Subject: [PATCH 0/6] cat-file: add remote-object-info to batch-command

From: Eric Ju <[email-masked]>
Date: Fri, 28 Jun 2024 15:04:57 -0400

This is a continuation of Calvin Wan's ([email-masked])
patch series [PATCH v5 0/6] cat-file: add --batch-command remote-object-info command at [1].

Sometimes it is useful to get 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)"[2].
This patch series implement the client option for it.

This patch series add 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 is v2, but does not have
object-info capability, the entire object is fetched and the
relevant object info is returned.

A few questions open for discussions please:

1. In the current implementation, if a user puts `remote-object-info` in protocol v1,
   `cat-file --batch-command` will die. Which way do we prefer? "error and exit (i.e. die)"
   or "warn and wait for new command".

2. Right now, only the size is supported. If the batch command format
   contains objectsize:disk or deltabase, it will die. The question
   is about objecttype. In the current implementation, it will die too.
   But dying on objecttype breaks the default format. We have changed the
   default format to %(objectname) %(objectsize) when remote-object-info is used.
   Any suggestions on this approach?

[1] https://lore.kernel.org/git/[email-masked]/#t
[2] https://git.kernel.org/pub/scm/git/git.git/commit/?id=a2ba162cda2acc171c3e36acbbc854792b093cb7

Calvin Wan (5):
  fetch-pack: refactor packet writing
  fetch-pack: move fetch initialization
  serve: advertise object-info feature
  transport: add client support for object-info
  cat-file: add remote-object-info to batch-command

Eric Ju (1):
  cat-file: add declaration of variable i inside its for loop

 Documentation/git-cat-file.txt         |  22 +-
 builtin/cat-file.c                     | 240 ++++++++++----
 fetch-pack.c                           |  48 ++-
 fetch-pack.h                           |  10 +
 object-file.c                          |  11 +
 object-store-ll.h                      |   3 +
 serve.c                                |   4 +-
 t/t1017-cat-file-remote-object-info.sh | 412 +++++++++++++++++++++++++
 transport-helper.c                     |   8 +-
 transport.c                            | 102 +++++-
 transport.h                            |  11 +
 11 files changed, 785 insertions(+), 86 deletions(-)
 create mode 100755 t/t1017-cat-file-remote-object-info.sh

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2.45.2