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Author SHA1 Message Date
Glen Choo a4e7e317f8 config: add ctx arg to config_fn_t
Add a new "const struct config_context *ctx" arg to config_fn_t to hold
additional information about the config iteration operation.
config_context has a "struct key_value_info kvi" member that holds
metadata about the config source being read (e.g. what kind of config
source it is, the filename, etc). In this series, we're only interested
in .kvi, so we could have just used "struct key_value_info" as an arg,
but config_context makes it possible to add/adjust members in the future
without changing the config_fn_t signature. We could also consider other
ways of organizing the args (e.g. moving the config name and value into
config_context or key_value_info), but in my experiments, the
incremental benefit doesn't justify the added complexity (e.g. a
config_fn_t will sometimes invoke another config_fn_t but with a
different config value).

In subsequent commits, the .kvi member will replace the global "struct
config_reader" in config.c, making config iteration a global-free
operation. It requires much more work for the machinery to provide
meaningful values of .kvi, so for now, merely change the signature and
call sites, pass NULL as a placeholder value, and don't rely on the arg
in any meaningful way.

Most of the changes are performed by
contrib/coccinelle/config_fn_ctx.pending.cocci, which, for every
config_fn_t:

- Modifies the signature to accept "const struct config_context *ctx"
- Passes "ctx" to any inner config_fn_t, if needed
- Adds UNUSED attributes to "ctx", if needed

Most config_fn_t instances are easily identified by seeing if they are
called by the various config functions. Most of the remaining ones are
manually named in the .cocci patch. Manual cleanups are still needed,
but the majority of it is trivial; it's either adjusting config_fn_t
that the .cocci patch didn't catch, or adding forward declarations of
"struct config_context ctx" to make the signatures make sense.

The non-trivial changes are in cases where we are invoking a config_fn_t
outside of config machinery, and we now need to decide what value of
"ctx" to pass. These cases are:

- trace2/tr2_cfg.c:tr2_cfg_set_fl()

  This is indirectly called by git_config_set() so that the trace2
  machinery can notice the new config values and update its settings
  using the tr2 config parsing function, i.e. tr2_cfg_cb().

- builtin/checkout.c:checkout_main()

  This calls git_xmerge_config() as a shorthand for parsing a CLI arg.
  This might be worth refactoring away in the future, since
  git_xmerge_config() can call git_default_config(), which can do much
  more than just parsing.

Handle them by creating a KVI_INIT macro that initializes "struct
key_value_info" to a reasonable default, and use that to construct the
"ctx" arg.

Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-06-28 14:06:39 -07:00
Elijah Newren d1cbe1e6d8 hash-ll.h: split out of hash.h to remove dependency on repository.h
hash.h depends upon and includes repository.h, due to the definition and
use of the_hash_algo (defined as the_repository->hash_algo).  However,
most headers trying to include hash.h are only interested in the layout
of the structs like object_id.  Move the parts of hash.h that do not
depend upon repository.h into a new file hash-ll.h (the "low level"
parts of hash.h), and adjust other files to use this new header where
the convenience inline functions aren't needed.

This allows hash.h and object.h to be fairly small, minimal headers.  It
also exposes a lot of hidden dependencies on both path.h (which was
brought in by repository.h) and repository.h (which was previously
implicitly brought in by object.h), so also adjust other files to be
more explicit about what they depend upon.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-24 12:47:32 -07:00
Elijah Newren 9875058870 treewide: remove cache.h inclusion due to environment.h changes
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-21 10:56:54 -07:00
Elijah Newren 32a8f51061 environment.h: move declarations for environment.c functions from cache.h
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-21 10:56:53 -07:00
Elijah Newren f394e093df treewide: be explicit about dependence on gettext.h
Dozens of files made use of gettext functions, without explicitly
including gettext.h.  This made it more difficult to find which files
could remove a dependence on cache.h.  Make C files explicitly include
gettext.h if they are using it.

However, while compat/fsmonitor/fsm-ipc-darwin.c should also gain an
include of gettext.h, it was left out to avoid conflicting with an
in-flight topic.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-21 10:56:51 -07:00
Junio C Hamano d0732a8120 Merge branch 'jk/unused-post-2.39-part2'
More work towards -Wunused.

