On Mon, Jun 7, 2021 at 5:26 PM Jonathan Tan <jonathantanmy@xxxxxxxxxx> wrote:
>
> This is one step towards supporting partial clone submodules.
>
> Even after this patch, we will still lack partial clone submodules
> support, primarily because a lot of Git code that accesses submodule
> objects does so by adding their object stores as alternates, meaning
> that any lazy fetches that would occur in the submodule would be done
> based on the config of the superproject, not of the submodule. This also
> prevents testing of the functionality in this patch by user-facing
> commands. So for now, test this mechanism using a test helper.
I wonder if this commit message is a good place to call out that we
also want to eventually audit codepaths using the old
has_promisor_remote() wrapper function (particularly the ones
protected by a repo == the_repository check) as well.
>
> Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx>
> ---
> Makefile | 1 +
> object-file.c | 7 ++----
> promisor-remote.c | 14 ++++++++----
> t/helper/test-partial-clone.c | 43 +++++++++++++++++++++++++++++++++++
> t/helper/test-tool.c | 1 +
> t/helper/test-tool.h | 1 +
> t/t0410-partial-clone.sh | 23 +++++++++++++++++++
> 7 files changed, 80 insertions(+), 10 deletions(-)
> create mode 100644 t/helper/test-partial-clone.c
>
> diff --git a/Makefile b/Makefile
> index c3565fc0f8..f6653bcd5e 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -725,6 +725,7 @@ TEST_BUILTINS_OBJS += test-oidmap.o
> TEST_BUILTINS_OBJS += test-online-cpus.o
> TEST_BUILTINS_OBJS += test-parse-options.o
> TEST_BUILTINS_OBJS += test-parse-pathspec-file.o
> +TEST_BUILTINS_OBJS += test-partial-clone.o
> TEST_BUILTINS_OBJS += test-path-utils.o
> TEST_BUILTINS_OBJS += test-pcre2-config.o
> TEST_BUILTINS_OBJS += test-pkt-line.o
> diff --git a/object-file.c b/object-file.c
> index f233b440b2..ebf273e9e7 100644
> --- a/object-file.c
> +++ b/object-file.c
> @@ -1570,15 +1570,12 @@ static int do_oid_object_info_extended(struct repository *r,
> }
>
> /* Check if it is a missing object */
> - if (fetch_if_missing && has_promisor_remote() &&
> - !already_retried && r == the_repository &&
> + if (fetch_if_missing && repo_has_promisor_remote(r) &&
> + !already_retried &&
> !(flags & OBJECT_INFO_SKIP_FETCH_OBJECT)) {
> /*
> * TODO Investigate checking promisor_remote_get_direct()
> * TODO return value and stopping on error here.
> - * TODO Pass a repository struct through
> - * promisor_remote_get_direct(), such that arbitrary
> - * repositories work.
> */
> promisor_remote_get_direct(r, real, 1);
> already_retried = 1;
> diff --git a/promisor-remote.c b/promisor-remote.c
> index e1e1f7e93a..1491374d65 100644
> --- a/promisor-remote.c
> +++ b/promisor-remote.c
> @@ -11,7 +11,8 @@ struct promisor_remote_config {
> struct promisor_remote **promisors_tail;
> };
>
> -static int fetch_objects(const char *remote_name,
> +static int fetch_objects(struct repository *repo,
> + const char *remote_name,
> const struct object_id *oids,
> int oid_nr)
> {
> @@ -21,6 +22,11 @@ static int fetch_objects(const char *remote_name,
>
> child.git_cmd = 1;
> child.in = -1;
> + if (repo != the_repository) {
> + prepare_other_repo_env(&child.env_array);
> + strvec_pushf(&child.env_array, "%s=%s", GIT_DIR_ENVIRONMENT,
> + repo->gitdir);
> + }
> strvec_pushl(&child.args, "-c", "fetch.negotiationAlgorithm=noop",
> "fetch", remote_name, "--no-tags",
> "--no-write-fetch-head", "--recurse-submodules=no",
> @@ -154,7 +160,7 @@ static void promisor_remote_init(struct repository *r)
> xcalloc(sizeof(*r->promisor_remote_config), 1);
> config->promisors_tail = &config->promisors;
>
> - git_config(promisor_remote_config, config);
> + repo_config(r, promisor_remote_config, config);
>
> if (config->repository_format_partial_clone) {
> struct promisor_remote *o, *previous;
> @@ -252,10 +258,8 @@ int promisor_remote_get_direct(struct repository *repo,
>
> promisor_remote_init(repo);
>
> - if (repo != the_repository)
> - BUG("only the_repository is supported for now");
> for (r = repo->promisor_remote_config->promisors; r; r = r->next) {
> - if (fetch_objects(r->name, remaining_oids, remaining_nr) < 0) {
> + if (fetch_objects(repo, r->name, remaining_oids, remaining_nr) < 0) {
> if (remaining_nr == 1)
> continue;
> remaining_nr = remove_fetched_oids(repo, &remaining_oids,
> diff --git a/t/helper/test-partial-clone.c b/t/helper/test-partial-clone.c
> new file mode 100644
> index 0000000000..3f102cfddd
> --- /dev/null
> +++ b/t/helper/test-partial-clone.c
> @@ -0,0 +1,43 @@
> +#include "cache.h"
> +#include "test-tool.h"
> +#include "repository.h"
> +#include "object-store.h"
> +
> +/*
> + * Prints the size of the object corresponding to the given hash in a specific
> + * gitdir. This is similar to "git -C gitdir cat-file -s", except that this
> + * exercises the code that accesses the object of an arbitrary repository that
> + * is not the_repository. ("git -C gitdir" makes it so that the_repository is
> + * the one in gitdir.)
