git-commit-vandalism/t/t5544-pack-objects-hook.sh
Glen Choo 5b3c650777 config: learn git_protected_config()
`uploadpack.packObjectsHook` is the only 'protected configuration only'
variable today, but we've noted that `safe.directory` and the upcoming
`safe.bareRepository` should also be 'protected configuration only'. So,
for consistency, we'd like to have a single implementation for protected
configuration.

The primary constraints are:

1. Reading from protected configuration should be fast. Nearly all "git"
   commands inside a bare repository will read both `safe.directory` and
   `safe.bareRepository`, so we cannot afford to be slow.

2. Protected configuration must be readable when the gitdir is not
   known. `safe.directory` and `safe.bareRepository` both affect
   repository discovery and the gitdir is not known at that point [1].

The chosen implementation in this commit is to read protected
configuration and cache the values in a global configset. This is
similar to the caching behavior we get with the_repository->config.

Introduce git_protected_config(), which reads protected configuration
and caches them in the global configset protected_config. Then, refactor
`uploadpack.packObjectsHook` to use git_protected_config().

The protected configuration functions are named similarly to their
non-protected counterparts, e.g. git_protected_config_check_init() vs
git_config_check_init().

In light of constraint 1, this implementation can still be improved.
git_protected_config() iterates through every variable in
protected_config, which is wasteful, but it makes the conversion simple
because it matches existing patterns. We will likely implement constant
time lookup functions for protected configuration in a future series
(such functions already exist for non-protected configuration, i.e.
repo_config_get_*()).

An alternative that avoids introducing another configset is to continue
to read all config using git_config(), but only accept values that have
the correct config scope [2]. This technically fulfills constraint 2,
because git_config() simply ignores the local and worktree config when
the gitdir is not known. However, this would read incomplete config into
the_repository->config, which would need to be reset when the gitdir is
known and git_config() needs to read the local and worktree config.
Resetting the_repository->config might be reasonable while we only have
these 'protected configuration only' variables, but it's not clear
whether this extends well to future variables.

[1] In this case, we do have a candidate gitdir though, so with a little
refactoring, it might be possible to provide a gitdir.
[2] This is how `uploadpack.packObjectsHook` was implemented prior to
this commit.

Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-07-14 15:08:29 -07:00

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#!/bin/sh
test_description='test custom script in place of pack-objects'
. ./test-lib.sh
test_expect_success 'create some history to fetch' '
test_commit one &&
test_commit two
'
test_expect_success 'create debugging hook script' '
write_script .git/hook <<-\EOF
echo >&2 "hook running"
echo "$*" >hook.args
cat >hook.stdin
"$@" <hook.stdin >hook.stdout
cat hook.stdout
EOF
'
clear_hook_results () {
rm -rf .git/hook.* dst.git
}
test_expect_success 'hook runs via global config' '
clear_hook_results &&
test_config_global uploadpack.packObjectsHook ./hook &&
git clone --no-local . dst.git 2>stderr &&
grep "hook running" stderr
'
test_expect_success 'hook outputs are sane' '
# check that we recorded a usable pack
git index-pack --stdin <.git/hook.stdout &&
# check that we recorded args and stdin. We do not check
# the full argument list or the exact pack contents, as it would make
# the test brittle. So just sanity check that we could replay
# the packing procedure.
grep "^git" .git/hook.args &&
$(cat .git/hook.args) <.git/hook.stdin >replay
'
test_expect_success 'hook runs from -c config' '
clear_hook_results &&
git clone --no-local \
-u "git -c uploadpack.packObjectsHook=./hook upload-pack" \
. dst.git 2>stderr &&
grep "hook running" stderr
'
test_expect_success 'hook does not run from repo config' '
clear_hook_results &&
test_config uploadpack.packObjectsHook "./hook" &&
git clone --no-local . dst.git 2>stderr &&
! grep "hook running" stderr &&
test_path_is_missing .git/hook.args &&
test_path_is_missing .git/hook.stdin &&
test_path_is_missing .git/hook.stdout &&
# check that global config is used instead
test_config_global uploadpack.packObjectsHook ./hook &&
git clone --no-local . dst2.git 2>stderr &&
grep "hook running" stderr
'
test_expect_success 'hook works with partial clone' '
clear_hook_results &&
test_config_global uploadpack.packObjectsHook ./hook &&
test_config_global uploadpack.allowFilter true &&
git clone --bare --no-local --filter=blob:none . dst.git &&
git -C dst.git rev-list --objects --missing=allow-any --no-object-names --all >objects &&
git -C dst.git cat-file --batch-check="%(objecttype)" <objects >types &&
! grep blob types
'
test_done