When invoked with '--stdin-packs', pack-objects will generate a pack
which contains the objects found in the "included" packs, less any
objects from "excluded" packs.
Packs that exist in the repository but weren't specified as either
included or excluded are in practice treated like the latter, at least
in the sense that pack-objects won't include objects from those packs.
This behavior forces us to include any cruft pack(s) in a repository's
multi-pack index for the reasons described in ddee3703b3
(builtin/repack.c: add cruft packs to MIDX during geometric repack,
2022-05-20).
The full details are in ddee3703b3, but the gist is if you
have a once-unreachable object in a cruft pack which later becomes
reachable via one or more commits in a pack generated with
'--stdin-packs', you *have* to include that object in the MIDX via the
copy in the cruft pack, otherwise we cannot generate reachability
bitmaps for any commits which reach that object.
Note that the traversal here is best-effort, similar to the existing
traversal which provides name-hash hints. This means that the object
traversal may hand us back a blob that does not actually exist. We
*won't* see missing trees/commits with 'ignore_missing_links' because:
- missing commit parents are discarded at the commit traversal stage by
revision.c::process_parents()
- missing tag objects are discarded by revision.c::handle_commit()
- missing tree objects are discarded by the list-objects code in
list-objects.c::process_tree()
But we have to handle potentially-missing blobs specially by making a
separate check to ensure they exist in the repository. Failing to do so
would mean that we'd add an object to the packing list which doesn't
actually exist, rendering us unable to write out the pack.
This prepares us for new repacking behavior which will "resurrect"
objects found in cruft or otherwise unspecified packs when generating
new packs. In the context of geometric repacking, this may be used to
maintain a sequence of geometrically-repacked packs, the union of which
is closed under reachability, even in the case described earlier.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The t0450 test script verifies that builtin usage matches the synopsis
in the documentation. Adjust the builtin to match and then remove 'git
pack-objects' from the exception list.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to more easily compute delta bases among objects that appear at
the exact same path, add a --path-walk option to 'git pack-objects'.
This option will use the path-walk API instead of the object walk given
by the revision machinery. Since objects will be provided in batches
representing a common path, those objects can be tested for delta bases
immediately instead of waiting for a sort of the full object list by
name-hash. This has multiple benefits, including avoiding collisions by
name-hash.
The objects marked as UNINTERESTING are included in these batches, so we
are guaranteeing some locality to find good delta bases.
After the individual passes are done on a per-path basis, the default
name-hash is used to find other opportunistic delta bases that did not
match exactly by the full path name.
The current implementation performs delta calculations while walking
objects, which is not ideal for a few reasons. First, this will cause
the "Enumerating objects" phase to be much longer than usual. Second, it
does not take advantage of threading during the path-scoped delta
calculations. Even with this lack of threading, the path-walk option is
sometimes faster than the usual approach. Future changes will refactor
this code to allow for threading, but that complexity is deferred until
later to keep this patch as simple as possible.
This new walk is incompatible with some features and is ignored by
others:
* Object filters are not currently integrated with the path-walk API,
such as sparse-checkout or tree depth. A blobless packfile could be
integrated easily, but that is deferred for later.
* Server-focused features such as delta islands, shallow packs, and
using a bitmap index are incompatible with the path-walk API.
* The path walk API is only compatible with the --revs option, not
taking object lists or pack lists over stdin. These alternative ways
to specify the objects currently ignores the --path-walk option
without even a warning.
Future changes will create performance tests that demonstrate the power
of this approach.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All the documentation .txt files have been renamed to .adoc to help
content aware editors.
* bc/doc-adoc-not-txt:
Remove obsolete ".txt" extensions for AsciiDoc files
doc: use .adoc extension for AsciiDoc files
gitattributes: mark AsciiDoc files as LF-only
editorconfig: add .adoc extension
doc: update gitignore for .adoc extension
We presently use the ".txt" extension for our AsciiDoc files. While not
wrong, most editors do not associate this extension with AsciiDoc,
meaning that contributors don't get automatic editor functionality that
could be useful, such as syntax highlighting and prose linting.
It is much more common to use the ".adoc" extension for AsciiDoc files,
since this helps editors automatically detect files and also allows
various forges to provide rich (HTML-like) rendering. Let's do that
here, renaming all of the files and updating the includes where
relevant. Adjust the various build scripts and makefiles to use the new
extension as well.
Note that this should not result in any user-visible changes to the
documentation.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Taylor Blau