chore(3p/git): Unvendor git and track patches instead r/2903

This was vendored a long time ago under the expectation that keeping
it in sync with cgit would be easier this way, but it has proven not
to be a big issue.

On the other hand, a vendored copy of git is an annoying maintenance
burden. It is much easier to rebase the single (dottime) patch that we
have.

This removes the vendored copy of git and instead passes the git
source code to cgit via `pkgs.srcOnly`, which includes the applied
patch so that cgit can continue rendering dottime.

Change-Id: If31f62dea7ce688fd1b9050204e9378019775f2b

1 files changed, 0 insertions, 109 deletions

diff --git a/third_party/git/Documentation/technical/multi-pack-index.txt b/third_party/git/Documentation/technical/multi-pack-index.txt
deleted file mode 100644
index 4e7631437a58..000000000000
--- a/third_party/git/Documentation/technical/multi-pack-index.txt
+++ /dev/null
@@ -1,109 +0,0 @@
-Multi-Pack-Index (MIDX) Design Notes
-====================================
-
-The Git object directory contains a 'pack' directory containing
-packfiles (with suffix ".pack") and pack-indexes (with suffix
-".idx"). The pack-indexes provide a way to lookup objects and
-navigate to their offset within the pack, but these must come
-in pairs with the packfiles. This pairing depends on the file
-names, as the pack-index differs only in suffix with its pack-
-file. While the pack-indexes provide fast lookup per packfile,
-this performance degrades as the number of packfiles increases,
-because abbreviations need to inspect every packfile and we are
-more likely to have a miss on our most-recently-used packfile.
-For some large repositories, repacking into a single packfile
-is not feasible due to storage space or excessive repack times.
-
-The multi-pack-index (MIDX for short) stores a list of objects
-and their offsets into multiple packfiles. It contains:
-
-- A list of packfile names.
-- A sorted list of object IDs.
-- A list of metadata for the ith object ID including:
-  - A value j referring to the jth packfile.
-  - An offset within the jth packfile for the object.
-- If large offsets are required, we use another list of large
-  offsets similar to version 2 pack-indexes.
-
-Thus, we can provide O(log N) lookup time for any number
-of packfiles.
-
-Design Details
---------------
-
-- The MIDX is stored in a file named 'multi-pack-index' in the
-  .git/objects/pack directory. This could be stored in the pack
-  directory of an alternate. It refers only to packfiles in that
-  same directory.
-
-- The core.multiPackIndex config setting must be on to consume MIDX files.
-
-- The file format includes parameters for the object ID hash
-  function, so a future change of hash algorithm does not require
-  a change in format.
-
-- The MIDX keeps only one record per object ID. If an object appears
-  in multiple packfiles, then the MIDX selects the copy in the most-
-  recently modified packfile.
-
-- If there exist packfiles in the pack directory not registered in
-  the MIDX, then those packfiles are loaded into the `packed_git`
-  list and `packed_git_mru` cache.
-
-- The pack-indexes (.idx files) remain in the pack directory so we
-  can delete the MIDX file, set core.midx to false, or downgrade
-  without any loss of information.
-
-- The MIDX file format uses a chunk-based approach (similar to the
-  commit-graph file) that allows optional data to be added.
-
-Future Work
------------
-
-- Add a 'verify' subcommand to the 'git midx' builtin to verify the
-  contents of the multi-pack-index file match the offsets listed in
-  the corresponding pack-indexes.
-
-- The multi-pack-index allows many packfiles, especially in a context
-  where repacking is expensive (such as a very large repo), or
-  unexpected maintenance time is unacceptable (such as a high-demand
-  build machine). However, the multi-pack-index needs to be rewritten
-  in full every time. We can extend the format to be incremental, so
-  writes are fast. By storing a small "tip" multi-pack-index that
-  points to large "base" MIDX files, we can keep writes fast while
-  still reducing the number of binary searches required for object
-  lookups.
-
-- The reachability bitmap is currently paired directly with a single
-  packfile, using the pack-order as the object order to hopefully
-  compress the bitmaps well using run-length encoding. This could be
-  extended to pair a reachability bitmap with a multi-pack-index. If
-  the multi-pack-index is extended to store a "stable object order"
-  (a function Order(hash) = integer that is constant for a given hash,
-  even as the multi-pack-index is updated) then a reachability bitmap
-  could point to a multi-pack-index and be updated independently.
-
-- Packfiles can be marked as "special" using empty files that share
-  the initial name but replace ".pack" with ".keep" or ".promisor".
-  We can add an optional chunk of data to the multi-pack-index that
-  records flags of information about the packfiles. This allows new
-  states, such as 'repacked' or 'redeltified', that can help with
-  pack maintenance in a multi-pack environment. It may also be
-  helpful to organize packfiles by object type (commit, tree, blob,
-  etc.) and use this metadata to help that maintenance.
-
-- The partial clone feature records special "promisor" packs that
-  may point to objects that are not stored locally, but available
-  on request to a server. The multi-pack-index does not currently
-  track these promisor packs.
-
-Related Links
--------------
-[0] https://bugs.chromium.org/p/git/issues/detail?id=6
-    Chromium work item for: Multi-Pack Index (MIDX)
-
-[1] https://lore.kernel.org/git/20180107181459.222909-1-dstolee@microsoft.com/
-    An earlier RFC for the multi-pack-index feature
-
-[2] https://lore.kernel.org/git/alpine.DEB.2.20.1803091557510.23109@alexmv-linux/
-    Git Merge 2018 Contributor's summit notes (includes discussion of MIDX)