* jk/unused-post-2.39-part2: (21 commits)
  help: mark unused parameter in git_unknown_cmd_config()
  run_processes_parallel: mark unused callback parameters
  userformat_want_item(): mark unused parameter
  for_each_commit_graft(): mark unused callback parameter
  rewrite_parents(): mark unused callback parameter
  fetch-pack: mark unused parameter in callback function
  notes: mark unused callback parameters
  prio-queue: mark unused parameters in comparison functions
  for_each_object: mark unused callback parameters
  list-objects: mark unused callback parameters
  mark unused parameters in signal handlers
  run-command: mark error routine parameters as unused
  mark "pointless" data pointers in callbacks
  ref-filter: mark unused callback parameters
  http-backend: mark unused parameters in virtual functions
  http-backend: mark argc/argv unused
  object-name: mark unused parameters in disambiguate callbacks
  serve: mark unused parameters in virtual functions
  serve: use repository pointer to get config
  ls-refs: drop config caching
  ...
2023-03-17 14:03:09 -07:00
Jeff King 4b4e75dd4f serve: use repository pointer to get config
A few of the v2 "serve" callbacks ignore their repository parameter and
read config using the_repository (either directly or implicitly by
calling wrapper functions). This isn't a bug since the server code only
handles a single main repository anyway (and indeed, if you look at the
callers, these repository parameters will always be the_repository). But
in the long run we want to get rid of the_repository, so let's take a
tiny step in that direction.

As a bonus, this silences some -Wunused-parameter warnings.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-02-24 09:13:29 -08:00
Jeff King c4716086d8 ls-refs: drop config caching
The code for the v2 ls-refs command has an ensure_config_read() function
that tries to read the lsrefs.unborn config only once and caches it in
some static global variables.

There's no real need for this caching. In any given process we'd only
need the value twice (once to decide whether to advertise, and once if
somebody runs the command). And since the config code already has its
own cache, each access is only incurring a hash lookup and string
comparison anyway.

Since the values we set are going to be specific to the_repository, the
globals we set are a mild anti-pattern. In practice it's not a bug (yet)
since the server-side v2 code only handles a single repository anyway.
But it doesn't hurt to take a small step in the right direction and
model a good approach.

Note that we currently set two booleans: advertise_unborn and
allow_unborn. But we can get away with a single value, since "advertise"
naturally implies "allow". That lets us just convert this to a function
with a return value.

Note that we still always read from the_repository; we'll deal with that
in a follow-on patch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-02-24 09:13:28 -08:00
Elijah Newren 41771fa435 cache.h: remove dependence on hex.h; make other files include it explicitly
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-02-23 17:25:29 -08:00
Jeff King 91e2ab1587 ls-refs: use repository parameter to iterate refs
The ls_refs() function (for the v2 protocol command of the same name)
takes a repository parameter (like all v2 commands), but ignores it. It
should use it to access the refs.

This isn't a bug in practice, since we only call this function when
serving upload-pack from the main repository. But it's an awkward
gotcha, and it causes -Wunused-parameter to complain.

The main reason we don't use the repository parameter is that the ref
iteration interface we call doesn't have a "refs_" variant that takes a
ref_store. However we can easily add one. In fact, since there is only
one other caller (in ref-filter.c), there is no need to maintain the
non-repository wrapper; that caller can just use the_repository. It's
still a long way from consistently using a repository object, but it's
one small step in the right direction.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-12-13 22:16:22 +09:00
Patrick Steinhardt 9b67eb6fbe refs: get rid of global list of hidden refs
We're about to add a new argument to git-rev-list(1) that allows it to
add all references that are visible when taking `transfer.hideRefs` et
al into account. This will require us to potentially parse multiple sets
of hidden refs, which is not easily possible right now as there is only
a single, global instance of the list of parsed hidden refs.

Refactor `parse_hide_refs_config()` and `ref_is_hidden()` so that both
take the list of hidden references as input and adjust callers to keep a
local list, instead. This allows us to easily use multiple hidden-ref
lists. Furthermore, it allows us to properly free this list before we
exit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-11-17 16:22:51 -05:00
Ævar Arnfjörð Bjarmason 5cf88fd8b0 git-compat-util.h: use "UNUSED", not "UNUSED(var)"
As reported in [1] the "UNUSED(var)" macro introduced in
2174b8c75d (Merge branch 'jk/unused-annotation' into next,
2022-08-24) breaks coccinelle's parsing of our sources in files where
it occurs.

