The idea of the magic value "ac4f2ee" in this test is to make the
reworded commit `collide2` have the same shortened ID as the commit
`collide3`.
To port the same idea to the SHA-256 version of Git, we therefore need
another magic value that causes the same collision, but this time with
the SHA-256 version of the commit IDs.
In this patch, we add code guarded by `GIT_TEST_FIND_COLLIDER` to do
exactly that. Essentially, a large number of integers is appended to the
commit message "collide2" to find such a collision. To make it easier to
find such a collision, we reduce the number of digits to 4.
As the tests are no longer dependent on SHA-1, we also rename their
titles to talk about "commit IDs" instead of "SHA-1s".
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When computing the fanout length, let's use test_oid to look up the
hexadecimal size of the hash in question instead of hard-coding a value.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use $ZERO_OID to make the test hash independent.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The bloom filter code relies on reading object IDs using parse_oid_hex.
In order to make that work with an appropriate size, we need to have
initialized the repository's hash algorithm. Since the values we're
processing depend on the repository in use, let's set up the repository
when we run the test helper.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 2.28-rc0, we corrected a bug that some repository extensions are
honored by mistake even in a version 0 repositories (these
configuration variables in extensions.* namespace were supposed to
have special meaning in repositories whose version numbers are 1 or
higher), but this was a bit too big a change.
* jn/v0-with-extensions-fix:
repository: allow repository format upgrade with extensions
Revert "check_repository_format_gently(): refuse extensions for old repositories"
Now that we officially permit repository extensions in repository
format v0, permit upgrading a repository with extensions from v0 to v1
as well.
For example, this means a repository where the user has set
"extensions.preciousObjects" can use "git fetch --filter=blob:none
origin" to upgrade the repository to use v1 and the partial clone
extension.
To avoid mistakes, continue to forbid repository format upgrades in v0
repositories with an unrecognized extension. This way, a v0 user
using a misspelled extension field gets a chance to correct the
mistake before updating to the less forgiving v1 format.
While we're here, make the error message for failure to upgrade the
repository format a bit shorter, and present it as an error, not a
warning.
Reported-by: Huan Huan Chen <huanhuanchen@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 14c7fa269e42df4133edd9ae7763b678ed6594cd.
The core.repositoryFormatVersion field was introduced in ab9cb76f661
(Repository format version check., 2005-11-25), providing a welcome
bit of forward compatibility, thanks to some welcome analysis by
Martin Atukunda. The semantics are simple: a repository with
core.repositoryFormatVersion set to 0 should be comprehensible by all
Git implementations in active use; and Git implementations should
error out early instead of trying to act on Git repositories with
higher core.repositoryFormatVersion values representing new formats
that they do not understand.
A new repository format did not need to be defined until 00a09d57eb8
(introduce "extensions" form of core.repositoryformatversion,
2015-06-23). This provided a finer-grained extension mechanism for
Git repositories. In a repository with core.repositoryFormatVersion
set to 1, Git implementations can act on "extensions.*" settings that
modify how a repository is interpreted. In repository format version
1, unrecognized extensions settings cause Git to error out.
What happens if a user sets an extension setting but forgets to
increase the repository format version to 1? The extension settings
were still recognized in that case; worse, unrecognized extensions
settings do *not* cause Git to error out. So combining repository
format version 0 with extensions settings produces in some sense the
worst of both worlds.
To improve that situation, since 14c7fa269e4
(check_repository_format_gently(): refuse extensions for old
repositories, 2020-06-05) Git instead ignores extensions in v0 mode.
This way, v0 repositories get the historical (pre-2015) behavior and
maintain compatibility with Git implementations that do not know about
the v1 format. Unfortunately, users had been using this sort of
configuration and this behavior change came to many as a surprise:
- users of "git config --worktree" that had followed its advice
to enable extensions.worktreeConfig (without also increasing the
repository format version) would find their worktree configuration
no longer taking effect
- tools such as copybara[*] that had set extensions.partialClone in
existing repositories (without also increasing the repository format
version) would find that setting no longer taking effect
The behavior introduced in 14c7fa269e4 might be a good behavior if we
were traveling back in time to 2015, but we're far too late. For some
reason I thought that it was what had been originally implemented and
that it had regressed. Apologies for not doing my research when
14c7fa269e4 was under development.
Let's return to the behavior we've had since 2015: always act on
extensions.* settings, regardless of repository format version. While
we're here, include some tests to describe the effect on the "upgrade
repository version" code path.
[*] ca76c0b1e1
Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix to the code to produce progress bar, which is new in the
upcoming release.
