From: Pablo Sabater Date: Mon, 08 Jun 2026 10:14:23 GMT Subject: [PATCH GSoC RFC v12 00/12] cat-file: add remote-object-info to batch-command Message-ID: <20260608-ps-eric-work-rebase-v12-0-5338b766e658@gmail.com> In-Reply-To: <20250221190451.12536-1-eric.peijian@gmail.com> This path series is a continuation of Eric Ju's (eric.peijian@gmail.com) and Calvin Wan's (calvinwan@google.com) patch series [1] and [2] respectively. Sometimes it is beneficial to retrieve information about an object without having to download it completely. The server logic for retrieving size has already been implemented and merged in "a2ba162cda (object-info: support for retrieving object info, 2021-04-20)"[3]. This patch series implement the client option for it. Eric's series adds the `remote-object-info` command to `cat-file --batch-command`. This command allows the client to make an object-info command request to a server that supports protocol v2. If the server uses protocol v2 but does not support the object-info capability, `cat-file --batch-command` will die. If a user attempts to use `remote-object-info` with protocol v1, `cat-file --batch-command` will die. Currently, only the size (%(objectsize)) is supported end to end in this implementation. The type (%(objecttype)) is known by the client's allow-list and request path but is not supported on the server side nor the response parsing. A follow up series will add full end-to-end support for %(objecttype). The default format for remote-object-info is set to %(objectname) %(objectsize). Once %(objecttype) is supported, the default format will be unified accordingly. If the batch command format includes unsupported fields such as %(objecttype), %(objectsize:disk), or %(deltabase), the command will return empty strings for each unsupported field. This series completes Eric's work mainly with the refactor of the validation of the placeholder with an allow-list that filters what the client asks with what the server is capable of provide following Jeff King's idea [4]. I have a question for the design: 1. If the format includes unsupported fields such as %(objecttype) or %(deltabase) it currently returns an empty string for each unsupported field, this follows what for-each-ref does with known but inapplicable atoms. However future placeholders that will be implemented: %(rest), %(objectmode) can return empty strings. How should we differentiate "unsupported" vs "no data". Eric proposed to use a placeholder like "???" [5]. [1]: https://lore.kernel.org/git/20250221190451.12536-1-eric.peijian@gmail.com/ [2]: https://lore.kernel.org/git/20220728230210.2952731-1-calvinwan@google.com/#t [3]: https://git.kernel.org/pub/scm/git/git.git/commit/?id=a2ba162cda2acc171c3e36acbbc854792b093cb7 [4]: https://lore.kernel.org/git/20250313060250.GH94015@coredump.intra.peff.net/ [5]: https://lore.kernel.org/git/CAN2LT1D3d=yMYVhBjpj5PvyjfTVjwqcFPNViuCJ=f49YbCZuJg@mail.gmail.com/ Changes since v11: - Rebased onto current master. - Added fetch-object-info.c to meson.build. - Added t1017-cat-file-remote-object-info.sh to t/meson.build. - Fixed style feedback from v10. - Replaced strstr() validation with a dynamic allow-list in expand_atom() based on server-advertised capabilities, filtering unsupported options in fetch_object_info() before sending. - Unsupported placeholders return empty strings instead of die(). - Initialize data->type to OBJ_BAD with NULL check on type_name(). - Moved global variables to local scope in parse_cmd_remote_object_info. - Decoupled batch_object_write() from sizep so output is always produced. - Added remote_atom_map[] for protocol-to-atom name mapping. - Included "type" in the client request path for forward-compatibility. - Fixed memory leak of data->name in transport-helper disconnect. - Changed error message "not our ref" to "server does not recognize object". - Split fetch-pack refactoring into two commits (move + refactor). - Updated caveats documentation and tests. Signed-off-by: Pablo Sabater --- Calvin Wan (3): fetch-pack: move fetch initialization serve: advertise object-info feature transport: add client support for object-info Eric Ju (4): git-compat-util: add strtoul_ul() with error handling cat-file: add declaration of variable i inside its for loop t1006: split test utility functions into new "lib-cat-file.sh" cat-file: add remote-object-info to batch-command Pablo Sabater (5): transport-helper: fix memory leak of helper on disconnect fetch-pack: move function to connect.c connect: refactor packet writing cat-file: validate remote atoms with allow_list cat-file: make remote-object-info allow-list dynamic Documentation/git-cat-file.adoc | 25 +- Makefile | 1 + builtin/cat-file.c | 191 ++++++++- connect.c | 34 ++ connect.h | 8 + fetch-object-info.c | 93 +++++ fetch-object-info.h | 22 ++ fetch-pack.c | 51 +-- fetch-pack.h | 2 + git-compat-util.h | 20 + meson.build | 1 + object-file.c | 10 + odb.h | 3 + serve.c | 5 +- t/lib-cat-file.sh | 16 + t/meson.build | 1 + t/t1006-cat-file.sh | 13 +- t/t1017-cat-file-remote-object-info.sh | 684 +++++++++++++++++++++++++++++++++ transport-helper.c | 13 +- transport.c | 28 +- transport.h | 11 + 21 files changed, 1158 insertions(+), 74 deletions(-) --- base-commit: 9ac3f193c05c2237e2b14ebaa1149e9fc8a1abe0 change-id: 20260608-ps-eric-work-rebase-b73ae84ba671 Best regards, -- Pablo Sabater