Let's instead partially go with the approach suggested in [2] of
making this not take an argument. As noted in [1] "coccinelle" will
ignore such tokens in argument lists that it doesn't know about, and
it's less of a surprise to syntax highlighters.

This undoes the "help us notice when a parameter marked as unused is
actually use" part of 9b24034754 (git-compat-util: add UNUSED macro,
2022-08-19), a subsequent commit will further tweak the macro to
implement a replacement for that functionality.

1. https://lore.kernel.org/git/220825.86ilmg4mil.gmgdl@evledraar.gmail.com/
2. https://lore.kernel.org/git/220819.868rnk54ju.gmgdl@evledraar.gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-01 10:49:48 -07:00
Jeff King 783a86c142 config: mark unused callback parameters
The callback passed to git_config() must conform to a particular
interface. But most callbacks don't actually look at the extra "void
*data" parameter. Let's mark the unused parameters to make
-Wunused-parameter happy.

Note there's one unusual case here in get_remote_default() where we
actually ignore the "value" parameter. That's because it's only checking
whether the option is found at all, and not parsing its value.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 12:18:55 -07:00
Jean-Noël Avila 1a8aea857e i18n: factorize "invalid value" messages
Use the same message when an invalid value is passed to a command line
option or a configuration variable.

Signed-off-by: Jean-Noël Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-04 13:58:28 -08:00
Junio C Hamano f6c075ad71 Merge branch 'jk/ref-paranoia'
The ref iteration code used to optionally allow dangling refs to be
shown, which has been tightened up.

* jk/ref-paranoia:
  refs: drop "broken" flag from for_each_fullref_in()
  ref-filter: drop broken-ref code entirely
  ref-filter: stop setting FILTER_REFS_INCLUDE_BROKEN
  repack, prune: drop GIT_REF_PARANOIA settings
  refs: turn on GIT_REF_PARANOIA by default
  refs: omit dangling symrefs when using GIT_REF_PARANOIA
  refs: add DO_FOR_EACH_OMIT_DANGLING_SYMREFS flag
  refs-internal.h: reorganize DO_FOR_EACH_* flag documentation
  refs-internal.h: move DO_FOR_EACH_* flags next to each other
  t5312: be more assertive about command failure
  t5312: test non-destructive repack
  t5312: create bogus ref as necessary
  t5312: drop "verbose" helper
  t5600: provide detached HEAD for corruption failures
  t5516: don't use HEAD ref for invalid ref-deletion tests
  t7900: clean up some more broken refs
2021-10-11 10:21:47 -07:00
Junio C Hamano bb1677fc29 Merge branch 'jk/reduce-malloc-in-v2-servers'
Code cleanup to limit memory consumption and tighten protocol
message parsing.

* jk/reduce-malloc-in-v2-servers:
  ls-refs: reject unknown arguments
  serve: reject commands used as capabilities
  serve: reject bogus v2 "command=ls-refs=foo"
  docs/protocol-v2: clarify some ls-refs ref-prefix details
  ls-refs: ignore very long ref-prefix counts
  serve: drop "keys" strvec
  serve: provide "receive" function for session-id capability
  serve: provide "receive" function for object-format capability
  serve: add "receive" method for v2 capabilities table
  serve: return capability "value" from get_capability()
  serve: rename is_command() to parse_command()
2021-09-28 13:06:53 -07:00
Jeff King 67985e4e4a refs: drop "broken" flag from for_each_fullref_in()
No callers pass in anything but "0" here. Likewise to our sibling
functions. Note that some of them ferry along the flag, but none of
their callers pass anything but "0" either.

Nor is anybody likely to change that. Callers which really want to see
all of the raw refs use for_each_rawref(). And anybody interested in
iterating a subset of the refs will likely be happy to use the
now-default behavior of showing broken refs, but omitting dangling
symlinks.

So we can get rid of this whole feature.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27 12:36:45 -07:00
Junio C Hamano 5331af2352 Merge branch 'ab/serve-cleanup'
Code clean-up around "git serve".

