_success 'request invalid command' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=foo
+	object-format=$(test_oid algo)
 	agent=git/test
 	0000
 	EOF
@@ -61,6 +68,17 @@ test_expect_success 'request invalid command' '
 	test_i18ngrep "invalid command" err
 '
 
+test_expect_success 'wrong object-format' '
+	test-tool pkt-line pack >in <<-EOF &&
+	command=fetch
+	agent=git/test
+	object-format=$(test_oid wrong_algo)
+	0000
+	EOF
+	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
+	test_i18ngrep "mismatched object format" err
+'
+
 # Test the basics of ls-refs
 #
 test_expect_success 'setup some refs and tags' '
@@ -74,6 +92,7 @@ test_expect_success 'setup some refs and tags' '
 test_expect_success 'basics of ls-refs' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
+	object-format=$(test_oid algo)
 	0000
 	EOF
 
@@ -96,6 +115,7 @@ test_expect_success 'basics of ls-refs' '
 test_expect_success 'basic ref-prefixes' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
+	object-format=$(test_oid algo)
 	0001
 	ref-prefix refs/heads/master
 	ref-prefix refs/tags/one
@@ -116,6 +136,7 @@ test_expect_success 'basic ref-prefixes' '
 test_expect_success 'refs/heads prefix' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
+	object-format=$(test_oid algo)
 	0001
 	ref-prefix refs/heads/
 	0000
@@ -136,6 +157,7 @@ test_expect_success 'refs/heads prefix' '
 test_expect_success 'peel parameter' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
+	object-format=$(test_oid algo)
 	0001
 	peel
 	ref-prefix refs/tags/
@@ -157,6 +179,7 @@ test_expect_success 'peel parameter' '
 test_expect_success 'symrefs parameter' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
+	object-format=$(test_oid algo)
 	0001
 	symrefs
 	ref-prefix refs/heads/
@@ -178,6 +201,7 @@ test_expect_success 'symrefs parameter' '
 test_expect_success 'sending server-options' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
+	object-format=$(test_oid algo)
 	server-option=hello
 	server-option=world
 	0001
@@ -200,6 +224,7 @@ test_expect_success 'unexpected lines are not allowed in fetch request' '
 
 	test-tool pkt-line pack >in <<-EOF &&
 	command=fetch
+	object-format=$(test_oid algo)
 	0001
 	this-is-not-a-command
 	0000
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index 8da65e60de..1b54c35b01 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -13,6 +13,7 @@ start_git_daemon --export-all --enable=receive-pack
 daemon_parent=$GIT_DAEMON_DOCUMENT_ROOT_PATH/parent
 
 test_expect_success 'create repo to be served by git-daemon' '
+	test_oid_init &&
 	git init "$daemon_parent" &&
 	test_commit -C "$daemon_parent" one
 '
@@ -348,7 +349,6 @@ test_expect_success 'partial fetch' '
 	rm -rf client "$(pwd)/trace" &&
 	git init client &&
 	SERVER="file://$(pwd)/server" &&
-	test_config -C client extensions.partialClone "$SERVER" &&
 
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		fetch --filter=blob:none "$SERVER" master:refs/heads/other &&
@@ -394,6 +394,7 @@ test_expect_success 'even with handcrafted request, filter does not work if not
 	# Custom request that tries to filter even though it is not advertised.
 	test-tool pkt-line pack >in <<-EOF &&
 	command=fetch
+	object-format=$(test_oid algo)
 	0001
 	want $(git -C server rev-parse master)
 	filter blob:none
@@ -795,6 +796,94 @@ test_expect_success 'when server does not send "ready", expect FLUSH' '
 	test_i18ngrep "expected no other sections to be sent after no .ready." err
 '
 
