Now that it is safe to call git_hash_discard() even after finalizing it,
we can simplify our cleanup logic a bit. This is mostly undoing a few
bits of 64337aecde (csum-file: always finalize or discard hash,
2026-07-02):
- We no longer need a separate free_hashfile_memory() function for
finalize_hashfile(). It can just call free_hashfile(), which will
now discard (or not) the hash as appropriate.
- When f->skip_hash is set, we don't need to discard; we can rely on
free_hashfile() to do it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
You must always either finalize or discard a hash context to release any
resources, but you must call only one such function. This creates extra
work for some callers, since their cleanup code paths need to know
whether they got there via their happy path (and the finalization
happened) or due to an error (in which case they need to discard).
Let's add an "active" flag that turns a redundant discard into a noop.
That lets you safely do this:
git_hash_init(&ctx, algo);
...
if (some_error)
goto out;
...
git_hash_final(result, &ctx);
out:
git_hash_discard(&ctx);
This should avoid future errors, and will also let us simplify a few
existing callers (in future patches).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We want people to use the git_hash_*() wrappers rather than the bare
function pointers in the git_hash_algo struct. Let's document them
rather than the bare pointers, and warn people away from the pointers.
Coccinelle will eventually force the use of the wrappers, but it's
helpful to lead readers in the right direction from the start.
While we're here we can document a few other bits of wisdom I've turned
up while working in this area:
- You have to initialize the destination of a git_hash_clone(). This
is something we may eventually change for efficiency, but we should
definitely document the requirement for now.
- You must eventually finalize or discard a hash, since some backends
may allocate resources during initialization.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous patch added a coccinelle rule to make sure callers always
use git_hash_init() rather than direct function pointers from the algo
struct.
Let's do the same for the rest of the git_hash_*() wrappers. I split
these out because they're a bit different: they implicitly use the algop
pointer in the git_hash_ctx. So when we convert:
-algo->update_fn(&ctx, buf, len);
+git_hash_update(&ctx, buf, len);
we drop the reference to algo entirely! But this is always going to be
the right thing. If "algo" does not match what is in ctx.algop, then
we'd already be invoking undefined behavior.
So in addition to making it possible to add more logic to the
git_hash_*() functions, we're avoiding the need to pass around the extra
algo pointer and make sure that it matches what's in "ctx".
The rest of the patch is the mechanical application of that coccinelle
patch, plus a minor cleanup in test-synthesize.c to drop a now-unused
function parameter (since we don't have to pass around the algo
separately anymore).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We'd like to add more logic to git_hash_init(), but many callers skip it
and call algop->init_fn() directly. Let's make sure we're consistently
using the wrapper by adding a coccinelle rule.
Besides the coccinelle file itself, this is a purely mechanical
conversion based on the patch it generates. There should be no bare
init_fn() calls left (except for the one in the wrapper).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our git_hash_discard() is a bit hacky: it just calls git_hash_final()
into a dummy result buffer, using the side effect that each
implementation's Final() function will also free any resources.
This is probably not too terrible, since generating the final hash is
not that expensive and we'd mostly call discard on unusual or error code
paths. But we can do better by widening the platform API a bit to add an
explicit discard function.
This requires an annoying amount of boilerplate:
- Each algorithm needs a git_$ALGO_discard() wrapper that dereferences
the union'd git_hash_ctx into the type-safe field. So sha1 + sha256
+ sha1-unsafe, plus a BUG() for the unknown algo. And then these all
need to be referenced in the git_hash_algo structs.
- Platforms which don't do anything special to discard now need a
fallback function which does nothing. And we need this for each algo
(sha1, sha256, and sha1-unsafe).
- Platforms which do need to discard must define their discard
functions. This includes sha1/openssl, sha256/openssl, and
sha256/gcrypt (no sha1-unsafe here as it sits atop the sha1/openssl
functions).
- Algo selection needs to point platform_*_Discard to the appropriate
underlying macro, or indicate that the fallback should be used. We
have a similar situation for the Clone function (where a straight
memcpy() of the context struct is not enough for some platforms).
I've tied Discard to the same flag used by Clone here, since they
are basically the same problem: is the hash context a sequence of
bytes, or does it need smart copying/discarding?
It's easy to miss a case here since we don't even compile the
implementations we aren't using. I've tested with each of:
- no flags, which uses our internal sha1/sha256 implementations, both
of which exercise the noop fallback function
- OPENSSL_SHA1_UNSAFE=1, which checks that our unsafe macro
redirections work
- OPENSSL_SHA1=1, though you should not do that in real life!
