Compiling with -O2 can interact badly with LSan's leak-checker, causing
false positives. Imagine a simplified example like:
char *str = allocate_some_string();
if (some_func(str) < 0)
die("bad str");
free(str);
The compiler may eliminate "str" as a stack variable, and just leave it
in a register. The register is preserved through most of the function,
including across the call to some_func(), since we'd eventually need to
free it. But because die() is marked with NORETURN, the compiler knows
that it doesn't need to save registers, and just clobbers it.
When die() eventually exits, the leak-checker runs. It looks in
registers and on the stack for any reference to the memory allocated by
str (which would indicate that it's not leaked), but can't find one. So
it reports it as a leak.
Neither system is wrong, really. The C standard (mostly section 5.1.2.3)
defines an abstract machine, and compilers are allowed to modify the
program as long as the observable behavior of that abstract machine is
unchanged. Looking at random memory values on the stack is undefined
behavior, and not something that the optimizer needs to support. But
there really isn't any other way for a leak checker to work; it
inherently has to do undefined things like scouring memory for pointers.
So the two things are inherently at odds with each other. We can't fix
it by changing the code, because from the perspective of the program
running in an abstract machine, there is no leak.
This has caused real false positives in the past, like:
- https://lore.kernel.org/git/patch-v3-5.6-9a44204c4c9-20211022T175227Z-avarab@gmail.com/
- https://lore.kernel.org/git/Yy4eo6500C0ijhk+@coredump.intra.peff.net/
- https://lore.kernel.org/git/Y07yeEQu+C7AH7oN@nand.local/
This patch makes those go away by forcing -O0 when compiling with LSan.
There are a few ways we could do this:
- we could just teach the linux-leaks CI job to set -O0. That's the
smallest change, and means we wouldn't get spurious CI failures. But
it doesn't help people looking for leaks manually or in a specific
test (and because the problem depends on the vagaries of the
optimizer, investigating these can waste a lot of time in
head-scratching as the problem comes and goes)
- we default to -O2 in CFLAGS; we could pull this out to a separate
variable ("-O$(O)" or something) and modify "O" when LSan is in use.
This is the most flexible, in that you could still build with "make
O=2 SANITIZE=leak" if you really wanted to (say, for experimenting).
But it would also fail to kick in if the user defines their own
CFLAGS variable, which again leads to head-scratching.
- we can just stick -O0 into BASIC_CFLAGS when enabling LSan. Since
this comes after the user-provided CFLAGS, it will override any
previous -O setting found there. This is more foolproof, albeit less
flexible. If you want to experiment with an optimized leak-checking
build, you'll have to put "-O2 -fsanitize=leak" into CFLAGS
manually, rather than using our SANITIZE=leak Makefile magic.
Since the final one is the least likely to break in normal use, this
patch uses that approach.
The resulting build is a little slower, of course, but since LSan is
already about 2x slower than a regular build, another 10% slowdown isn't
that big a deal.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When attempting to initialize a repository object in an unsafe
directory, a syntax error is reported (Can't use string as a HASH ref
while strict refs in use). Fix this runtime error by adding the required
semicolon after the catch statement.
Without the semicolon, the result of the following line (i.e., the
result of Cwd::abs_path) is passed as the third argument to Error.pm's
catch function. That function expects that its third argument,
$clauses, is a hash reference, and trying to access a string as a hash
reference is a fatal error.
[1] https://lore.kernel.org/git/20221011182607.f1113fff-9333-427d-ba45-741a78fa6040@korelogic.com/
Reported-by: Hank Leininger <hlein@korelogic.com>
Signed-off-by: Michael McClimon <michael@mcclimon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`git repack` supports a `--pack-kept-objects` flag which more or less
translates to whether or not we pass `--honor-pack-keep` down to `git
pack-objects` when assembling a new pack.
This behavior has existed since ee34a2bead (repack: add
`repack.packKeptObjects` config var, 2014-03-03). In that commit, the
documentation was extended to say:
[...] Note that we still do not delete `.keep` packs after
`pack-objects` finishes.
