Drop unused parameters from functions.
* jk/drop-unused-parameters:
diff-lib: drop unused index argument from get_stat_data()
ref-filter: drop unused parameters from email_atom_option_parser()
pack-bitmap: drop unused parameters from select_pseudo_merges()
pack-bitmap: load writer config from repository parameter
refs: drop some unused parameters from create_symref_lock()
We created a useless pseudo-merge reachability bitmap that is about
0 commits, and attempted to include commits that are not in packs,
which made no sense. These bugs have been corrected.
* tb/pseudo-merge-bitmap-fixes:
pseudo-merge.c: ensure pseudo-merge groups are closed
pseudo-merge.c: do not generate empty pseudo-merge commits
t/t5333-pseudo-merge-bitmaps.sh: demonstrate empty pseudo-merge groups
pack-bitmap-write.c: select pseudo-merges even for small bitmaps
pack-bitmap: drop redundant args from `bitmap_writer_finish()`
pack-bitmap: drop redundant args from `bitmap_writer_build()`
pack-bitmap: drop redundant args from `bitmap_writer_build_type_index()`
pack-bitmap: initialize `bitmap_writer_init()` with packing_data
We take the array of indexed_commits (and its length), but there's no
need. The selection is based on ref reachability, not the linearized set
of commits we're packing.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In bitmap_writer_init(), we take a repository parameter but ever look at
it. Most of the initialization here is independent of the repository,
but we do load some config. So let's pass the repo we get down to
load_pseudo_merges_from_config(), which in turn can use repo_config(),
rather than depending on the_repository via git_config().
The outcome is the same, since all callers pass in the_repository
anyway. But it takes us a step closer to getting rid of the global, and
as a bonus it silences an unused parameter warning.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When generating pseudo-merge bitmaps, it's possible that concurrent
reference updates may reveal some pseudo-merge candidates which reach
objects that are not contained in the bitmap's pack or pseudo-pack
order (in the case of MIDX bitmaps).
The latter case is relatively easy to demonstrate: if we generate a MIDX
bitmap with only half of the repository packed, then the unpacked
contents are not part of the MIDX's object order.
If we happen to select one or more commit(s) from the unpacked portion
of the repository for inclusion in a pseudo-merge, we'll get the
following message when trying to generate its bitmap:
$ git multi-pack-index write --bitmap
[...]
Selecting pseudo-merge commits: 100% (1/1), done.
warning: Failed to write bitmap index. Packfile doesn't have full closure (object ... is missing)
Building bitmaps: 50% (1/2), done.
error: could not write multi-pack bitmap
, and the attempted bitmap write will fail, leaving the repository
without a current bitmap.
Rectify this by ensuring that the commits which are pseudo-merge
candidates can only be so if they appear somewhere in the packing order.
This is sufficient, since we know that the original packing order is
closed under reachability, so if a commit appears in that list as a
potential pseudo-merge candidate, we know that everything reachable from
it also appears in the list (and thus the candidate is a good one).
Noticed-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous commit demonstrated it is possible to generate empty
pseudo-merge commits, which is not useful as such pseudo-merges carry no
information.
Ensure that we only generate non-empty groups by not pushing a new
commit onto the bitmap_writer when that commit has no parents.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a parameter to each_ref_fn so that callers to the ref APIs
that use this function as a callback can have acess to the
unresolved value of a symbolic ref.
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A CPP macro USE_THE_REPOSITORY_VARIABLE is introduced to help
transition the codebase to rely less on the availability of the
singleton the_repository instance.
* ps/use-the-repository:
hex: guard declarations with `USE_THE_REPOSITORY_VARIABLE`
t/helper: remove dependency on `the_repository` in "proc-receive"
t/helper: fix segfault in "oid-array" command without repository
t/helper: use correct object hash in partial-clone helper
compat/fsmonitor: fix socket path in networked SHA256 repos
replace-object: use hash algorithm from passed-in repository
protocol-caps: use hash algorithm from passed-in repository
oidset: pass hash algorithm when parsing file
http-fetch: don't crash when parsing packfile without a repo
hash-ll: merge with "hash.h"
refs: avoid include cycle with "repository.h"
global: introduce `USE_THE_REPOSITORY_VARIABLE` macro
hash: require hash algorithm in `empty_tree_oid_hex()`
hash: require hash algorithm in `is_empty_{blob,tree}_oid()`
hash: make `is_null_oid()` independent of `the_repository`
hash: convert `oidcmp()` and `oideq()` to compare whole hash
global: ensure that object IDs are always padded
hash: require hash algorithm in `oidread()` and `oidclr()`
hash: require hash algorithm in `hasheq()`, `hashcmp()` and `hashclr()`
hash: drop (mostly) unused `is_empty_{blob,tree}_sha1()` functions
The pseudo-merge reachability bitmap to help more efficient storage
of the reachability bitmap in a repository with too many refs has
been added.