* tb/commit-graph-no-check-oids:
commit-graph: fix "Collecting commits from input" progress line
The code to produce progress output from "git commit-graph --write"
had a few breakages, which have been fixed.
* sg/commit-graph-progress-fix:
commit-graph: fix "Writing out commit graph" progress counter
commit-graph: fix progress of reachable commits
When an aliased command, whose output is piped to a pager by git,
gets killed by a signal, the pager got into a funny state, which
has been corrected (again).
* ta/wait-on-aliased-commands-upon-signal:
Wait for child on signal death for aliases to externals
Wait for child on signal death for aliases to builtins
To display a progress line while reading commits from standard input
and looking them up, 5b6653e523 (builtin/commit-graph.c: dereference
tags in builtin, 2020-05-13) should have added a pair of
start_delayed_progress() and stop_progress() calls around the loop
reading stdin. Alas, the stop_progress() call ended up at the wrong
place, after write_commit_graph(), which does all the commit-graph
computation and writing, and has several progress lines of its own.
Consequently, that new
Collecting commits from input: 1234
progress line is overwritten by the first progress line shown by
write_commit_graph(), and its final "done" line is shown last, after
everything is finished:
$ { sleep 3 ; git rev-list -3 HEAD ; sleep 1 ; } | ~/src/git/git commit-graph write --stdin-commits
Expanding reachable commits in commit graph: 873402, done.
Writing out commit graph in 4 passes: 100% (3493608/3493608), done.
Collecting commits from input: 3, done.
Furthermore, that stop_progress() call was added after the 'cleanup'
label, where that loop reading stdin jumps in case of an error. In
case of invalid input this then results in the "done" line shown after
the error message:
$ { sleep 3 ; git rev-list -3 HEAD ; echo junk ; } | ~/src/git/git commit-graph write --stdin-commits
error: unexpected non-hex object ID: junk
Collecting commits from input: 3, done.
Move that stop_progress() call to the right place.
While at it, drop the unnecessary 'if (progress)' condition protecting
the stop_progress() call, because that function is prepared to handle
a NULL progress struct.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The description of `git diff` goes through several different invocations
(numbering added by me):
1. git diff [<options>] [--] [<path>...]
2. git diff [<options>] --no-index [--] <path> <path>
3. git diff [<options>] --cached [<commit>] [--] [<path>...]
4. git diff [<options>] <commit> [--] [<path>...]
5. git diff [<options>] <commit> <commit> [--] [<path>...]
6. git diff [<options>] <commit>..<commit> [--] [<path>...]
7. git diff [<options>] <commit> <commit>... <commit> [--] [<path>...]
8. git diff [<options>] <commit>...<commit> [--] [<path>...]
It then goes on to say that "all of the <commit> in the above
description, except in the last two forms that use '..' notations, can
be any <tree>". The "last two" actually refers to 6 and 8. This got out
of sync in commit b7e10b2ca2 ("Documentation: usage for diff combined
commits", 2020-06-12) which added item 7 to the mix.
As a further complication, after b7e10b2ca2 we also have some potential
confusion around "the '..' notation". The "..[.]" in items 6 and 8 are
part of the rev notation, whereas the "..." in item 7 is manpage
language for "one or more".
Move item 6 down, i.e., to between 7 and 8, to restore the ordering.
Because 6 refers to 5 ("synonymous to the previous form") we need to
tweak the language a bit.
An added bonus of this commit is that we're trying to steer users away
from `git diff <commit>..<commit>` and moving it further down probably
doesn't hurt.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit b7e10b2ca2 ("Documentation: usage for diff combined commits",
2020-06-12) modified the synopsis by adding an optional "[<commit>...]"
to
'git diff' [<options>] <commit> <commit> [--] [<path>...]
to effectively add
'git diff' [<options>] <commit> <commit>... <commit> [--] [<path>...]
as another valid invocation. Which makes sense.
Further down, in the description, it left the existing entry for
'git diff' [<options>] <commit> <commit> [--] [<path>...]
intact and added a new entry on
'git diff' [<options>] <commit> [<commit>...] <commit> [--] [<path>...]
where it says that "[t]his form is to view the results of a merge
commit" and details how "the first listed commit must be the merge
itself". But one possible instantiation of this form is `git diff
<commit> <commit>` for which the added text doesn't really apply.
Remove the brackets so that we lose this overlap between the two
descriptions. We can still use the more compact representation in the
synopsis.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git checkout" failed to catch an error from fstat() after updating
a path in the working tree.