Unfortunately, this is not the case when `--pack-kept-objects` is
combined with a `--geometric` repack. When doing a geometric repack, we
include `.keep` packs when enumerating available packs only when
`pack_kept_objects` is set.
So this all works fine when `--no-pack-kept-objects` (or similar) is
given. Kept packs are excluded from the geometric roll-up, so when we go
to delete redundant packs (with `-d`), no `.keep` packs appear "below
the split" in our geometric progression.
But when `--pack-kept-objects` is given, things can go awry. Namely,
when a kept pack is included in the list of packs tracked by the
`pack_geometry` struct *and* part of the pack roll-up, we will delete
the `.keep` pack when we shouldn't.
Note that this *doesn't* result in object corruption, since the `.keep`
pack's objects are still present in the new pack. But the `.keep` pack
itself is removed, which violates our promise from back in ee34a2bead.
But there's more. Because `repack` computes the geometric roll-up
independently from selecting which packs belong in a MIDX (with
`--write-midx`), this can lead to odd behavior. Consider when a `.keep`
pack appears below the geometric split (ie., its objects will be part of
the new pack we generate).
We'll write a MIDX containing the new pack along with the existing
`.keep` pack. But because the `.keep` pack appears below the geometric
split line, we'll (incorrectly) try to remove it. While this doesn't
corrupt the repository, it does cause us to remove the MIDX we just
wrote, since removing that pack would invalidate the new MIDX.
Funny enough, this behavior became far less noticeable after e4d0c11c04
(repack: respect kept objects with '--write-midx -b', 2021-12-20), which
made `pack_kept_objects` be enabled by default only when we were writing
a non-MIDX bitmap.
But e4d0c11c04 didn't resolve this bug, it just made it harder to notice
unless callers explicitly passed `--pack-kept-objects`.
The solution is to avoid trying to remove `.keep` packs during
`--geometric` repacks, even when they appear below the geometric split
line, which is the approach this patch implements.
Co-authored-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we write a MIDX bitmap after repacking, it is possible that the
repository would be left in a state with both pack- and multi-pack
reachability bitmaps.
This can occur, for instance, if a pack that was kept (either by having
a .keep file, or during a geometric repack in which it is not rolled up)
has a bitmap file, and the repack wrote a multi-pack index and bitmap.
When loading a reachability bitmap for the repository, the multi-pack
one is always preferred, so the pack-based one is redundant. Let's
remove it unconditionally, even if '-d' isn't passed, since there is no
practical reason to keep both around. The patch below does just that.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We have a generic ll_merge_fn, but not every implementation needs every
parameter. In particular, neither binary nor ext merges care about names
(since they do not generate conflict markers), and most do not need to
look at the ll_merge_driver itself.
Ironically, neither ll_xdl_merge() nor ll_union_merge() needs to have
their driver parameter annotated (even though both are named
drv_unused!). This is because they may fall back to calling
ll_binary_merge() directly. And even though that function won't look at
it, we still pass it along, and hence it is "used" in the caller.
We could get away with passing NULL, but that's likely more confusing
and brittle than just passing along our own driver. And we have to keep
the driver parameter in all callbacks, since ll_ext_merge() uses it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We have a virtual pickaxe_fn for handling -G versus -S pickaxe options.
They need to take the same set of parameters, but of course they care
about different ones (e.g., a regex -G will never use a kwset).
Mark the unused ones to appease -Wunused-parameter.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The null stream filter unsurprisingly does not look at its "filter"
argument, since it just eats bytes. But we can't drop it, since it has
to conform to the same virtual interface that real filters do. Mark the
unused parameter to appease -Wunused-parameter.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We squelch error/warning output by passing a noop handler to
set_error_routine(). We need to tell the compiler that this is intended
so that it doesn't trigger -Wunused-parameter.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In parse_git_diff_header(), we have a table-driven parser that maps
strings to handler functions. Not all handlers need all of the
parameters; let's mark the unused ones to appease -Wunused-parameter.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When parsing approxidates, we use a table to map special strings (like
"noon") to functions which handle them. Not all functions need the "now"
parameter, as they are not relative (e.g., "yesterday" does, but "pm"
does not). Let's annotate those to make -Wunused-parameter happy.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
String-lists may be used with callbacks for clearing or iteration. These
callbacks need to conform to a particular interface, even though not
every callback needs all of its parameters. Mark the unused ones to make
-Wunused-parameter happy.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 0'th entry of our hash_algos array fills out the virtual methods
with a series of functions which simply BUG(). This is the right thing
to do, since the point is to catch use of an invalid algo parameter, but
we need to annotate them to appease -Wunused-parameters.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a platform feature isn't available or in use, we sometimes
conditionally compile empty or trivial functions to turn these into
noops. We need to annotate their parameters so that -Wunused-parameters
won't complain about them.