+configure_exclusion () {
+	git -C "$1" hash-object "$2" >objh &&
+	git -C "$1" pack-objects "$HTTPD_DOCUMENT_ROOT_PATH/mypack" <objh >packh &&
+	git -C "$1" config --add \
+		"uploadpack.blobpackfileuri" \
+		"$(cat objh) $(cat packh) $HTTPD_URL/dumb/mypack-$(cat packh).pack" &&
+	cat objh
+}
+
+test_expect_success 'part of packfile response provided as URI' '
+	P="$HTTPD_DOCUMENT_ROOT_PATH/http_parent" &&
+	rm -rf "$P" http_child log &&
+
+	git init "$P" &&
+	git -C "$P" config "uploadpack.allowsidebandall" "true" &&
+
+	echo my-blob >"$P/my-blob" &&
+	git -C "$P" add my-blob &&
+	echo other-blob >"$P/other-blob" &&
+	git -C "$P" add other-blob &&
+	git -C "$P" commit -m x &&
+
+	configure_exclusion "$P" my-blob >h &&
+	configure_exclusion "$P" other-blob >h2 &&
+
+	GIT_TRACE=1 GIT_TRACE_PACKET="$(pwd)/log" GIT_TEST_SIDEBAND_ALL=1 \
+	git -c protocol.version=2 \
+		-c fetch.uriprotocols=http,https \
+		clone "$HTTPD_URL/smart/http_parent" http_child &&
+
+	# Ensure that my-blob and other-blob are in separate packfiles.
+	for idx in http_child/.git/objects/pack/*.idx
+	do
+		git verify-pack --verbose $idx >out &&
+		{
+			grep "^[0-9a-f]\{16,\} " out || :
+		} >out.objectlist &&
+		if test_line_count = 1 out.objectlist
+		then
+			if grep $(cat h) out
+			then
+				>hfound
+			fi &&
+			if grep $(cat h2) out
+			then
+				>h2found
+			fi
+		fi
+	done &&
+	test -f hfound &&
+	test -f h2found &&
+
+	# Ensure that there are exactly 6 files (3 .pack and 3 .idx).
+	ls http_child/.git/objects/pack/* >filelist &&
+	test_line_count = 6 filelist
+'
+
+test_expect_success 'fetching with valid packfile URI but invalid hash fails' '
+	P="$HTTPD_DOCUMENT_ROOT_PATH/http_parent" &&
+	rm -rf "$P" http_child log &&
+
+	git init "$P" &&
+	git -C "$P" config "uploadpack.allowsidebandall" "true" &&
+
+	echo my-blob >"$P/my-blob" &&
+	git -C "$P" add my-blob &&
+	echo other-blob >"$P/other-blob" &&
+	git -C "$P" add other-blob &&
+	git -C "$P" commit -m x &&
+
+	configure_exclusion "$P" my-blob >h &&
+	# Configure a URL for other-blob. Just reuse the hash of the object as
+	# the hash of the packfile, since the hash does not matter for this
+	# test as long as it is not the hash of the pack, and it is of the
+	# expected length.
+	git -C "$P" hash-object other-blob >objh &&
+	git -C "$P" pack-objects "$HTTPD_DOCUMENT_ROOT_PATH/mypack" <objh >packh &&
+	git -C "$P" config --add \
+		"uploadpack.blobpackfileuri" \
+		"$(cat objh) $(cat objh) $HTTPD_URL/dumb/mypack-$(cat packh).pack" &&
+
+	test_must_fail env GIT_TEST_SIDEBAND_ALL=1 \
+		git -c protocol.version=2 \
+		-c fetch.uriprotocols=http,https \
+		clone "$HTTPD_URL/smart/http_parent" http_child 2>err &&
+	test_i18ngrep "pack downloaded from.*does not match expected hash" err
+'
+
 # DO NOT add non-httpd-specific tests here, because the last part of this
 # test script is only executed when httpd is available and enabled.
 
diff --git a/t/t5703-upload-pack-ref-in-want.sh b/t/t5703-upload-pack-ref-in-want.sh
index 92ad5eeec0..748282f058 100755
--- a/t/t5703-upload-pack-ref-in-want.sh
+++ b/t/t5703-upload-pack-ref-in-want.sh
@@ -27,6 +27,15 @@ check_output () {
 	test_cmp sorted_commits actual_commits
 }
 
+write_command () {
+	echo "command=$1"
+
+	if test "$(test_oid algo)" != sha1
+	then
+		echo "object-format=$(test_oid algo)"
+	fi
+}
+
 # c(o/foo) d(o/bar)
 #        \ /
 #         b   e(baz)  f(master)
@@ -65,7 +74,7 @@ test_expect_success 'config controls ref-in-want advertisement' '
 
 test_expect_success 'invalid want-ref line' '
 	test-tool pkt-line pack >in <<-EOF &&
-	command=fetch
+	$(write_command fetch)
 	0001
 	no-progress
 	want-ref refs/heads/non-existent
@@ -86,7 +95,7 @@ test_expect_success 'basic want-ref' '
 