* mt/entry-fstat-fallback-fix:
entry: check for fstat() errors after checkout
"fetch.writeCommitGraph" was enabled when "feature.experimental" is
asked for, but it was found to be a bit too risky even for bold
folks in its current shape. The configuration has been ejected, at
least for now, from the "experimental" feature set.
* jn/eject-fetch-write-commit-graph-out-of-experimental:
experimental: default to fetch.writeCommitGraph=false
When "fetch.writeCommitGraph" configuration is set in a shallow
repository and a fetch moves the shallow boundary, we wrote out
broken commit-graph files that do not match the reality, which has
been corrected.
* tb/fix-persistent-shallow:
commit.c: don't persist substituted parents when unshallowing
Recent update to "git diff" meant as a code clean-up introduced a
bug in its error handling code, which has been corrected.
* ct/diff-with-merge-base-clarification:
diff: check for merge bases before assigning sym->base
"git log -Lx,y:path --before=date" lost track of where the range
should be because it didn't take the changes made by the youngest
commits that are omitted from the output into account.
* rs/line-log-until:
revision: disable min_age optimization with line-log
"git send-email --in-reply-to=<msg>" did not use the In-Reply-To:
header with the value given from the command line, and let it be
overridden by the value on In-Reply-To: header in the messages
being sent out (if exists).
* ra/send-email-in-reply-to-from-command-line-wins:
send-email: restore --in-reply-to superseding behavior
The command line completion support (in contrib/) used to be
prepared to work with "set -u" but recent changes got a bit more
sloppy. This has been corrected.
* vs/completion-with-set-u:
completion: nounset mode fixes
We don't give a "::" for the list separator, but just a single ":". This
ends up rendering literally, "--apply: Use applying strategies ...". As
a follow-on error, the list continuation, "+", also ends up rendering
literally (because we don't have a list).
This was introduced in 52eb738d6b ("rebase: add an --am option",
2020-02-15) and survived the rename in 10cdb9f38a ("rebase: rename the
two primary rebase backends", 2020-02-15).
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
76ffbca71a (commit-graph: write Bloom filters to commit graph file,
2020-04-06) added two delayed progress lines to writing the Bloom
filter index and data chunk. This is wrong, because a single common
progress is used while writing all chunks, which is not updated while
writing these two new chunks, resulting in incomplete-looking "done"
lines:
Expanding reachable commits in commit graph: 888679, done.
Computing commit changed paths Bloom filters: 100% (888678/888678), done.
Writing out commit graph in 6 passes: 66% (3554712/5332068), done.
Use the common 'struct progress' instance while writing the Bloom
filter chunks as well.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To display a progress line while iterating over all refs,
d335ce8f24 (commit-graph.c: show progress of finding reachable
commits, 2020-05-13) should have added a pair of
start_delayed_progress() and stop_progress() calls around a
for_each_ref() invocation. Alas, the stop_progress() call ended up at
the wrong place, after write_commit_graph(), which does all the
commit-graph computation and writing, and has several progress lines
of its own. Consequently, that new
Collecting referenced commits: 123
progress line is overwritten by the first progress line shown by
write_commit_graph(), and its final "done" line is shown last, after
everything is finished:
Expanding reachable commits in commit graph: 344786, done.
Computing commit changed paths Bloom filters: 100% (344786/344786), done.
Collecting referenced commits: 154, done.
Move that stop_progress() call to the right place.
While at it, drop the unnecessary 'if (data.progress)' condition
protecting the stop_progress() call, because that function is prepared
to handle a NULL progress struct.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 11179eb311 ("entry.c: check if file exists after checkout",
2017-10-05) we started checking the result of the lstat() call done
after writing a file, to avoid writing garbage to the corresponding
cache entry. However, the code skips calling lstat() if it's possible
to use fstat() when it still has the file descriptor open. And when
calling fstat() we don't do the same error checking. To fix that, let
the callers of fstat_output() know when fstat() fails. In this case,
write_entry() will try to use lstat() and properly report an error if
that fails as well.
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The fetch.writeCommitGraph feature makes fetches write out a commit
graph file for the newly downloaded pack on fetch. This improves the
performance of various commands that would perform a revision walk and
eventually ought to be the default for everyone. To prepare for that
future, it's enabled by default for users that set
feature.experimental=true to experience such future defaults.
Alas, for --unshallow fetches from a shallow clone it runs into a
snag: by the time Git has fetched the new objects and is writing a
commit graph, it has performed a revision walk and r->parsed_objects
contains information about the shallow boundary from *before* the
fetch. The commit graph writing code is careful to avoid writing a
commit graph file in shallow repositories, but the new state is not
shallow, and the result is that from that point on, commands like "git
log" make use of a newly written commit graph file representing a
fictional history with the old shallow boundary.