* tb/pseudo-merge-reachability-bitmap: (26 commits)
pack-bitmap.c: ensure pseudo-merge offset reads are bounded
Documentation/technical/bitmap-format.txt: add missing position table
t/perf: implement performance tests for pseudo-merge bitmaps
pseudo-merge: implement support for finding existing merges
ewah: `bitmap_equals_ewah()`
pack-bitmap: extra trace2 information
pack-bitmap.c: use pseudo-merges during traversal
t/test-lib-functions.sh: support `--notick` in `test_commit_bulk()`
pack-bitmap: implement test helpers for pseudo-merge
ewah: implement `ewah_bitmap_popcount()`
pseudo-merge: implement support for reading pseudo-merge commits
pack-bitmap.c: read pseudo-merge extension
pseudo-merge: scaffolding for reads
pack-bitmap: extract `read_bitmap()` function
pack-bitmap-write.c: write pseudo-merge table
pseudo-merge: implement support for selecting pseudo-merge commits
config: introduce `git_config_double()`
pack-bitmap: make `bitmap_writer_push_bitmapped_commit()` public
pack-bitmap: implement `bitmap_writer_has_bitmapped_object_id()`
pack-bitmap-write: support storing pseudo-merge commits
...
This patch implements support for reusing existing pseudo-merge commits
when writing bitmaps when there is an existing pseudo-merge bitmap which
has exactly the same set of parents as one that we are about to write.
Note that unstable pseudo-merges are likely to change between
consecutive repacks, and so are generally poor candidates for reuse.
However, stable pseudo-merges (see the configuration option
'bitmapPseudoMerge.<name>.stableThreshold') are by definition unlikely
to change between runs (as they represent long-running branches).
Because there is no index from a *set* of pseudo-merge parents to a
matching pseudo-merge bitmap, we have to construct the bitmap
corresponding to the set of parents for each pending pseudo-merge commit
and see if a matching bitmap exists.
This is technically quadratic in the number of pseudo-merges, but is OK
in practice for a couple of reasons:
- non-matching pseudo-merge bitmaps are rejected quickly as soon as
they differ in a single bit
- already-matched pseudo-merge bitmaps are discarded from subsequent
rounds of search
- the number of pseudo-merges is generally small, even for large
repositories
In order to do this, implement (a) a function that finds a matching
pseudo-merge given some uncompressed bitset describing its parents, (b)
a function that computes the bitset of parents for a given pseudo-merge
commit, and (c) call that function before computing the set of reachable
objects for some pending pseudo-merge.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement the basic API for reading pseudo-merge bitmaps, which consists
of four basic functions:
- pseudo_merge_bitmap()
- use_pseudo_merge()
- apply_pseudo_merges_for_commit()
- cascade_pseudo_merges()
These functions are all documented in pseudo-merge.h, but their rough
descriptions are as follows:
- pseudo_merge_bitmap() reads and inflates the objects EWAH bitmap for
a given pseudo-merge
- use_pseudo_merge() does the same as pseudo_merge_bitmap(), but on
the commits EWAH bitmap, not the objects bitmap
- apply_pseudo_merges_for_commit() applies all satisfied pseudo-merge
commits for a given result set, and cascades any yet-unsatisfied
pseudo-merges if any were applied in the previous step
- cascade_pseudo_merges() applies all pseudo-merges which are
satisfied but have not been previously applied, repeating this
process until no more pseudo-merges can be applied
The core of the API is the latter two functions, which are responsible
for applying pseudo-merges during the object traversal implemented in
the pack-bitmap machinery.
The other two functions (pseudo_merge_bitmap(), and use_pseudo_merge())
are low-level ways to interact with the pseudo-merge machinery, which
will be useful in future commits.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement scaffolding within the new pseudo-merge compilation unit
necessary to use the pseudo-merge API from within the pack-bitmap.c
machinery.
The core of this scaffolding is two-fold:
- The `pseudo_merge` structure itself, which represents an individual
pseudo-merge bitmap. It has fields for both bitmaps, as well as
metadata about its position within the memory-mapped region, and
a few extra bits indicating whether or not it is satisfied, and
which bitmaps(s, if any) have been read, since they are initialized
lazily.
- The `pseudo_merge_map` structure, which holds an array of
pseudo_merges, as well as a pointer to the memory-mapped region
containing the pseudo-merge serialization from within a .bitmap
file.
Note that the `bitmap_index` structure is defined statically within the
pack-bitmap.o compilation unit, so we can't take in a `struct
bitmap_index *`. Instead, wrap the primary components necessary to read
the pseudo-merges in this new structure to avoid exposing the
implementation details of the `bitmap_index` structure.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach the new pseudo-merge machinery how to select non-bitmapped commits
for inclusion in different pseudo-merge group(s) based on a handful of
criteria.
Note that the selected pseudo-merge commits aren't actually used or
written anywhere yet. This will be done in the following commit.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a new (empty) header file to contain the implementation for
selecting, reading, and applying pseudo-merge bitmaps.
For now this header and its corresponding implementation are left
empty, but they will evolve over the course of subsequent commit(s).
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