 	oid=$(git rev-parse a) &&
 	test-tool pkt-line pack >in <<-EOF &&
-	command=fetch
+	$(write_command fetch)
 	0001
 	no-progress
 	want-ref refs/heads/master
@@ -110,7 +119,7 @@ test_expect_success 'multiple want-ref lines' '
 
 	oid=$(git rev-parse b) &&
 	test-tool pkt-line pack >in <<-EOF &&
-	command=fetch
+	$(write_command fetch)
 	0001
 	no-progress
 	want-ref refs/heads/o/foo
@@ -132,7 +141,7 @@ test_expect_success 'mix want and want-ref' '
 	git rev-parse e f >expected_commits &&
 
 	test-tool pkt-line pack >in <<-EOF &&
-	command=fetch
+	$(write_command fetch)
 	0001
 	no-progress
 	want-ref refs/heads/master
@@ -155,7 +164,7 @@ test_expect_success 'want-ref with ref we already have commit for' '
 
 	oid=$(git rev-parse c) &&
 	test-tool pkt-line pack >in <<-EOF &&
-	command=fetch
+	$(write_command fetch)
 	0001
 	no-progress
 	want-ref refs/heads/o/foo
diff --git a/t/t5704-protocol-violations.sh b/t/t5704-protocol-violations.sh
index 950cfb21fe..5c941949b9 100755
--- a/t/t5704-protocol-violations.sh
+++ b/t/t5704-protocol-violations.sh
@@ -9,6 +9,7 @@ making sure that we do not segfault or otherwise behave badly.'
 test_expect_success 'extra delim packet in v2 ls-refs args' '
 	{
 		packetize command=ls-refs &&
+		packetize "object-format=$(test_oid algo)" &&
 		printf 0001 &&
 		# protocol expects 0000 flush here
 		printf 0001
@@ -21,6 +22,7 @@ test_expect_success 'extra delim packet in v2 ls-refs args' '
 test_expect_success 'extra delim packet in v2 fetch args' '
 	{
 		packetize command=fetch &&
+		packetize "object-format=$(test_oid algo)" &&
 		printf 0001 &&
 		# protocol expects 0000 flush here
 		printf 0001
diff --git a/t/t5801/git-remote-testgit b/t/t5801/git-remote-testgit
index 6b9f0b5dc7..1544d6dc6b 100755
--- a/t/t5801/git-remote-testgit
+++ b/t/t5801/git-remote-testgit
@@ -52,9 +52,11 @@ do
 		test -n "$GIT_REMOTE_TESTGIT_SIGNED_TAGS" && echo "signed-tags"
 		test -n "$GIT_REMOTE_TESTGIT_NO_PRIVATE_UPDATE" && echo "no-private-update"
 		echo 'option'
+		echo 'object-format'
 		echo
 		;;
 	list)
+		echo ":object-format $(git rev-parse --show-object-format=storage)"
 		git for-each-ref --format='? %(refname)' 'refs/heads/' 'refs/tags/'
 		head=$(git symbolic-ref HEAD)
 		echo "@$head HEAD"
@@ -139,6 +141,10 @@ do
 			test $val = "true" && force="true" || force=
 			echo "ok"
 			;;
+		object-format)
+			test $val = "true" && object_format="true" || object_format=
+			echo "ok"
+			;;
 		*)
 			echo "unsupported"
 			;;
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 3c44af6940..8f434a0931 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -1240,6 +1240,461 @@ test_expect_success '__git_complete_fetch_refspecs - fully qualified & prefix' '
 	test_cmp expected out
 '
 
