"git pull --rebase" ignored the rebase.autostash configuration
variable when the remote history is a descendant of our history,
which has been corrected.
* pb/pull-rebase-autostash-fix:
pull --rebase: honor rebase.autostash when fast-forwarding
Remove mistaken right square brackets from "git-diff"
usage string. Make the usage string conform to "git-diff"
documentation (Documentation/git-diff.txt).
Signed-off-by: Shaoxuan Yuan <shaoxuan.yuan02@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Doing diffs for merges are special; they should typically avoid history
simplification. For example, with
git log --diff-merges=first-parent -- path
the default history simplification would remove merge commits from
consideration if the file "path" matched the second parent. That is
counter to what the user wants when looking for first-parent diffs.
Similar comments can be made for --diff-merges=separate (which diffs
against both parents) and --diff-merges=remerge (which diffs against a
remerge of the merge commit).
However, history simplification still makes sense if not doing diffing
merges, and it also makes sense for the combined and dense-combined
forms of diffing merges (because both of those are defined to only show
a diff when the merge result at the relevant paths differs from *both*
parents).
So, for separate, first-parent, and remerge styles of diff-merges, turn
off history simplification.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A recursive merge involves merging the merge bases of the two branches
being merged. Such an inner merge can itself generate conflict notices.
While such notices may be useful when initially trying to create a
merge, they seem to just be noise when investigating merges later with
--remerge-diff. (Especially when both sides of the outer merge resolved
the conflict the same way leading to no overall conflict.) Remove them.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Conflicts such as modify/delete, rename/rename, or file/directory are
not representable via content conflict markers, and the normal output
messages notifying users about these were dropped with --remerge-diff.
While we don't want these messages randomly shown before the commit
and diff headers, we do want them to still be shown; include them as
part of the diff headers instead.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When additional headers are provided, we need to
* add diff_filepairs to diff_queued_diff for each paths in the
additional headers map which, unless that path is part of
another diff_filepair already found in diff_queued_diff
* format the headers (colorization, line_prefix for --graph)
* make sure the various codepaths that attempt to return early
if there are "no changes" take into account the headers that
need to be shown.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When users run
git show --remerge-diff $MERGE_COMMIT
or
git log -p --remerge-diff ...
stdout is not an appropriate location to dump conflict messages, but we
do want to provide them to users. We will include them in the diff
headers instead...but for that to work, we need for any multiline
messages to replace newlines with both a newline and a space. Add a new
flag to signal when we want these messages modified in such a fashion,
and use it in path_msg() to modify these messages this way. Also, allow
a special prefix to be specified for these headers.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
path_msg() has the ability to mark messages as omittable, designed for
remerge-diff where we'll instead be showing conflict messages as diff
headers for a subsequent diff. While all these messages are very useful
when trying to create a merge initially, early use with the
--remerge-diff feature (the only user of this omittable conflict message
capability), suggests that the particular messages marked in this commit
are just noise when trying to see what changes users made to create a
merge commit. Mark them as omittable.
Note that there were already a few messages marked as omittable in
merge-ort when doing a remerge-diff, because the development of
--remerge-diff preceded the upstreaming of merge-ort and I was trying to
ensure merge-ort could handle all the necessary requirements. See
commit c5a6f65527 ("merge-ort: add modify/delete handling and delayed
output processing", 2020-12-03) for the initial details. For some
examples of already-marked-as-omittable messages, see either
"Auto-merging <path>" or some of the submodule update hints. This
commit just adds two more messages that should also be omittable.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of immediately printing ll-merge warnings to stderr, we save
them in our output strbuf. Besides allowing us to move these warnings
to a special file for --remerge-diff, this has two other benefits for
regular merges done by merge-ort:
* The deferral of messages ensures we can print all messages about
any given path together (merge-recursive was known to sometimes
intersperse messages about other paths, particularly when renames
were involved).
* The deferral of messages means we can avoid printing spurious
conflict messages when we just end up aborting due to local user
modifications in the way. (In contrast to merge-recursive.c which
prematurely checks for local modifications in the way via
unpack_trees() and gets the check wrong both in terms of false
positives and false negatives relative to renames, merge-ort does
not perform the local modifications in the way check until the
checkout() step after the full merge has been computed.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since some callers may want to send warning messages to somewhere other
than stdout/stderr, stop printing "warning: Cannot merge binary files"
from ll-merge and instead modify the return status of ll_merge() to
indicate when a merge of binary files has occurred. Message printing
probably does not belong in a "low-level merge" anyway.