* ab/serve-cleanup:
  upload-pack: document and rename --advertise-refs
  serve.[ch]: remove "serve_options", split up --advertise-refs code
  {upload,receive}-pack tests: add --advertise-refs tests
  serve.c: move version line to advertise_capabilities()
  serve: move transfer.advertiseSID check into session_id_advertise()
  serve.[ch]: don't pass "struct strvec *keys" to commands
  serve: use designated initializers
  transport: use designated initializers
  transport: rename "fetch" in transport_vtable to "fetch_refs"
  serve: mark has_capability() as static
2021-09-20 15:20:43 -07:00
Junio C Hamano c2509c5407 Merge branch 'jv/pkt-line-batch'
Reduce number of write(2) system calls while sending the
ref advertisement.

* jv/pkt-line-batch:
  upload-pack: use stdio in send_ref callbacks
  pkt-line: add stdio packet write functions
2021-09-20 15:20:41 -07:00
Jeff King ccf094788c ls-refs: reject unknown arguments
The v2 ls-refs command may receive extra arguments from the client, one
per pkt-line. The spec is pretty clear that the arguments must come from
a specified set, but we silently ignore any unknown entries. For a
well-behaved client this doesn't matter, but it makes testing and
debugging more confusing. Let's tighten this up to match the spec.

In theory this liberal behavior _could_ be useful for extending the
protocol. But:

  - every other part of the protocol requires that the server first
    indicate that it supports the argument; this includes the fetch and
    object-info commands, plus the "unborn" capability added to ls-refs
    itself

  - it's not a very good extension mechanism anyway; without the server
    advertising support, clients would have no idea if the argument was
    silently ignored, or accepted and simply had no effect

So we're not really losing anything by tightening this.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-15 12:25:19 -07:00
Jeff King 7f0e4f6ac2 ls-refs: ignore very long ref-prefix counts
Because each "ref-prefix" capability from the client comes in its own
pkt-line, there's no limit to the number of them that a misbehaving
client may send. We read them all into a strvec, which means the client
can waste arbitrary amounts of our memory by just sending us "ref-prefix
foo" over and over.

One possible solution is to just drop the connection when the limit is
reached. If we set it high enough, then only misbehaving or malicious
clients would hit it. But "high enough" is vague, and it's unfriendly if
we guess wrong and a legitimate client hits this.

But we can do better. Since supporting the ref-prefix capability is
optional anyway, the client has to further cull the response based on
their own patterns. So we can simply ignore the patterns once we cross a
certain threshold. Note that we have to ignore _all_ patterns, not just
the ones past our limit (since otherwise we'd send too little data).

The limit here is fairly arbitrary, and probably much higher than anyone
would need in practice. It might be worth limiting it further, if only
because we check it linearly (so with "m" local refs and "n" patterns,
we do "m * n" string comparisons). But if we care about optimizing this,
an even better solution may be a more advanced data structure anyway.

I didn't bother making the limit configurable, since it's so high and
since Git should behave correctly in either case. It wouldn't be too
hard to do, but it makes both the code and documentation more complex.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-15 12:25:19 -07:00
Junio C Hamano 0057847208 Merge branch 'ab/serve-cleanup' into jk/reduce-malloc-in-v2-servers
* ab/serve-cleanup:
  upload-pack: document and rename --advertise-refs
  serve.[ch]: remove "serve_options", split up --advertise-refs code
  {upload,receive}-pack tests: add --advertise-refs tests
  serve.c: move version line to advertise_capabilities()
  serve: move transfer.advertiseSID check into session_id_advertise()
  serve.[ch]: don't pass "struct strvec *keys" to commands
  serve: use designated initializers
  transport: use designated initializers
  transport: rename "fetch" in transport_vtable to "fetch_refs"
  serve: mark has_capability() as static
2021-09-14 10:56:05 -07:00
Jacob Vosmaer 70afef5cdf upload-pack: use stdio in send_ref callbacks
In both protocol v0 and v2, upload-pack writes one pktline packet per
advertised ref to stdout. That means one or two write(2) syscalls per
ref. This is problematic if these writes become network sends with
high overhead.

This commit changes both send_ref callbacks to use buffered IO using
stdio.

To give an example of the impact: I set up a single-threaded loop that
calls ls-remote (with HTTP and protocol v2) on a local GitLab
instance, on a repository with 11K refs. When I switch from Git
v2.32.0 to this patch, I see a 40% reduction in CPU time for Git, and
65% for Gitaly (GitLab's Git RPC service).