We could fix this by making the commit graph writing code more careful
to avoid writing a commit graph that could have used any grafts or
shallow state, but it is possible that there are other pieces of
mutated state that fetch's commit graph writing code may be relying
on. So disable it in the feature.experimental configuration.
Google developers have been running in this configuration (by setting
fetch.writeCommitGraph=false in the system config) to work around this
bug since it was discovered in April. Once the fix lands, we'll
enable fetch.writeCommitGraph=true again to give it some early testing
before rolling out to a wider audience.
In other words:
- this patch only affects behavior with feature.experimental=true
- it makes feature.experimental match the configuration Google has
been using for the last few months, meaning it would leave users in
a better tested state than without it
- this should improve testing for other features guarded by
feature.experimental, by making feature.experimental safer to use
Reported-by: Jay Conrod <jayconrod@google.com>
Helped-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 37b9dcabfc (shallow.c: use '{commit,rollback}_shallow_file',
2020-04-22), Git knows how to reset stat-validity checks for the
$GIT_DIR/shallow file, allowing it to change between a shallow and
non-shallow state in the same process (e.g., in the case of 'git fetch
--unshallow').
However, when $GIT_DIR/shallow changes, Git does not alter or remove any
grafts (nor substituted parents) in memory.
This comes up in a "git fetch --unshallow" with fetch.writeCommitGraph
set to true. Ordinarily in a shallow repository (and before 37b9dcabfc,
even in this case), commit_graph_compatible() would return false,
indicating that the repository should not be used to write a
commit-graphs (since commit-graph files cannot represent a shallow
history). But since 37b9dcabfc, in an --unshallow operation that check
succeeds.
Thus even though the repository isn't shallow any longer (that is, we
have all of the objects), the in-core representation of those objects
still has munged parents at the shallow boundaries. When the
commit-graph write proceeds, we use the incorrect parentage, producing
wrong results.
There are two ways for a user to work around this: either (1) set
'fetch.writeCommitGraph' to 'false', or (2) drop the commit-graph after
unshallowing.
One way to fix this would be to reset the parsed object pool entirely
(flushing the cache and thus preventing subsequent reads from modifying
their parents) after unshallowing. That would produce a problem when
callers have a now-stale reference to the old pool, and so this patch
implements a different approach. Instead, attach a new bit to the pool,
'substituted_parent', which indicates if the repository *ever* stored a
commit which had its parents modified (i.e., the shallow boundary
prior to unshallowing).
This bit needs to be sticky because all reads subsequent to modifying a
commit's parents are unreliable when unshallowing. Modify the check in
'commit_graph_compatible' to take this bit into account, and correctly
avoid generating commit-graphs in this case, thus solving the bug.
Helped-by: Derrick Stolee <dstolee@microsoft.com>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Reported-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In symdiff_prepare(), we iterate over the set of parsed objects to pick
out any symmetric differences, including the left, right, and base
elements. We assign the results into pointers in a "struct symdiff", and
then complain if we didn't find a base, like so:
sym->left = rev->pending.objects[lpos].name;
sym->right = rev->pending.objects[rpos].name;
sym->base = rev->pending.objects[basepos].name;
if (basecount == 0)
die(_("%s...%s: no merge base"), sym->left, sym->right);
But the least lines are backwards. If basecount is 0, then basepos will
be -1, and we will access memory outside of the pending array. This
isn't usually that big a deal, since we don't do anything besides a
single pointer-sized read before exiting anyway, but it does violate the
C standard, and of course memory-checking tools like ASan complain.
Let's put the basecount check first. Note that we haveto split it from
the other assignments, since the die() relies on sym->left and
sym->right having been assigned (this isn't strictly necessary, but is
easier to read than dereferencing the pending array again).
Reported-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we are running an alias to an external command, we want to wait for
that process to exit even after receiving ^C which normally kills the
git process. This is useful when the process is ignoring SIGINT (which
e.g. pagers often do), and then we don't want it to be killed.
Having an alias which invokes a pager is probably not common, but it can
be useful e.g. if you have an alias to a git command which uses a
subshell as one of the arguments (in which case you have to use an
external command, not an alias to a builtin).
This patch is similar to the previous commit, but the previous commit
fixed this only for aliases to builtins, while this commit does the same
for aliases to external commands. In addition to waiting after clean
like the previous commit, this also enables cleaning the child (that was
already enabled for aliases to builtins before the previous commit),
because wait_after_clean relies on it. Lastly, while the previous commit
fixed a regression, I don't think this has ever worked properly.