- OPENSSL_SHA256=1, passes tests with GIT_TEST_DEFAULT_HASH=sha256
- GCRYPT_SHA256=1, which likewise passes
The other implementations do not set the CLONE_HELPER flag, so they
treat the context as bytes and should be fine with the fallback.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our abstracted hash-algorithm API allows for cloning a hash context. By
default this just memcpy()s the bytes, but specific implementations can
provide a custom clone function.
Our API is based around the way that OpenSSL works, which is that you
first initialize the destination context, then copy into it. In our code
that is this:
algo->init_fn(&dst);
git_hash_clone(&dst, src);
and that translates into OpenSSL calls like:
/* init_fn */
dst->ectx = EVP_MD_CTX_new();
EVP_DigestInit_ex(dst->ectx, EVP_sha256());
/* clone */
EVP_MD_CTX_copy_ex(dst->ectx, src->ectx);
So the allocation happens in the first step, and then the clone is just
copying values (the DigestInit is initializing values that just get
overwritten, but that's not wrong, just a little inefficient).
But libgcrypt doesn't work like that! Its copy function initializes dst
from scratch. So when using the sha256 gcrypt backend, that becomes:
/* init_fn; this allocates */
gcry_md_open(&dst, GCRY_MD_SHA256);
/* clone; this also allocates, leaking the previous value! */
gcry_md_copy(&dst, src);
You can see the leaks in the test suite by running:
make \
SANITIZE=leak \
GCRYPT_SHA256=1 \
GIT_TEST_DEFAULT_SHA=256 \
test
which has many failures, as opposed to building with OPENSSL_SHA256,
which is leak-free.
The easy fix here is for the clone function to close the open context
we're about to overwrite. It's a little inefficient (we did a pointless
open in the init function), but probably not a big deal in practice.
If our API went the other way, assuming that we're always cloning into
garbage bytes, then we could be more efficient. We'd teach OpenSSL's
clone function to do its own new(), skip the DigestInit, and then copy
into it. And gcrypt could stick with just the copy() call.
But look again at the asymmetry in the very first code example. We call
the init function straight from the git_hash_algo struct, and then
subsequent calls are dispatched through our git_hash_* wrappers. If you
wanted to clone into an uninitialized destination, you'd do something
like:
algo->clone_fn(&dst, src);
instead. That would require changing all of the callers. There's not
that many of them, but I don't know that it's worth changing our calling
conventions to try to reclaim this tiny bit of efficiency.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Usually an object request results in finish_http_object_request()
calling git_hash_final_oid(), after we've received all of the data. But
if we hit an error, we'll bail early and free the http_object_request,
dropping the git_hash_ctx entirely. This can cause a leak for hash
implementations that allocate memory in their context, like OpenSSL >=
3.0.
The obvious fix is for abort_http_object_request() to call
git_hash_discard(), under the assumption that every request is either
finished or aborted. But that's not quite true:
1. Not everybody calls the abort function. Sometimes they jump
straight to release_http_object_request(). So we'd have to put it
there.
2. After the finish function finalizes the hash, we can still
encounter errors! In that case we end up aborting or releasing,
and they must not discard that hash (since that would be a
double-free).
So we'll keep a flag marking the validity of the hash_ctx field of the
request. The lifetime is simple: it is valid immediately after creation,
up until we call finalize. And then our release function can just
conditionally discard the hash based on that flag.
This fixes test failures in t5550 and t5619 when run with:
make SANITIZE=leak \
OPENSSL_SHA256=1 \
GIT_TEST_DEFAULT_HASH=sha256 \
test
The flag handling could be removed if the hash-discard function were
idempotent. This could be done easily-ish by having the underlying
hash functions (like the ones in sha256/openssl.h) set the context
pointer to NULL after free-ing. But it's something that every platform
implementation would have to remember to do, and the benefit for the
callers is not that huge (it would let us shave a few lines here and
probably in a few other spots).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The happy path of check_stream_oid() is to initialize a hash, feed the
loose object zlib stream into it, and then get the final result. But if
we hit a zlib error or see extra cruft we'll bail early with an error.