So using buffered IO not only saves syscalls in upload-pack, it also
saves time in things that consume upload-pack's output.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-01 10:20:39 -07:00
Patrick Steinhardt f54b9f21ca ls-refs: reuse buffer when sending refs
In the initial reference advertisement, the Git server will first
announce all of its references to the client. The logic is handled in
`send_ref()`, which will allocate a new buffer for each refline it is
about to send. This is quite wasteful: instead of allocating a new
buffer each time, we can just reuse a buffer.

Improve this by passing in a buffer via the `ls_refs_data` struct which
is then reused on each reference.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25 15:55:29 -07:00
Ævar Arnfjörð Bjarmason 28a592e4f4 serve.[ch]: don't pass "struct strvec *keys" to commands
The serve.c API added in ed10cb952d (serve: introduce git-serve,
2018-03-15) was passing in the raw capabilities "keys", but nothing
downstream of it ever used them.

Let's remove that code because it's not needed. If we do end up
needing to pass information about the advertisement in the future
it'll make more sense to have serve.c parse the capabilities keys and
pass the result of its parsing, rather than expecting expecting its
API users to parse the same keys again.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-05 08:59:37 -07:00
Junio C Hamano 69571dfe21 Merge branch 'jt/clone-unborn-head'
"git clone" tries to locally check out the branch pointed at by
HEAD of the remote repository after it is done, but the protocol
did not convey the information necessary to do so when copying an
empty repository.  The protocol v2 learned how to do so.

* jt/clone-unborn-head:
  clone: respect remote unborn HEAD
  connect, transport: encapsulate arg in struct
  ls-refs: report unborn targets of symrefs
2021-02-17 17:21:40 -08:00
Junio C Hamano 6254fa1359 Merge branch 'tb/ls-refs-optim'
The ls-refs protocol operation has been optimized to narrow the
sub-hierarchy of refs/ it walks to produce response.

* tb/ls-refs-optim:
  ls-refs.c: traverse prefixes of disjoint "ref-prefix" sets
  ls-refs.c: initialize 'prefixes' before using it
  refs: expose 'for_each_fullref_in_prefixes'
2021-02-05 16:40:45 -08:00
Jonathan Tan 59e1205d16 ls-refs: report unborn targets of symrefs
When cloning, we choose the default branch based on the remote HEAD.
But if there is no remote HEAD reported (which could happen if the
target of the remote HEAD is unborn), we'll fall back to using our local
init.defaultBranch. Traditionally this hasn't been a big deal, because
most repos used "master" as the default. But these days it is likely to
cause confusion if the server and client implementations choose
different values (e.g., if the remote started with "main", we may choose
"master" locally, create commits there, and then the user is surprised
when they push to "master" and not "main").

To solve this, the remote needs to communicate the target of the HEAD
symref, even if it is unborn, and "git clone" needs to use this
information.

Currently, symrefs that have unborn targets (such as in this case) are
not communicated by the protocol. Teach Git to advertise and support the
"unborn" feature in "ls-refs" (by default, this is advertised, but
server administrators may turn this off through the lsrefs.unborn
config). This feature indicates that "ls-refs" supports the "unborn"
argument; when it is specified, "ls-refs" will send the HEAD symref with
the name of its unborn target.

This change is only for protocol v2. A similar change for protocol v0
would require independent protocol design (there being no analogous
position to signal support for "unborn") and client-side plumbing of the
data required, so the scope of this patch set is limited to protocol v2.

The client side will be updated to use this in a subsequent commit.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05 13:49:53 -08:00
Taylor Blau b3970c702c ls-refs.c: traverse prefixes of disjoint "ref-prefix" sets
ls-refs performs a single revision walk over the whole ref namespace,
and sends ones that match with one of the given ref prefixes down to the
user.

This can be expensive if there are many refs overall, but the portion of
them covered by the given prefixes is small by comparison.

To attempt to reduce the difference between the number of refs
traversed, and the number of refs sent, only traverse references which
are in the longest common prefix of the given prefixes. This is very
reminiscent of the approach taken in b31e2680c4 (ref-filter.c: find
disjoint pattern prefixes, 2019-06-26) which does an analogous thing for
multi-patterned 'git for-each-ref' invocations.