This commit continues printing the message as-is, just from the callers
instead of within ll_merge(). Future changes will start handling the
message differently in the merge-ort codepath.
There was one special case here: the callers in rerere.c do NOT check
for and print such a message; since those code paths explicitly skip
over binary files, there is no reason to check for a return status of
LL_MERGE_BINARY_CONFLICT or print the related message.
Note that my methodology included first modifying ll_merge() to return
a struct, so that the compiler would catch all the callers for me and
ensure I had modified all of them. After modifying all of them, I then
changed the struct to an enum.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The --remerge-diff option will need to create new blobs and trees
representing the "automatic merge" state. If one is traversing a
long project history, one can easily get hundreds of thousands of
loose objects generated during `log --remerge-diff`. However, none of
those loose objects are needed after we have completed our diff
operation; they can be summarily deleted.
Add a new helper function to tmp_objdir to discard all the contained
objects, and call it after each merge is handled.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When this option is specified, we remerge all (two parent) merge commits
and diff the actual merge commit to the automatically created version,
in order to show how users removed conflict markers, resolved the
different conflict versions, and potentially added new changes outside
of conflict regions in order to resolve semantic merge problems (or,
possibly, just to hide other random changes).
This capability works by creating a temporary object directory and
marking it as the primary object store. This makes it so that any blobs
or trees created during the automatic merge are easily removable
afterwards by just deleting all objects from the temporary object
directory.
There are a few ways that this implementation is suboptimal:
* `log --remerge-diff` becomes slow, because the temporary object
directory can fill with many loose objects while running
* the log output can be muddied with misplaced "warning: cannot merge
binary files" messages, since ll-merge.c unconditionally writes those
messages to stderr while running instead of allowing callers to
manage them.
* important conflict and warning messages are simply dropped; thus for
conflicts like modify/delete or rename/rename or file/directory which
are not representable with content conflict markers, there may be no
way for a user of --remerge-diff to know that there had been a
conflict which was resolved (and which possibly motivated other
changes in the merge commit).
* when fixing the previous issue, note that some unimportant conflict
and warning messages might start being included. We should instead
make sure these remain dropped.
Subsequent commits will address these issues.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Give the traditional default fetch.negotiationAlgorithm the name
'consecutive'. Also allow a choice of 'default' to have Git decide
between the choices (currently, picking 'skipping' if
feature.experimental is true and 'consecutive' otherwise). Update the
documentation accordingly.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit af3a67de01 ("negotiator: unknown fetch.negotiationAlgorithm
should error out", 2018-08-01), error handling for an unknown
fetch.negotiationAlgorithm was added with the code die()ing. This was
also added to the documentation for the fetch.negotiationAlgorithm
option, to make it explicit that the code would die on unknown values.
This behavior was lost with commit aaf633c2ad ("repo-settings: create
feature.experimental setting", 2019-08-13). Restore it so that the
behavior again matches the documentation.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 3050b6dfc7 (repo-settings.c: simplify the setup,
2021-09-21), the branch for handling fetch.negotiationAlgorithm=default
was deleted. Since this value is documented in
Documentation/config/fetch.txt, restore the check for this value.
Note that this change caused an observable bug: if someone sets
feature.experimental=true in config, and then passes "-c
fetch.negotiationAlgorithm=default" on the command line in an attempt to
override the config, then the override is ignored. Fix the bug by not
ignoring the value of "default".
Technically, before commit 3050b6dfc7, repo-settings would treat any
fetch.negotiationAlgorithm value other than "skipping" or "noop" as a
request for "default", but I think it probably makes more sense to
ignore such broken requests and leave fetch.negotiationAlgorithm with
the default value rather than the value of "default". (If that sounds
confusing, note that "default" is usually the default value, but when
feature.experimental=true, "skipping" is the default value.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix misbehavior in Git.pm that dates back to the very first version of
the library in git.git added in b1edc53d06 (Introduce Git.pm (v4),
2006-06-24). When we fail to execute a command we shouldn't ignore all
signals, those can happen e.g. if abort() is called, or if the command
segfaults.
Because of this we'd consider e.g. a command that died due to LSAN
exiting with abort() successful, as is the case with the tests listed
as running successfully with SANITIZE=leak in 9081a421a6 (checkout:
fix "branch info" memory leaks, 2021-11-16). We did run them
successfully, but only because we ignored these errors.
This was then made worse by the use of "abort_on_error=1" for LSAN
added in 85b81b35ff (test-lib: set LSAN_OPTIONS to abort by default,
2017-09-05). Doing that makes sense, but without providing that option
we'd have a "$? >> 8" of "23" on failure, with abort_on_error=1 we'll
get "0".
