git-commit-vandalism/t/t5617-clone-submodules-remote.sh
Josh Steadmon f05da2b48b clone, submodule: pass partial clone filters to submodules
When cloning a repo with a --filter and with --recurse-submodules
enabled, the partial clone filter only applies to the top-level repo.
This can lead to unexpected bandwidth and disk usage for projects which
include large submodules. For example, a user might wish to make a
partial clone of Gerrit and would run:
`git clone --recurse-submodules --filter=blob:5k https://gerrit.googlesource.com/gerrit`.
However, only the superproject would be a partial clone; all the
submodules would have all blobs downloaded regardless of their size.
With this change, the same filter can also be applied to submodules,
meaning the expected bandwidth and disk savings apply consistently.

To avoid changing default behavior, add a new clone flag,
`--also-filter-submodules`. When this is set along with `--filter` and
`--recurse-submodules`, the filter spec is passed along to git-submodule
and git-submodule--helper, such that submodule clones also have the
filter applied.

This applies the same filter to the superproject and all submodules.
Users who need to customize the filter per-submodule would need to clone
with `--no-recurse-submodules` and then manually initialize each
submodule with the proper filter.

Applying filters to submodules should be safe thanks to Jonathan Tan's
recent work [1, 2, 3] eliminating the use of alternates as a method of
accessing submodule objects, so any submodule object access now triggers
a lazy fetch from the submodule's promisor remote if the accessed object
is missing. This patch is a reworked version of [4], which was created
prior to Jonathan Tan's work.

[1]: 8721e2e (Merge branch 'jt/partial-clone-submodule-1', 2021-07-16)
[2]: 11e5d0a (Merge branch 'jt/grep-wo-submodule-odb-as-alternate',
	2021-09-20)
[3]: 162a13b (Merge branch 'jt/no-abuse-alternate-odb-for-submodules',
	2021-10-25)
[4]: https://lore.kernel.org/git/52bf9d45b8e2b72ff32aa773f2415bf7b2b86da2.1563322192.git.steadmon@google.com/

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-09 15:38:36 -08:00

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#!/bin/sh
test_description='Test cloning repos with submodules using remote-tracking branches'
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
. ./test-lib.sh
pwd=$(pwd)
test_expect_success 'setup' '
git checkout -b main &&
test_commit commit1 &&
mkdir sub &&
(
cd sub &&
git init &&
test_commit subcommit1 &&
git tag sub_when_added_to_super &&
git branch other
) &&
git submodule add "file://$pwd/sub" sub &&
git commit -m "add submodule" &&
(
cd sub &&
test_commit subcommit2
)
'
# bare clone giving "srv.bare" for use as our server.
test_expect_success 'setup bare clone for server' '
git clone --bare "file://$(pwd)/." srv.bare &&
git -C srv.bare config --local uploadpack.allowfilter 1 &&
git -C srv.bare config --local uploadpack.allowanysha1inwant 1
'
test_expect_success 'clone with --no-remote-submodules' '
test_when_finished "rm -rf super_clone" &&
git clone --recurse-submodules --no-remote-submodules "file://$pwd/." super_clone &&
(
cd super_clone/sub &&
git diff --exit-code sub_when_added_to_super
)
'
test_expect_success 'clone with --remote-submodules' '
test_when_finished "rm -rf super_clone" &&
git clone --recurse-submodules --remote-submodules "file://$pwd/." super_clone &&
(
cd super_clone/sub &&
git diff --exit-code remotes/origin/main
)
'
test_expect_success 'check the default is --no-remote-submodules' '
test_when_finished "rm -rf super_clone" &&
git clone --recurse-submodules "file://$pwd/." super_clone &&
(
cd super_clone/sub &&
git diff --exit-code sub_when_added_to_super
)
'
test_expect_success 'clone with --single-branch' '
test_when_finished "rm -rf super_clone" &&
git clone --recurse-submodules --single-branch "file://$pwd/." super_clone &&
(
cd super_clone/sub &&
git rev-parse --verify origin/main &&
test_must_fail git rev-parse --verify origin/other
)
'
# do basic partial clone from "srv.bare"
# confirm partial clone was registered in the local config for super and sub.
test_expect_success 'clone with --filter' '
git clone --recurse-submodules \
--filter blob:none --also-filter-submodules \
"file://$pwd/srv.bare" super_clone &&
test_cmp_config -C super_clone true remote.origin.promisor &&
test_cmp_config -C super_clone blob:none remote.origin.partialclonefilter &&
test_cmp_config -C super_clone/sub true remote.origin.promisor &&
test_cmp_config -C super_clone/sub blob:none remote.origin.partialclonefilter
'
# check that clone.filterSubmodules works (--also-filter-submodules can be
# omitted)
test_expect_success 'filters applied with clone.filterSubmodules' '
test_config_global clone.filterSubmodules true &&
git clone --recurse-submodules --filter blob:none \
"file://$pwd/srv.bare" super_clone2 &&
test_cmp_config -C super_clone2 true remote.origin.promisor &&
test_cmp_config -C super_clone2 blob:none remote.origin.partialclonefilter &&
test_cmp_config -C super_clone2/sub true remote.origin.promisor &&
test_cmp_config -C super_clone2/sub blob:none remote.origin.partialclonefilter
'
test_expect_success '--no-also-filter-submodules overrides clone.filterSubmodules=true' '
test_config_global clone.filterSubmodules true &&
git clone --recurse-submodules --filter blob:none \
--no-also-filter-submodules \
"file://$pwd/srv.bare" super_clone3 &&
test_cmp_config -C super_clone3 true remote.origin.promisor &&
test_cmp_config -C super_clone3 blob:none remote.origin.partialclonefilter &&
test_cmp_config -C super_clone3/sub false --default false remote.origin.promisor
'
test_done