The callback 'send_ref' is resilient to ignore extra patterns by
discarding any arguments which do not begin with at least one of the
specified prefixes.

Similarly, the code introduced in b31e2680c4 is resilient to stop early
at metacharacters, but we only pass strict prefixes here. At worst we
would return too many results, but the double checking done by send_ref
will throw away anything that doesn't start with something in the prefix
list.

Finally, if no prefixes were provided, then implicitly add the empty
string (which will match all references) since this matches the existing
behavior (see the "no restrictions" comment in "ls-refs.c:ref_match()").

Original-patch-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-22 18:57:27 -08:00
Jacob Vosmaer 83befd3724 ls-refs.c: initialize 'prefixes' before using it
Correctly initialize the "prefixes" strvec using strvec_init() instead
of simply zeroing it via the earlier memset().

There's no way to trigger a crash, since the first 'ref-prefix' command
will initialize the strvec via the 'ALLOC_GROW' in 'strvec_push_nodup()'
(the alloc and nr variables are already zero'd, so the call to
ALLOC_GROW is valid).

If no "ref-prefix" command was given, then the call to
'ls-refs.c:ref_match()' will abort early after it reads the zero in
'prefixes->nr'. Likewise, strvec_clear() will only call free() on the
array, which is NULL, so we're safe there, too.

But, all of this is dangerous and requires more reasoning than it would
if we simply called 'strvec_init()', so do that.

Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-22 18:57:27 -08:00
Jeff King 36a317929b refs: switch peel_ref() to peel_iterated_oid()
The peel_ref() interface is confusing and error-prone:

  - it's typically used by ref iteration callbacks that have both a
    refname and oid. But since they pass only the refname, we may load
    the ref value from the filesystem again. This is inefficient, but
    also means we are open to a race if somebody simultaneously updates
    the ref. E.g., this:

      int some_ref_cb(const char *refname, const struct object_id *oid, ...)
      {
              if (!peel_ref(refname, &peeled))
                      printf("%s peels to %s",
                             oid_to_hex(oid), oid_to_hex(&peeled);
      }

    could print nonsense. It is correct to say "refname peels to..."
    (you may see the "before" value or the "after" value, either of
    which is consistent), but mentioning both oids may be mixing
    before/after values.

    Worse, whether this is possible depends on whether the optimization
    to read from the current iterator value kicks in. So it is actually
    not possible with:

      for_each_ref(some_ref_cb);

    but it _is_ possible with:

      head_ref(some_ref_cb);

    which does not use the iterator mechanism (though in practice, HEAD
    should never peel to anything, so this may not be triggerable).

  - it must take a fully-qualified refname for the read_ref_full() code
    path to work. Yet we routinely pass it partial refnames from
    callbacks to for_each_tag_ref(), etc. This happens to work when
    iterating because there we do not call read_ref_full() at all, and
    only use the passed refname to check if it is the same as the
    iterator. But the requirements for the function parameters are quite
    unclear.

Instead of taking a refname, let's instead take an oid. That fixes both
problems. It's a little funny for a "ref" function not to involve refs
at all. The key thing is that it's optimizing under the hood based on
having access to the ref iterator. So let's change the name to make it
clear why you'd want this function versus just peel_object().

There are two other directions I considered but rejected:

  - we could pass the peel information into the each_ref_fn callback.
    However, we don't know if the caller actually wants it or not. For
    packed-refs, providing it is essentially free. But for loose refs,
    we actually have to peel the object, which would be wasteful in most
    cases. We could likewise pass in a flag to the callback indicating
    whether the peeled information is known, but that complicates those
    callbacks, as they then have to decide whether to manually peel
    themselves. Plus it requires changing the interface of every
    callback, whether they care about peeling or not, and there are many
    of them.

  - we could make a function to return the peeled value of the current
    iterated ref (computing it if necessary), and BUG() otherwise. I.e.:

      int peel_current_iterated_ref(struct object_id *out);

    Each of the current callers is an each_ref_fn callback, so they'd
    mostly be happy. But:

      - we use those callbacks with functions like head_ref(), which do
        not use the iteration code. So we'd need to handle the fallback
        case there, anyway.

      - it's possible that a caller would want to call into generic code
        that sometimes is used during iteration and sometimes not. This
        encapsulates the logic to do the fast thing when possible, and
        fallback when necessary.