All of our tests pass even without the SIGPIPE exception being added
here, but as the code appears to have been trying to ignore it let's
keep ignoring it for now.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When `merge.ff` is set to `only` in .gitconfig, `git subtree pull` will
fail with error `fatal: Not possible to fast-forward, aborting.`, but
the command does want to make merges in these places. Add `--no-ff`
argument to `git merge` to enforce this behaviour.
Signed-off-by: Thomas Koutcher <thomas.koutcher@online.fr>
Reviewed-by: Johannes Altmanninger <aclopte@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When pruning refs fails, we print an error to stderr, but still
exit 0 from 'git fetch'. Since this is a genuine error, fetch
should be exiting with some non-zero exit code. Make it so.
The --prune option was introduced in f360d844de ("builtin-fetch: add
--prune option", 2009-11-10). Unfortunately it's unclear from that
commit whether ignoring the exit code was an oversight or
intentional, but it feels like an oversight.
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a regression in 2.35 that roke the use of "rebase" and "stash"
in a secondary worktree.
* en/keep-cwd:
sequencer, stash: fix running from worktree subdir
The error message when invoking a negotiate-only fetch without providing
any tips incorrectly refers to a --negotiate-tip=* argument. Fix this to
use the actual argument, --negotiation-tip=*.
Signed-off-by: Robert Coup <robert@coup.net.nz>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These were introduced in commit 55dfcf9591 ("sparse-checkout: clear
tracked sparse dirs", 2021-09-08) and missed in my review at the time.
Plug the leaks.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `--diff-filter=<bits>` option allows to filter the diff by certain
criteria, for example `R` to only show renamed files. It also supports
negating a filter via a down-cased letter, i.e. `r` to show _everything
but_ renamed files.
However, the code is a bit overzealous when trying to figure out whether
`git diff` should start with all diff-filters turned on because the user
provided a lower-case letter: if the `--diff-filter` argument starts
with an upper-case letter, we must not start with all bits turned on.
Even worse, it is possible to specify the diff filters in multiple,
separate options, e.g. `--diff-filter=AM [...] --diff-filter=m`.
Let's accumulate the include/exclude filters independently, and only
special-case the "only exclude filters were specified" case after
parsing the options altogether.
Note: The code replaced by this commit took pains to avoid setting any
unused bits of `options->filter`. That was unnecessary, though, as all
accesses happen via the `filter_bit_tst()` function using specific bits,
and setting the unused bits has no effect. Therefore, we can simplify
the code by using `~0` (or in this instance, `~<unwanted-bit>`).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This prepares for a more careful handling of the `--diff-filter`
options over the next few commits.
This commit is best viewed with `--color-moved`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Originally, before we had `--intent-to-add`, there was no way that `git
diff-files` could see added files: if a file did not exist in the index,
`git diff-files` would not show it because it looks only at worktree
files when there is an index entry at the same path.
We used this example in the documentation of the diff options to explain
that not every `--diff-filter=<option>` has an effect in all scenarios.
Even when we added `--intent-to-add`, the comment was still correct,
because initially we showed such files as modified instead of added.
However, when that bug was fixed in feea6946a5 (diff-files: treat
"i-t-a" files as "not-in-index", 2020-06-20), the comment in the
documentation became incorrect.
Let's just remove it.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 8a2cd3f512 (stash: remove the stash.useBuiltin setting, 2020-03-03),
we removed support for `stash.useBuiltin`, but left a warning in its
place.
After almost two years, and several major versions, it is time to remove
even that warning.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 8a2cd3f512 (stash: remove the stash.useBuiltin setting, 2020-03-03),
we removed the setting, and for a couple of major versions, we still
documented the setting, telling users that it is gone.
We can now safely remove even the documentation.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 90a6bb98d1 (legacy stash -p: respect the add.interactive.usebuiltin
setting, 2019-12-21), we added support to use the built-in `add -p` from
the scripted `stash -p`.
In 8a2cd3f512 (stash: remove the stash.useBuiltin setting, 2020-03-03),
we retired the scripted `stash` (including the scripted `stash -p`).