+test_expect_success 'git switch - with no options, complete local branches and unique remote branch names for DWIM logic' '
+	test_completion "git switch " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - completes refs and unique remote branches for DWIM' '
+	test_completion "git checkout " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --no-guess, complete only local branches' '
+	test_completion "git switch --no-guess " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - with GIT_COMPLETION_CHECKOUT_NO_GUESS=1, complete only local branches' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git switch " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - --guess overrides GIT_COMPLETION_CHECKOUT_NO_GUESS=1, complete local branches and unique remote names for DWIM logic' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git switch --guess " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - a later --guess overrides previous --no-guess, complete local and remote unique branches for DWIM' '
+	test_completion "git switch --no-guess --guess " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - a later --no-guess overrides previous --guess, complete only local branches' '
+	test_completion "git switch --guess --no-guess " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - with GIT_COMPLETION_NO_GUESS=1 only completes refs' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git checkout " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - --guess overrides GIT_COMPLETION_NO_GUESS=1, complete refs and unique remote branches for DWIM' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git checkout --guess " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --no-guess, only completes refs' '
+	test_completion "git checkout --no-guess " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - a later --guess overrides previous --no-guess, complete refs and unique remote branches for DWIM' '
+	test_completion "git checkout --no-guess --guess " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - a later --no-guess overrides previous --guess, complete only refs' '
+	test_completion "git checkout --guess --no-guess " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --detach, complete all references' '
+	test_completion "git switch --detach " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --detach, complete only references' '
+	test_completion "git checkout --detach " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -d, complete all references' '
+	test_completion "git switch -d " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -d, complete only references' '
+	test_completion "git checkout -d " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --track, complete only remote branches' '
+	test_completion "git switch --track " <<-\EOF
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --track, complete only remote branches' '
+	test_completion "git checkout --track " <<-\EOF
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --no-track, complete only local branch names' '
+	test_completion "git switch --no-track " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --no-track, complete only local references' '
+	test_completion "git checkout --no-track " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -c, complete all references' '
+	test_completion "git switch -c new-branch " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -C, complete all references' '
+	test_completion "git switch -C new-branch " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -c and --track, complete all references' '
+	test_completion "git switch -c new-branch --track " <<-EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -C and --track, complete all references' '
+	test_completion "git switch -C new-branch --track " <<-EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -c and --no-track, complete all references' '
+	test_completion "git switch -c new-branch --no-track " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -C and --no-track, complete all references' '
+	test_completion "git switch -C new-branch --no-track " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -b, complete all references' '
+	test_completion "git checkout -b new-branch " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -B, complete all references' '
+	test_completion "git checkout -B new-branch " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -b and --track, complete all references' '
+	test_completion "git checkout -b new-branch --track " <<-EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -B and --track, complete all references' '
+	test_completion "git checkout -B new-branch --track " <<-EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -b and --no-track, complete all references' '
+	test_completion "git checkout -b new-branch --no-track " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -B and --no-track, complete all references' '
+	test_completion "git checkout -B new-branch --no-track " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - for -c, complete local branches and unique remote branches' '
+	test_completion "git switch -c " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -C, complete local branches and unique remote branches' '
+	test_completion "git switch -C " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -c with --no-guess, complete local branches only' '
+	test_completion "git switch --no-guess -c " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -C with --no-guess, complete local branches only' '
+	test_completion "git switch --no-guess -C " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -c with --no-track, complete local branches only' '
+	test_completion "git switch --no-track -c " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -C with --no-track, complete local branches only' '
+	test_completion "git switch --no-track -C " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -b, complete local branches and unique remote branches' '
+	test_completion "git checkout -b " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -B, complete local branches and unique remote branches' '
+	test_completion "git checkout -B " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -b with --no-guess, complete local branches only' '
+	test_completion "git checkout --no-guess -b " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -B with --no-guess, complete local branches only' '
+	test_completion "git checkout --no-guess -B " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -b with --no-track, complete local branches only' '
+	test_completion "git checkout --no-track -b " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -B with --no-track, complete local branches only' '
+	test_completion "git checkout --no-track -B " <<-\EOF
+	master Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - with --orphan completes local branch names and unique remote branch names' '
+	test_completion "git switch --orphan " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - --orphan with branch already provided completes nothing else' '
+	test_completion "git switch --orphan master " <<-\EOF
+
+	EOF
+'
+
+test_expect_success 'git checkout - with --orphan completes local branch names and unique remote branch names' '
+	test_completion "git checkout --orphan " <<-\EOF
+	branch-in-other Z
+	master Z
+	master-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - --orphan with branch already provided completes local refs for a start-point' '
+	test_completion "git checkout --orphan master " <<-\EOF
+	HEAD Z
+	master Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	EOF
+'
+
 test_expect_success 'teardown after ref completion' '
 	git branch -d matching-branch &&
 	git tag -d matching-tag &&
diff --git a/t/test-lib.sh b/t/test-lib.sh
index dbc027ff26..618a7c8d5b 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -1414,6 +1414,7 @@ test_oid_init
 
 ZERO_OID=$(test_oid zero)
 OID_REGEX=$(echo $ZERO_OID | sed -e 's/0/[0-9a-f]/g')
+OIDPATH_REGEX=$(test_oid_to_path $ZERO_OID | sed -e 's/0/[0-9a-f]/g')
 EMPTY_TREE=$(test_oid empty_tree)
 EMPTY_BLOB=$(test_oid empty_blob)
 _z40=$ZERO_OID