[PATCH 0/9] Bundle URIs IV: advertise over protocol v2

This is based on the recent master batch that included ds/bundle-uri-....

Now that git clone --bundle-uri can download a bundle list from a plaintex file in config format, we can use the same set of key-value pairs to advertise a bundle list over protocol v2. At the end of this series:

 1. A server can advertise bundles when uploadPack.advertiseBundleURIs is
    enabled. The bundle list comes from the server's local config,
    specifically the bundle.* namespace.
 2. A client can notice a server's bundle-uri advertisement and request the
    bundle list if transfer.bundleURI is enabled. The bundles are downloaded
    as if the list was advertised from the --bundle-uri option.

Many patches in this series were adapted from Ævar's v2 RFC [1]. He is retained as author and I added myself as co-author only if the modifications were significant.

[1] https://lore.kernel.org/git/RFC-patch-v2-01.13-2fc87ce092b-20220311T155841Z-avarab@gmail.com/

 * Patches 1-5 are mostly taken from [1], again with mostly minor updates.
   The one major difference is the packet line format being a single
   key=value format instead of a sequence of pairs. This also means that
   Patch 4 is entirely new since it feeds these pairs directly from the
   server's config.

 * Patches 6-9 finish off the ability for the client to notice the
   capability, request the values, and download bundles before continuing
   with the rest of the download.

One thing that is not handled here but could be handled in a future change is to disconnect from the origin Git server while downloading the bundle URIs, then reconnecting afterwards. This does not make any difference for HTTPS, but SSH may benefit from the reduced connection time. The git clone --bundle-uri option did not suffer from this because the bundles are downloaded before the server connection begins.

After this series, there is one more before the original scope of the plan is complete: using creation tokens as a heuristic. See [2] for the RFC version of those patches.

[2] https://github.com/derrickstolee/git/pull/22

Thanks,

 * Stolee

Derrick Stolee (5):
  bundle-uri: serve bundle.* keys from config
  strbuf: reintroduce strbuf_parent_directory()
  bundle-uri: allow relative URLs in bundle lists
  bundle-uri: download bundles from an advertised list
  clone: unbundle the advertised bundles

Ævar Arnfjörð Bjarmason (4):
  protocol v2: add server-side "bundle-uri" skeleton
  bundle-uri client: add minimal NOOP client
  bundle-uri client: add helper for testing server
  bundle-uri client: add boolean transfer.bundleURI setting

 Documentation/config/transfer.txt      |   6 +
 Documentation/gitprotocol-v2.txt       | 193 +++++++++++++++++++++
 builtin/clone.c                        |  23 +++
 bundle-uri.c                           |  91 +++++++++-
 bundle-uri.h                           |  27 +++
 connect.c                              |  47 +++++
 remote.h                               |   5 +
 serve.c                                |   6 +
 strbuf.c                               |   9 +
 strbuf.h                               |   7 +
 t/helper/test-bundle-uri.c             |  48 ++++++
 t/lib-t5730-protocol-v2-bundle-uri.sh  | 229 +++++++++++++++++++++++++
 t/t5601-clone.sh                       |  59 +++++++
 t/t5701-git-serve.sh                   |  40 ++++-
 t/t5730-protocol-v2-bundle-uri-file.sh |  36 ++++
 t/t5731-protocol-v2-bundle-uri-git.sh  |  17 ++
 t/t5732-protocol-v2-bundle-uri-http.sh |  17 ++
 t/t5750-bundle-uri-parse.sh            |  54 ++++++
 transport-helper.c                     |  13 ++
 transport-internal.h                   |   7 +
 transport.c                            |  87 ++++++++++
 transport.h                            |  23 +++
 22 files changed, 1042 insertions(+), 2 deletions(-)
 create mode 100644 t/lib-t5730-protocol-v2-bundle-uri.sh
 create mode 100755 t/t5730-protocol-v2-bundle-uri-file.sh
 create mode 100755 t/t5731-protocol-v2-bundle-uri-git.sh
 create mode 100755 t/t5732-protocol-v2-bundle-uri-http.sh

base-commit: c03801e19cb8ab36e9c0d17ff3d5e0c3b0f24193
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1400%2Fderrickstolee%2Fbundle-redo%2Fadvertise-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1400/derrickstolee/bundle-redo/advertise-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1400