Therefore this support is no longer necessary.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 8a2cd3f512 (stash: remove the stash.useBuiltin setting, 2020-03-03),
we removed `git-legacy-stash.sh`. But `git-sh-setup.sh` somehow still
thinks about it. Let's just not.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Extend the "describe your changes well" section to cover whom we are
trying to help by doing so in the first place.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We give a guidance for proposed log message to write problem
statement first, followed by the reasoning behind, and recipe for,
the solution. Clarify that we describe the situation _before_ the
proposed patch is applied in the present tense (not in the past
tense e.g. "we used to do X, but thanks to this commit we now do Y")
for consistency.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When opening a MIDX/pack-bitmap, we call open_midx_bitmap_1() or
open_pack_bitmap_1() respectively in a loop over the set of MIDXs/packs.
By design, these functions are supposed to be called over every pack and
MIDX, since only one of them should have a valid bitmap.
Ordinarily we return '0' from these two functions in order to indicate
that we successfully loaded a bitmap To signal that we couldn't load a
bitmap corresponding to the MIDX/pack (either because one doesn't exist,
or because there was an error with loading it), we can return '-1'. In
either case, the callers each enumerate all MIDXs/packs to ensure that
at most one bitmap per-kind is present.
But when we fail to load a bitmap that does exist (for example, loading
a MIDX bitmap without finding a corresponding reverse index), we'll
return -1 but leave the 'midx' field non-NULL. So when we fallback to
loading a pack bitmap, we'll complain that the bitmap we're trying to
populate already is "opened", even though it isn't.
Rectify this by setting the '->pack' and '->midx' field back to NULL as
appropriate. Two tests are added: one to ensure that the MIDX-to-pack
bitmap fallback works, and another to ensure we still complain when
there are multiple pack bitmaps in a repository.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a MIDX contains the new `RIDX` chunk, ensure that the reverse index
is read from it instead of the on-disk .rev file. Since we need to
encode the object order in the MIDX itself for correctness reasons,
there is no point in storing the same data again outside of the MIDX.
So, this patch stops writing separate .rev files, and reads it out of
the MIDX itself. This is possible to do with relatively little new code,
since the format of the RIDX chunk is identical to the data in the .rev
file. In other words, we can implement this by pointing the
`revindex_data` field at the reverse index chunk of the MIDX instead of
the .rev file without any other changes.
Note that we have two knobs that are adjusted for the new tests:
GIT_TEST_MIDX_WRITE_REV and GIT_TEST_MIDX_READ_RIDX. The former controls
whether the MIDX .rev is written at all, and the latter controls whether
we read the MIDX's RIDX chunk.
Both are necessary to ensure that the test added at the beginning of
this series continues to work. This is because we always need to write
the RIDX chunk in the MIDX in order to change its checksum, but we want
to make sure reading the existing .rev file still works (since the RIDX
chunk takes precedence by default).
Arguably this isn't a very interesting mode to test, because the
precedence rules mean that we'll always read the RIDX chunk over the
.rev file. But it makes it impossible for a user to induce corruption in
their repository by adjusting the test knobs (since if we had an
either/or knob they could stop writing the RIDX chunk, allowing them to
tweak the MIDX's object order without changing its checksum).
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To prepare for reading the reverse index data out of the MIDX itself,
teach the `test_rev_exists` function to take an expected "source" for
the reverse index data.
When given "rev", it asserts that the MIDX's `.rev` file exists, and is
loaded when verifying the integrity of its bitmaps. Otherwise, it
ensures that trace2 reports the source of the reverse index data as the
same string which was given to test_rev_exists().
The following patch will implement reading the reverse index data from
the MIDX itself.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In t5326, we have a handful of tests that we would like to run twice:
once using the MIDX's new `RIDX` chunk as the source of the
reverse-index cache, and once using the separate `.rev` file.
But because these tests mutate the state of the underlying repository,
and then make assumptions about those mutations occurring in a certain
sequence, simply running the tests twice in the same repository is
awkward.
Instead, extract the core of interesting tests into t/lib-bitmap.sh to
prepare for them to be run twice, each in a separate test script. This
means that they can each operate on a separate repository, removing any
concerns about mutating state.
For now, this patch is a strict cut-and-paste of some tests from t5326.
The tests which did not move are not interesting with respect to the
source of their reverse index data.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To determine which source of data is used for the MIDX's reverse index
cache, introduce a helper which forces loading the reverse index, and
then looks for the special trace2 event introduced in a previous commit.
For now, this helper just looks for when the legacy MIDX .rev file was
loaded, but in a subsequent commit will become parameterized over the
the reverse index's source.