Signed-off-by: Trygve Aaberge <trygveaa@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When you hit ^C all the processes in the tree receives it. When a git
command uses a pager, git ignores this and waits until the pager quits.
However, when using an alias there is an additional process in the tree
which didn't ignore the signal. That caused it to exit which in turn
caused the pager to exit. This fixes that for aliases to builtins.
This was originally fixed in 46df6906 (execv_dashed_external: wait
for child on signal death, 2017-01-06), but was broken by ee4512ed
(trace2: create new combined trace facility, 2019-02-22) and then
b9140840 (git: avoid calling aliased builtins via their dashed form,
2019-07-29).
Signed-off-by: Trygve Aaberge <trygveaa@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The effort to avoid using test_must_fail on non-git command continues.
* dl/test-must-fail-fixes-5:
lib-submodule-update: pass 'test_must_fail' as an argument
lib-submodule-update: prepend "git" to $command
lib-submodule-update: consolidate --recurse-submodules
lib-submodule-update: add space after function name
"git fast-export --anonymize" learned to take customized mapping to
allow its users to tweak its output more usable for debugging.
* jk/fast-export-anonym-alt:
fast-export: use local array to store anonymized oid
fast-export: anonymize "master" refname
fast-export: allow seeding the anonymized mapping
fast-export: add a "data" callback parameter to anonymize_str()
fast-export: move global "idents" anonymize hashmap into function
fast-export: use a flex array to store anonymized entries
fast-export: stop storing lengths in anonymized hashmaps
fast-export: tighten anonymize_mem() interface to handle only strings
fast-export: store anonymized oids as hex strings
fast-export: use xmemdupz() for anonymizing oids
t9351: derive anonymized tree checks from original repo
"git difftool" has trouble dealing with paths added to the index
with the intent-to-add bit.
* js/diff-files-i-t-a-fix-for-difftool:
difftool -d: ensure that intent-to-add files are handled correctly
diff-files --raw: show correct post-image of intent-to-add files
The name of the primary branch in existing repositories, and the
default name used for the first branch in newly created
repositories, is made configurable, so that we can eventually wean
ourselves off of the hardcoded 'master'.
* js/default-branch-name:
contrib: subtree: adjust test to change in fmt-merge-msg
testsvn: respect `init.defaultBranch`
remote: use the configured default branch name when appropriate
clone: use configured default branch name when appropriate
init: allow setting the default for the initial branch name via the config
init: allow specifying the initial branch name for the new repository
docs: add missing diamond brackets
submodule: fall back to remote's HEAD for missing remote.<name>.branch
send-pack/transport-helper: avoid mentioning a particular branch
fmt-merge-msg: stop treating `master` specially
The code to push changes over "dumb" HTTP had a bad interaction
with the commit reachability code due to incorrect allocation of
object flag bits, which has been corrected.
* bc/http-push-flagsfix:
http-push: ensure unforced pushes fail when data would be lost
The documentation and some tests have been adjusted for the recent
renaming of "pu" branch to "seen".
* js/pu-to-seen:
tests: reference `seen` wherever `pu` was referenced
docs: adjust the technical overview for the rename `pu` -> `seen`
docs: adjust for the recent rename of `pu` to `seen`
Add "git prune" to the completion (in contrib/), which could be
typed by end-users from the command line.
* jl/complete-git-prune:
bash-completion: add git-prune into bash completion
API cleanup for get_worktrees()
* es/get-worktrees-unsort:
worktree: drop get_worktrees() unused 'flags' argument
worktree: drop get_worktrees() special-purpose sorting option
CVS/SVN interface have been prepared for SHA-256 transition
* bc/sha-256-cvs-svn-updates:
git-cvsexportcommit: port to SHA-256
git-cvsimport: port to SHA-256
git-cvsserver: port to SHA-256
git-svn: set the OID length based on hash algorithm
perl: make SVN code hash independent
perl: make Git::IndexInfo work with SHA-256
perl: create and switch variables for hash constants
t/lib-git-svn: make hash size independent
t9101: make hash independent
t9104: make hash size independent
t9100: make test work with SHA-256
t9108: make test hash independent
t9168: make test hash independent
t9109: make test hash independent
A few fields in "struct commit" that do not have to always be
present have been moved to commit slabs.
* ak/commit-graph-to-slab:
commit-graph: minimize commit_graph_data_slab access
commit: move members graph_pos, generation to a slab
commit-graph: introduce commit_graph_data_slab
object: drop parsed_object_pool->commit_count