The implementation is mostly obvious, but I want to call out a few
things in the patch:

  - the test-tool coverage for peel_ref() is now meaningless, as it all
    collapses to a single peel_object() call (arguably they were pretty
    uninteresting before; the tricky part of that function is the
    fast-path we see during iteration, but these calls didn't trigger
    that). I've just dropped it entirely, though note that some other
    tests relied on the tags we created; I've moved that creation to the
    tests where it matters.

  - we no longer need to take a ref_store parameter, since we'd never
    look up a ref now. We do still rely on a global "current iterator"
    variable which _could_ be kept per-ref-store. But in practice this
    is only useful if there are multiple recursive iterations, at which
    point the more appropriate solution is probably a stack of
    iterators. No caller used the actual ref-store parameter anyway
    (they all call the wrapper that passes the_repository).

  - the original only kicked in the optimization when the "refname"
    pointer matched (i.e., not string comparison). We do likewise with
    the "oid" parameter here, but fall back to doing an actual oideq()
    call. This in theory lets us kick in the optimization more often,
    though in practice no current caller cares. It should never be
    wrong, though (peeling is a property of an object, so two refs
    pointing to the same object would peel identically).

  - the original took care not to touch the peeled out-parameter unless
    we found something to put in it. But no caller cares about this, and
    anyway, it is enforced by peel_object() itself (and even in the
    optimized iterator case, that's where we eventually end up). We can
    shorten the code and avoid an extra copy by just passing the
    out-parameter through the stack.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-21 15:51:31 -08:00
Jeff King d70a9eb611 strvec: rename struct fields
The "argc" and "argv" names made sense when the struct was argv_array,
but now they're just confusing. Let's rename them to "nr" (which we use
for counts elsewhere) and "v" (which is rather terse, but reads well
when combined with typical variable names like "args.v").

Note that we have to update all of the callers immediately. Playing
tricks with the preprocessor is hard here, because we wouldn't want to
rewrite unrelated tokens.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30 19:18:06 -07:00
Jeff King ef8d7ac42a strvec: convert more callers away from argv_array name
We eventually want to drop the argv_array name and just use strvec
consistently. There's no particular reason we have to do it all at once,
or care about interactions between converted and unconverted bits.
Because of our preprocessor compat layer, the names are interchangeable
to the compiler (so even a definition and declaration using different
names is OK).

This patch converts remaining files from the first half of the alphabet,
to keep the diff to a manageable size.

The conversion was done purely mechanically with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe '
    s/ARGV_ARRAY/STRVEC/g;
    s/argv_array/strvec/g;
  '

and then selectively staging files with "git add '[abcdefghjkl]*'".
We'll deal with any indentation/style fallouts separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Jeff King dbbcd44fb4 strvec: rename files from argv-array to strvec
This requires updating #include lines across the code-base, but that's
all fairly mechanical, and was done with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe 's/argv-array.h/strvec.h/'

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:17 -07:00
Jeff King 4845b77245 upload-pack: handle unexpected delim packets
When processing the arguments list for a v2 ls-refs or fetch command, we
loop like this:

  while (packet_reader_read(request) != PACKET_READ_FLUSH) {
          const char *arg = request->line;
	  ...handle arg...
  }

to read and handle packets until we see a flush. The hidden assumption
here is that anything except PACKET_READ_FLUSH will give us valid packet
data to read. But that's not true; PACKET_READ_DELIM or PACKET_READ_EOF
will leave packet->line as NULL, and we'll segfault trying to look at
it.

Instead, we should follow the more careful model demonstrated on the
client side (e.g., in process_capabilities_v2): keep looping as long
as we get normal packets, and then make sure that we broke out of the
loop due to a real flush. That fixes the segfault and correctly
diagnoses any unexpected input from the client.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27 12:18:48 -07:00
Jeff King 533e088250 upload-pack: strip namespace from symref data
Since 7171d8c15f (upload-pack: send symbolic ref information as
capability, 2013-09-17), we've sent cloning and fetching clients special
information about which branch HEAD is pointing to, so that they don't
have to guess based on matching up commit ids.