This function replaces checking for the existence of the .rev file. We
could write a similar helper to ensure that the .rev file is cleaned up
after repacking, but it will make subsequent tests more difficult to
write, and provides marginal value since we already check that the MIDX
.bitmap file is removed.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The core.multiPackIndex config became true by default back in 18e449f86b
(midx: enable core.multiPackIndex by default, 2020-09-25), so it is no
longer necessary to enable it explicitly.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a subsequent commit, we'll use the MIDX's new 'RIDX' chunk as a
source for the reverse index's data. But it will be useful for tests to
be able to determine whether the reverse index was loaded from the
separate .rev file, or from a chunk within the MIDX.
To instrument this, add a trace2 event which the tests can look for in
order to determine the reverse index's source.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous patch demonstrates a bug where a MIDX's auxiliary object
order can become out of sync with a MIDX bitmap.
This is because of two confounding factors:
- First, the object order is stored in a file which is named according
to the multi-pack index's checksum, and the MIDX does not store the
object order. This means that the object order can change without
altering the checksum.
- But the .rev file is moved into place with finalize_object_file(),
which link(2)'s the file into place instead of renaming it. For us,
that means that a modified .rev file will not be moved into place if
MIDX's checksum was unchanged.
This fix is to force the MIDX's checksum to change when the preferred
pack changes but the set of packs contained in the MIDX does not. In
other words, when the object order changes, the MIDX's checksum needs to
change with it (regardless of whether the MIDX is tracking the same or
different packs).
This prevents a race whereby changing the object order (but not the
packs themselves) enables a reader to see the new .rev file with the old
MIDX, or similarly seeing the new bitmap with the old object order.
But why can't we just stop hardlinking the .rev into place instead
adding additional data to the MIDX? Suppose that's what we did. Then
when we go to generate the new bitmap, we'll load the old MIDX bitmap,
along with the MIDX that it references. That's fine, since the new MIDX
isn't moved into place until after the new bitmap is generated. But the
new object order *has* been moved into place. So we'll read the old
bitmaps in the new order when generating the new bitmap file, meaning
that without this secondary change, bitmap generation itself would
become a victim of the race described here.
This can all be prevented by forcing the MIDX's checksum to change when
the object order does. By embedding the entire object order into the
MIDX, we do just that. That is, the MIDX's checksum will change in
response to any perturbation of the underlying object order. In t5326,
this will cause the MIDX's checksum to update (even without changing the
set of packs in the MIDX), preventing the stale read problem.
Note that this makes it safe to continue to link(2) the MIDX .rev file
into place, since it is now impossible to have a .rev file that is
out-of-sync with the MIDX whose checksum it references. (But we will do
away with MIDX .rev files later in this series anyway, so this is
somewhat of a moot point).
In theory, it is possible to store a "fingerprint" of the full object
order here, so long as that fingerprint changes at least as often as the
full object order does. Some possibilities here include storing the
identity of the preferred pack, along with the mtimes of the
non-preferred packs in a consistent order. But storing a limited part of
the information makes it difficult to reason about whether or not there
are gaps between the two that would cause us to get bitten by this bug
again.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This patch demonstrates a cause of bitmap corruption that can occur when
the contents of the multi-pack index does not change, but the underlying
object order does.
In this example, we have a MIDX containing two packs, each with a
distinct set of objects (pack A corresponds to the tree, blob, and
commit from the first patch, and pack B corresponds to the second
patch).
First, a MIDX is written where the 'A' pack is preferred. As expected,
the bitmaps generated there are in-tact. But then, we generate an
identical MIDX with a different object order: this time preferring pack
'B'.
Due to a bug which will be explained and fixed in the following commit,
the MIDX is updated, but the .rev file is not, causing the .bitmap file
to be read incorrectly. Specifically, the .bitmap file will contain
correct data, but the auxiliary object order in the .rev file is stale,
causing readers to get confused by reading the new bitmaps using the old
object order.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a regression in 2.35 that roke the use of "rebase" and "stash"
in a secondary worktree.
* en/keep-cwd:
sequencer, stash: fix running from worktree subdir
The tree is not open for new development yet, but let's mark the
beginning of the new cycle before we start merging down regression
fix topics.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add an apostrophe to "signatures" to indicate the possessive
relationship in "the signature's creation".
Signed-off-by: Greg Hurrell <greg@hurrell.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Specifically, replace the tab between "the" and "first" with a space.
Signed-off-by: Greg Hurrell <greg@hurrell.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano
Liginity Lee
Shaoxuan Yuan
Elijah Newren
Ævar Arnfjörð Bjarmason
Thomas Koutcher
Thomas Gummerer
Robert Coup
Johannes Schindelin
Taylor Blau
Greg Hurrell