Note that there are many more of these in compat/mingw.h, but we'll
leave them for now, as there's some trickery required to get the UNUSED
macro available there.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The parse-options callback for --again soaks up all remaining options by
manipulating the parse_opt_ctx's argc and argv fields. Even though it
has to look at both, the actual parsing happens via the do_reupdate()
helper, which only looks at the argv half (by passing it along to
parse_pathspec). So that helper doesn't need to see argc at all.
Note that the helper does look at "argv + 1" without confirming that
argc is greater than 0. We know this is correct because it is skipping
past the actual "--again" string, which will always be present. However,
to make what's going on more obvious, let's move that "+1" into the
caller, which has the matching "-1" when fixing up the ctx's argc/argv.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The module_list_compute() function takes an argc/argv pair, but never
looks at argc. This is OK, as the NULL terminator in argv is sufficient
for our purposes (we feed it to parse_pathspec(), which takes only the
array, not a count).
Note that one of the callers _looks_ like it would be buggy, but isn't:
we pass 0/NULL for argc/argv from module_foreach(), so finding the
terminating NULL in that argv naively would segfault. However,
parse_pathspec() is smart enough to interpret a bare NULL as an empty
argv.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The callback interface for xdiff_emit_line_fn gives us a line/len pair,
but diffstat_consume() never looks at "len". At first glance this seems
like a bug that could cause us to read further than xdiff intends. But
in practice, we read only the first character, and xdiff would never
pass us an empty line.
Let's add a run-time assertion that this is true, which clarifies our
assumption and silences -Wunused-parameter.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git branch --edit-description" on an unborh branch misleadingly
said that no such branch exists, which has been corrected.
* rj/branch-edit-desc-unborn:
branch: description for non-existent branch errors
Remove error detection from a function that fetches from promisor
remotes, and make it die when such a fetch fails to bring all the
requested objects, to give an early failure to various operations.
* jt/promisor-remote-fetch-tweak:
promisor-remote: die upon failing fetch
promisor-remote: remove a return value
Clarify that "the sentence after <area>: prefix does not begin with
a capital letter" rule applies only to the commit title.
* jc/use-of-uc-in-log-messages:
SubmittingPatches: use usual capitalization in the log message body
Update comment in the Makefile about the RUNTIME_PREFIX config knob.
* dd/document-runtime-prefix-better:
Makefile: clarify runtime relative gitexecdir
The code to clean temporary object directories (used for
quarantine) tried to remove them inside its signal handler, which
was a no-no.
* jc/tmp-objdir:
tmp-objdir: skip clean up when handling a signal
"GIT_EDITOR=: git branch --edit-description" resulted in failure,
which has been corrected.
* jc/branch-description-unset:
branch: do not fail a no-op --edit-desc
Code clean-up.
* jk/cleanup-callback-parameters:
attr: drop DEBUG_ATTR code
commit: avoid writing to global in option callback
multi-pack-index: avoid writing to global in option callback
test-submodule: inline resolve_relative_url() function
By default, use of fsmonitor on a repository on networked
filesystem is disabled. Add knobs to make it workable on macOS.