Since we never call git_hash_final() in this cases, any resources held
by the git_hash_ctx may be leaked. Our default hash algorithms don't
allocate anything in the hash_ctx, but some implementations do. For
example, running:
make SANITIZE=leak \
OPENSSL_SHA256=1 \
GIT_TEST_DEFAULT_HASH=sha256 \
test
will fail t1450, since it feeds corrupted objects that cause us to bail
from check_stream_oid(). This patch fixes it by discarding the hash in
those early return paths. Trying to jump to a common "out:" label is not
worth it here, as we must _not_ discard a hash that was already fed to
git_hash_final(). And the hash_ctx itself does not carry any information
(so we cannot check for a NULL pointer, etc).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When computing a patch-id, we have a flush_one_hunk() helper that calls
git_hash_final() on our running hunk git_hash_ctx, and then
reinitializes that context for the next hunk.
When we run out of hunks to look at, we return, discarding the
git_hash_ctx. This can cause a leak if the hash implementation we are
using allocates any memory during its initialization. This includes
OpenSSL >= 3.0, for both SHA-1 and SHA-256. Normally we would not use
SHA-1 here at all, as we only recommend using non-DC implementations for
the "unsafe" variant (and patch-id, though they probably _could_ use the
unsafe variant, were never taught to do so).
But it is certainly a problem for SHA-256, which you can see with:
make SANITIZE=leak \
OPENSSL_SHA256=1 \
GIT_TEST_DEFAULT_HASH=sha256 \
test
That results in leak failures of 60 scripts, 57 of which are fixed by
this patch (basically anything which runs rebase will hit this case).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A hashfile_checkpoint struct is basically just a copy of the hash_ctx
state at a given point in the file. As such, it contains its own
git_hash_ctx which may (depending on the underlying hash implementation)
need to be discarded when we're done with it.
Let's add a "release" function which cleans up the hash context it
holds. I chose "release" here and not "discard" because you'd use this
to clean up every checkpoint, whether you used it or not. As opposed to
git_hash_discard(), which is needed only if you didn't call
git_hash_final().
There are only two callers which use hashfile_checkpoints, and we can
add release calls to both. When built with "SANITIZE=leak
OPENSSL_SHA1_UNSAFE=1", this makes both t1050 and t9300 leak-free.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a hashfile struct is created, we always initialize the git_hash_ctx
inside it. We usually end up in hashfile_finalize(), which passes that
ctx to git_hash_final(), cleaning it up.
But a few code paths don't do so:
1. If we bail on the hashfile and call free_hashfile() directly rather
than finalizing.
2. If the skip_hash flag is set, the hashfile_finalize() call will
never call git_hash_final(). (You might think that we should just
avoid git_hash_init() entirely in this case, but the skip_hash flag
is set by the caller after the hashfile is initialized).
For most hash implementations this is OK, but for ones that allocate on
initialization it causes a memory leak. You can see many failures by
running:
make SANITIZE=leak OPENSSL_SHA1_UNSAFE=1 test
since OpenSSL >= 3.0 is such an allocating hash implementation (and
csum-file uses the "unsafe" algorithm variant).
We can solve this by calling git_hash_discard() as appropriate.
Note that free_hashfile() is used both directly by callers to abort
without finalizing, and by hashfile_finalize() to free memory. In the
latter case we _don't_ want to call git_hash_discard(), because we'll
already have either finalized or discarded it. So we'll push that to an
internal "free_memory" function, and keep free_hashfile() as the public
interface to abort a hashfile without finalizing.
This fix makes several scripts leak-free with the command above: t1600,
t1601, t2107, t7008, t9210, t9211.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The usual life-cycle for a git_hash_ctx is calling git_hash_init(),
adding some data, and then using git_hash_final() to get the output
digest and free any resources.
Sometimes we decide to abort the operation without the final() call
(e.g., due to errors or other reasons). In that case we just abandon the
hash_ctx completely and let it go out of scope. For most hash
implementations this is fine; they were just holding values directly in
the struct.
But some implementations do allocate memory, and in these cases we leak
the memory. Notably OpenSSL >= 3.0 requires us to allocate the digest
context on the heap with EVP_MD_CTX_new().
Let's provide a git_hash_discard() function that can be used in these
code paths to free any resources. For now we'll implement it by just
calling git_hash_final() into a dummy output, relying on its side effect
of freeing the resources. Our view of the underlying hash implementation
is abstracted behind the platform_SHA_* macros, so that's the best we
can do without widening that interface.