> + */
> +static void object_info(const char *gitdir, const char *oid_hex)
> +{
> + struct repository r;
> + struct object_id oid;
> + unsigned long size;
> + struct object_info oi = {.sizep = &size};
> + const char *p;
> +
> + if (repo_init(&r, gitdir, NULL))
> + die("could not init repo");
> + if (parse_oid_hex(oid_hex, &oid, &p))
> + die("could not parse oid");
> + if (oid_object_info_extended(&r, &oid, &oi, 0))
> + die("could not obtain object info");
> + printf("%d\n", (int) size);
> +}
> +
> +int cmd__partial_clone(int argc, const char **argv)
> +{
> + setup_git_directory();
> +
> + if (argc < 4)
> + die("too few arguments");
> +
> + if (!strcmp(argv[1], "object-info"))
> + object_info(argv[2], argv[3]);
> + else
> + die("invalid argument '%s'", argv[1]);
> +
> + return 0;
> +}
> diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
> index c5bd0c6d4c..b21e8f1519 100644
> --- a/t/helper/test-tool.c
> +++ b/t/helper/test-tool.c
> @@ -46,6 +46,7 @@ static struct test_cmd cmds[] = {
> { "online-cpus", cmd__online_cpus },
> { "parse-options", cmd__parse_options },
> { "parse-pathspec-file", cmd__parse_pathspec_file },
> + { "partial-clone", cmd__partial_clone },
> { "path-utils", cmd__path_utils },
> { "pcre2-config", cmd__pcre2_config },
> { "pkt-line", cmd__pkt_line },
> diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
> index e8069a3b22..f845ced4b3 100644
> --- a/t/helper/test-tool.h
> +++ b/t/helper/test-tool.h
> @@ -35,6 +35,7 @@ int cmd__oidmap(int argc, const char **argv);
> int cmd__online_cpus(int argc, const char **argv);
> int cmd__parse_options(int argc, const char **argv);
> int cmd__parse_pathspec_file(int argc, const char** argv);
> +int cmd__partial_clone(int argc, const char **argv);
> int cmd__path_utils(int argc, const char **argv);
> int cmd__pcre2_config(int argc, const char **argv);
> int cmd__pkt_line(int argc, const char **argv);
> diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
> index 584a039b85..a211a66c67 100755
> --- a/t/t0410-partial-clone.sh
> +++ b/t/t0410-partial-clone.sh
> @@ -604,6 +604,29 @@ test_expect_success 'do not fetch when checking existence of tree we construct o
> git -C repo cherry-pick side1
> '
>
> +test_expect_success 'lazy-fetch when accessing object not in the_repository' '
> + rm -rf full partial.git &&
> + test_create_repo full &&
> + test_commit -C full create-a-file file.txt &&
> +
> + test_config -C full uploadpack.allowfilter 1 &&
> + test_config -C full uploadpack.allowanysha1inwant 1 &&
> + git clone --filter=blob:none --bare "file://$(pwd)/full" partial.git &&
> + FILE_HASH=$(git -C full rev-parse HEAD:file.txt) &&
> +
> + # Sanity check that the file is missing
> + git -C partial.git rev-list --objects --missing=print HEAD >out &&
> + grep "[?]$FILE_HASH" out &&
> +
> + git -C full cat-file -s "$FILE_HASH" >expect &&
> + test-tool partial-clone object-info partial.git "$FILE_HASH" >actual &&
> + test_cmp expect actual &&
> +
> + # Sanity check that the file is now present
> + git -C partial.git rev-list --objects --missing=print HEAD >out &&
> + ! grep "[?]$FILE_HASH" out
> +'
> +
> . "$TEST_DIRECTORY"/lib-httpd.sh
> start_httpd
>
> --
> 2.32.0.rc1.229.g3e70b5a671-goog
>