* ed/fsmonitor-on-networked-macos:
fsmonitor: fix leak of warning message
fsmonitor: add documentation for allowRemote and socketDir options
fsmonitor: check for compatability before communicating with fsmonitor
fsmonitor: deal with synthetic firmlinks on macOS
fsmonitor: avoid socket location check if using hook
fsmonitor: relocate socket file if .git directory is remote
fsmonitor: refactor filesystem checks to common interface
Treating the action as a string is a hang over from the scripted
rebase. The last commit removed the only remaining use of the action
that required a string so lets convert the other action users to use
the existing action enum instead. If we ever need the action name as a
string in the future the action_names array exists exactly for that
purpose.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When aborting a rebase the reflog message looks like
rebase (abort): updating HEAD
which is not very informative. Improve the message by mentioning the
branch that we are returning to as we do at the end of a successful
rebase so it looks like.
rebase (abort): returning to refs/heads/topic
If GIT_REFLOG_ACTION is set in the environment we no longer omit
"(abort)" from the reflog message. We don't omit "(start)" and
"(finish)" when starting and finishing a rebase in that case so we
shouldn't omit "(abort)".
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The apply backend creates slightly different reflog messages to the
merge backend when starting or finishing a rebase and when picking
commits. These differences make it harder than it needs to be to parse
the reflog (I have a script that reads the finishing messages from
rebase and it is a pain to have to accommodate two different message
formats). While it is possible to determine the backend used for a
rebase from the reflog messages, the differences are not designed for
that purpose. c2417d3af7 (rebase: drop '-i' from the reflog for
interactive-based rebases, 2020-02-15) removed the clear distinction
between the reflog messages of the two backends without complaint.
As the merge backend is the default it is likely to be the format most
common in existing reflogs. For that reason the apply backend is changed
to format its reflog messages to match the merge backend as closely as
possible. Note that there is still a difference as when committing a
conflict resolution the apply backend will use "(pick)" rather than
"(continue)" because it is not currently possible to change the message
for a single commit.
In addition to c2417d3af7 we also changed the reflog messages in
68aa495b59 (rebase: implement --merge via the interactive machinery,
2018-12-11) and 2ac0d6273f (rebase: change the default backend from "am"
to "merge", 2020-02-15). This commit makes the same change to "git
rebase --apply" that 2ac0d6273f made to "git rebase" without any backend
specific options. As the messages are changed to use an existing format
any scripts that can parse the reflog messages of the default rebase
backend should be unaffected by this change.
There are existing tests for the messages from both backends which are
adjusted to ensure that they do not get out of sync in the future.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The reflog messages when finishing a rebase hard code "rebase" rather
than using GIT_REFLOG_ACTION.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The reflog message for every pick after running "rebase --skip" looks
like
rebase (skip) (pick): commit subject line
Fix this by not appending " (skip)" to the reflog action.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The reflog message for a conflict resolution committed by "rebase
--continue" looks like
rebase (continue): commit subject line
Unfortunately the reflog message each subsequent pick look like
rebase (continue) (pick): commit subject line
Fix this by setting the reflog message for "rebase --continue" in
sequencer_continue() so it does not affect subsequent commits. This
introduces a memory leak similar to the one leaking GIT_REFLOG_ACTION
in pick_commits(). Both of these will be fixed in a future series that
stops the sequencer calling setenv().
If we fail to commit the staged changes then we error out so
GIT_REFLOG_ACTION does not need to be reset in that case.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor the tests in preparation for adding more tests in the next
few commits. The reworked tests use the same function for testing both
the "merge" and "apply" backends. The test coverage for the "apply"
backend now includes setting GIT_REFLOG_ACTION.
Note that rebasing the "conflicts" branch does not create any
conflicts yet. A commit to do that will be added in the next commit
and the diff ends up smaller if we have don't rename the branch when
it is added.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use move_to_original_branch() when reattaching HEAD after a fast-forward
rather than open coding a copy of that code. move_to_original_branch()
does not call reset_head() if head_name is NULL but there should be no
user visible changes even though we currently call reset_head() in that
case. The reason for this is that the reset_head() call does not add a
message to the reflog because we're not changing the commit that HEAD
points to and so lock_ref_for_update() elides the update. When head_name
is not NULL then reset_head() behaves like "git symbolic-ref" and so the
reflog is updated.