It's a little inefficient, but probably not noticeably so in practice,
especially as we'd usually hit this on an error code path. And by
abstracting it in this function, we can later swap it out when the
platform_SHA interface lets us do so.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit c3d034df16 (csum-file: introduce discard_hashfile(), 2024-07-25)
added a cleanup function that no longer has any callers. In that commit
we adjusted do_write_index() to use the new function. But a similar fix
occurred on a parallel branch, making free_hashfile() public, and the
merge resolution in 1b6b2bfae5 (Merge branch 'ps/leakfixes-part-4',
2024-08-23) took the free_hashfile() version.
So now we have two functions, discard_hashfile() and free_hashfile(),
and we only need one. Which one do we want to keep?
The only difference between them is that the discard variant also closes
the descriptors held in the struct. Let's look at the three callers:
1. In finalize_hashfile() we've either already closed the descriptors
(if the CSUM_CLOSE flag is passed) or the caller didn't want them
closed (if it didn't pass that flag). So we want the more limited
free_hashfile().
2. In object-file.c:flush_packfile_transaction() we close the
descriptor ourselves. So discard_hashfile() could save us a line of
code.
3. In do_write_index() we don't close the descriptor. This was the spot
for which c3d034df16 added the discard function in the first place,
but I'm skeptical that closing the descriptor here is the right
thing. It is true that we are done with the descriptor at this
point and closing it would be ideal. But we don't really own it!
The descriptor comes from a tempfile struct (as part of a lock) and
that tempfile will hold on to the descriptor and try to close it
when it is deleted. This might happen at the end of the program, in
which case the double-close is mostly harmless (we might
accidentally close some other open descriptor, but at that point
we're just closing and unlinking everything we can).
But in theory it could also cause subtle bugs. If do_write_index()
fails, we return the error up the stack and would eventually end up
in write_locked_index(). There we roll back the lock file on error,
which will close the descriptor. So now we get our double close,
and we might actually close something else that was opened in the
interim.
This is probably unlikely in practice (as soon as we see the error
we'd mostly be unwinding the stack, not opening new files). But it
highlights a potential problem with the discard_hashfile()
interface: the hashfile doesn't necessarily own that descriptor.
Note that I said "descriptors" plural above. Those callers all care
about the "fd" member of the struct. But discard_hashfile() also closes
check_fd. That is only used if the struct is initialized with
hashfd_check(), and neither of its two callers call either discard or
free (they always "finalize" instead). So closing it is irrelevant for
the current callers.
I think we're better off sticking with the simpler free_hashfile()
interface, and the handful of callers can decide how to handle the
descriptors themselves.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The Apache timeout in HTTP tests has been increased to prevent test
failures on heavily loaded CI runners. The tests creating an
enormous number of refs have been isolated to their own repositories
to avoid slowing down subsequent tests.
* jk/t5551-expensive-test-timeouts-fix:
t5551: put many-tags case into its own repo
t/lib-httpd: bump apache timeout
Most of the t5551 http fetch tests use a handful of refs. But there are
a few test cases which check our handling of large numbers of refs.
These tests use the same server-side repo, so all subsequent tests end
up having to consider those extra refs, too.
The result is that the test script is a bit slower than it needs to be.
In a normal run, moving the "2,000 tags" test into its own repo drops my
runtime for the whole script from ~2.7s to ~1.9s.
This is a modest gain, but when we add the "--long" flag it gets much
bigger. There we trigger a test (marked with EXPENSIVE) that adds
100,000 tags, and the script runtime jumps to ~95s. But if we use the
same "many tags" repo for that, our runtime drops to just ~37s.
This is a pretty easy win to drop the cost of the script. It may even be
a larger gain on a heavily loaded system, since one of the main costs
here is unpacked refs, which are heavy on system time and I/O costs.
It's possible we are reducing test coverage, since all of those other
tests were inadvertently using large ref advertisements (and thus could
have uncovered some unexpected interaction). But that seems somewhat
unlikely; the tests targeted at the large number of refs are doing
roughly similar things to the other tests.
Note that the real performance culprit is the 100k-tag --long test, not
the 2k-tag one. So we could just let the 100k one use its own repo, and
keep the 2k tags in the main repo. But since these two tests are
somewhat interlinked, it's easier to just move them both (and it does
provide a small gain even for the 2000-tag test). I also notice that the
2000-tag test is gated on the CMDLINE_LIMIT prereq, and without that the
later EXPENSIVE test will fail (since we won't have a too-many-refs
clone). Nobody seems to have noticed or complained after many years, and
I left it alone for this patch.
Signed-off-by: Jeff King <peff@peff.net>
[jc: made the new "many-tags.git" bare to match the original "repo.git"]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We lost ability to use https:// proxies during this cycle; this is
a hotfix for the regression.