However, this feature has never worked properly with the GIT_NAMESPACE
feature.  Because upload-pack uses head_ref_namespaced(find_symref), we
do find and report on refs/namespaces/foo/HEAD instead of the actual
HEAD of the repo. This makes sense, since the branch pointed to by the
top-level HEAD may not be advertised at all. But we do two things wrong:

  1. We report the full name refs/namespaces/foo/HEAD, instead of just
     HEAD. Meaning no client is going to bother doing anything with that
     symref, since we're not otherwise advertising it.

  2. We report the symref destination using its full name (e.g.,
     refs/namespaces/foo/refs/heads/master). That's similarly useless to
     the client, who only saw "refs/heads/master" in the advertisement.

We should be stripping the namespace prefix off of both places (which
this patch fixes).

Likely nobody noticed because we tend to do the right thing anyway. Bug
(1) means that we said nothing about HEAD (just refs/namespace/foo/HEAD).
And so the client half of the code, from a45b5f0552 (connect: annotate
refs with their symref information in get_remote_head(), 2013-09-17),
does not annotate HEAD, and we use the fallback in guess_remote_head(),
matching refs by object id. Which is usually right. It only falls down
in ambiguous cases, like the one laid out in the included test.

This also means that we don't have to worry about breaking anybody who
was putting pre-stripped names into their namespace symrefs when we fix
bug (2). Because of bug (1), nobody would have been using the symref we
advertised in the first place (not to mention that those symrefs would
have appeared broken for any non-namespaced access).

Note that we have separate fixes here for the v0 and v2 protocols. The
symref advertisement moved in v2 to be a part of the ls-refs command.
This actually gets part (1) right, since the symref annotation
piggy-backs on the existing ref advertisement, which is properly
stripped. But it still needs a fix for part (2). The included tests
cover both protocols.

Reported-by: Bryan Turner <bturner@atlassian.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-28 10:02:00 -07:00
Junio C Hamano 9c96ab9872 Merge branch 'jt/namespaced-ls-refs-fix'
Fix namespace support in protocol v2.

* jt/namespaced-ls-refs-fix:
  ls-refs: filter refs using namespace-stripped name
2019-02-05 14:26:15 -08:00
Jonathan Tan e2f41a0a5a ls-refs: filter refs using namespace-stripped name
If a user fetches refs/heads/master from a repo with namespace "ns", the
remote is expected to (1) not send the real refs/heads/master, and (2)
send refs/namespaces/ns/refs/heads/master with the name
refs/heads/master. (1) indeed happens now, but not (2) - Git only sends
refs that have the user-given prefix, but it checks them against the
full name of the ref (the one starting with refs/namespaces), and not
the namespace-stripped one.

This is demonstrated by the patch in the test. Currently, it results in
"fatal: couldn't find remote ref refs/heads/master" despite both
unnamespaced and namespaced master being present. With the code change,
it produces the expected result.

Check the ref prefixes against the namespace-stripped name.

This bug was discovered through applying patches [1] that override
protocol.version to 2 in repositories when running tests, allowing us to
notice differences in behavior across different protocol versions.

[1] https://public-inbox.org/git/cover.1547677183.git.jonathantanmy@google.com/

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-18 12:48:41 -08:00
Jeff King e20b4192a3 upload-pack: support hidden refs with protocol v2
In the v2 protocol, upload-pack's advertisement has been moved to the
"ls-refs" command. That command does not respect hidden-ref config (like
transfer.hiderefs) at all, and advertises everything.

While there are some features that are not supported in v2 (e.g., v2
always allows fetching any sha1 without respect to advertisements), the
lack of this feature is not documented and is likely just a bug. Let's
make it work, as otherwise upgrading a server to a v2-capable git will
start exposing these refs that the repository admin has asked to remain
hidden.

Note that we assume we're operating on behalf of a fetch here, since
that's the only thing implemented in v2 at this point. See the in-code
comment. We'll have to figure out how this works when the v2 push
protocol is designed (both here in ls-refs, but also rejecting updates
to hidden refs).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-10 11:15:37 -08:00
Brandon Williams 72d0ea0056 ls-refs: introduce ls-refs server command
Introduce the ls-refs server command.  In protocol v2, the ls-refs
command is used to request the ref advertisement from the server.  Since
it is a command which can be requested (as opposed to mandatory in v1),
a client can sent a number of parameters in its request to limit the ref
advertisement based on provided ref-prefixes.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-15 12:01:08 -07:00