Note that the removal of "strbuf_release(&msg)" is safe as there is an
identical call just above this hunk which can be seen by viewing the
diff with -U6.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* pw/rebase-keep-base-fixes:
rebase --keep-base: imply --no-fork-point
rebase --keep-base: imply --reapply-cherry-picks
rebase: factor out branch_base calculation
rebase: rename merge_base to branch_base
rebase: store orig_head as a commit
rebase: be stricter when reading state files containing oids
t3416: set $EDITOR in subshell
t3416: tighten two tests
Given the name of the option it is confusing if --keep-base actually
changes the base of the branch without --fork-point being explicitly
given on the command line.
The combination of --keep-base with an explicit --fork-point is still
supported even though --fork-point means we do not keep the same base
if the upstream branch has been rewound. We do this in case anyone is
relying on this behavior which is tested in t3431[1]
[1] https://lore.kernel.org/git/20200715032014.GA10818@generichostname/
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As --keep-base does not rebase the branch it is confusing if it
removes commits that have been cherry-picked to the upstream branch.
As --reapply-cherry-picks is not supported by the "apply" backend this
commit ensures that cherry-picks are reapplied by forcing the upstream
commit to match the onto commit unless --no-reapply-cherry-picks is
given.
Reported-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Separate out calculating the merge base between 'onto' and 'HEAD' from
the check for whether we can fast-forward or not. This means we can skip
the fast-forward checks when the rebase is forced and avoid calculating
the merge-base between 'HEAD' and 'onto' when --keep-base is given.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge_base is not a very descriptive name, the variable always holds
the merge-base of 'branch' and 'onto' which is commit at the base of
the branch being rebased so rename it to branch_base.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using a struct commit rather than a struct oid to hold orig_head means
that we error out straight away if the branch being rebased does not
point to a commit. It also simplifies the code that handles finding
the merge base and fork point as it no longer has to convert from an
oid to a commit.
To avoid changing the behavior of "git rebase <upstream> <branch>" we
keep the existing call to read_ref() and use lookup_commit_object()
on the oid returned by that rather than calling
lookup_commit_reference_by_name() which applies the ref dwim rules to
its argument.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The state files for 'onto' and 'orig_head' should contain a full hex
oid, change the reading functions from get_oid() to get_oid_hex() to
reflect this. They should also name commits and not tags so add and use
a function that looks up a commit from an oid like
lookup_commit_reference() but without dereferencing tags.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As $EDITOR is exported, setting it in one test affects all subsequent
tests. Avoid this by always setting it in a subshell. Also remove a
couple of unnecessary call to set_fake_editor where the editor does
not change the todo list.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a check for the correct error message to the tests that check we
require a single merge base so we can be sure the rebase failed for
the correct reason. Also rename the tests to reflect what they are
testing.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Tests in this script use an unusual and hard to reason about
conditional construct
if expression; then false; else :; fi
Change them to use more idiomatic construct:
! expression
Cc: Christian Couder <christian.couder@gmail.com>
Cc: Hariom Verma <hariom18599@gmail.com>
Signed-off-by: Nsengiyumva Wilberforce <nsengiyumvawilberforce@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When debugging bitmap generation performance, it is useful to know how
many bitmaps were generated from scratch, and how many were the result
of permuting the bit-order of an existing bitmap.
Keep track of the latter, and emit the count as a trace2_data line to
aid in debugging.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When debugging MIDX and MIDX-bitmap related issues, it is useful to
figure out where Git is spending its time.
GitHub has been using the below trace2 regions to instrument various
components of generating a MIDX itself, as well time spent preparing to
build a MIDX bitmap.
These are limited to instrumenting the following functions:
- midx.c::find_commits_for_midx_bitmap()
- midx.c::midx_pack_order()
- midx.c::prepare_midx_packing_data()
- midx.c::write_midx_bitmap()
- midx.c::write_midx_internal()
- midx.c::write_midx_reverse_index()
to start and end with a trace2_region_enter() and trace2_region_leave(),
respectively.
The category for all of these is "midx", which matches the existing
convention. The region description matches the name of the function.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