* js/http-https-proxy-fix:
http: accept https:// proxies again
Since enabling more tests with 7a094d68a2 (ci: run expensive tests on
push builds to integration branches, 2026-05-08), we sometimes see test
failures or timeouts in GitHub CI. The culprit seems to be the "enormous
ref negotiation" test in t5551, which creates ~100k tag refs in our http
server-side repo.
Iterating through the loose refs of this repo to generate a ref
advertisement can take a long time, especially on a platform with slow
I/O. On my otherwise unloaded local machine, a cold cache ref
advertisement takes ~10s. On a busy CI machine running tests in
parallel, it can presumably top 60s, which runs afoul of Apache's
default CGI timeout.
The result in t5551 is a test failure, where Apache simply hangs up the
connection and the client reports an error. But worse, t5559 runs the
same test with HTTP/2, and a bug in Apache causes the connection to hang
indefinitely! We eventually see this as a CI timeout after 6 hours.
Let's bump Apache's timeout to something much larger: 600 seconds. This
doesn't eliminate the possibility of a timeout, but it makes it much
less likely. It should eliminate both the test failures and the CI
timeouts in practice, and it protects us from running into similar
problems with other tests in the future.
There are two counter-arguments to consider.
One, could/should we just make the test faster? Probably yes. The
biggest mistake here is having such an absurd number of unpacked refs on
a system which is bottle-necked on I/O. But I think it's worth bumping
the timeout so that we can fix this (and possibly other) correctness
issues, and then consider performance separately (which we'll do in
subsequent patches).
And two, is this just papering over a problem that users might see in
the real world? We could teach Git to handle this case more gracefully
with optimizations or keep-alives. But I think it's really an artificial
situation. You need a combination of this silly number of loose refs,
plus a very heavily loaded system. If you were trying to run a real
server and it took more than 60s to generate the ref advertisement, I
don't think the timeout is your biggest problem. Your crappy service is,
and you should adjust your resources to match your load. I.e., it is
probably reasonable for Git to assume that advertisements happen
fast-ish and don't need protocol-level keepalives.
Though the patch here is small, tons of work went into analyzing the
problem. Many thanks to the contributors credited below.
Helped-by: Michael Montalbo <mmontalbo@gmail.com>
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 663d7abe07 (http: reject unsupported proxy URL schemes,
2026-05-05), set_curl_proxy_type() returns 0 only for the "http"
and SOCKS variants via dedicated early returns, and -1 for
everything else. The "https" branch configures the CURL handle for
HTTPS proxying but then falls through to the trailing `return -1`
intended for unknown schemes, so the caller in get_curl_handle()
treats a perfectly valid https:// proxy URL as unsupported and
refuses to use it.
Noticed while looking into a Coverity report against the same
function; the unchecked curl_easy_setopt() return values it flags
are orthogonal to this fix.
Assisted-by: Opus 4.7
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a "Preserving Quotation Marks" section to prevent AI-assisted
translation and review from incorrectly converting language-specific
UTF-8 curly quotes (e.g., „ U+201E, " U+201C for Bulgarian) into
ASCII straight quotes " (U+0022), which would cause PO string
truncation and syntax errors.
Also update the "Special characters" item in the Quality checklist
to reference the new section.
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
In t4216 we have have a prerequisite that is active in case the system's
`char` type is signed by default. This prerequisite isn't really used by
anything though: while it is used to guard one of our tests, that
specific test is essentially a no-op. So all this infrastructure does is
to provide some debugging hint to a reader that pays a lot of attention.
Besides that, the way we set up the prerequisite also results in broken
TAP output on systems where `char` is unsigned by default: we use
`test_cmp()` to diff two files outside of of any test body, and if the
files differ we enable the prerequisite. If so, the call to `test_cmp()`
would also print output, and that output is of course not valid TAP
output.
That wasn't a problem before 389c83025d (t: let prove fail when parsing
invalid TAP output, 2026-06-04), because our TAP parser was configured
to be lenient. But starting with that commit, t4216 is now failing on
systems with unsigned chars.
Drop the whole infrastructure. The prerequisite is not used anywhere
else, and the only location where it's used doesn't really provide much
value.
Reported-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Tested-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Xcode 15 and later has a linker set to complain when the same library
archive is listed twice on the command line. Squelch the annoyance.
* hn/macos-linker-warning:
config.mak.uname: avoid macOS dup-library warning
Jeff King