It is useful for performance monitoring and debugging purposes to know
the wire protocol used for remote operations. This may differ from the
version set in local configuration due to differences in version and/or
configuration between the server and the client. Therefore, log the
negotiated wire protocol version via trace2, for both clients and
servers.
Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Protocol v2 became the default in v2.26.0 via 684ceae32d (fetch: default
to protocol version 2, 2019-12-23). More widespread use turned up a
regression in negotiation. That was fixed in v2.27.0 via 4fa3f00abb
(fetch-pack: in protocol v2, in_vain only after ACK, 2020-04-27), but we
also reverted the default to v0 as a precuation in 11c7f2a30b (Revert
"fetch: default to protocol version 2", 2020-04-22).
In v2.28.0, we re-enabled it for experimental users with 3697caf4b9
(config: let feature.experimental imply protocol.version=2, 2020-05-20)
and haven't heard any complaints. v2.28 has only been out for 2 months,
but I'd generally expect people turning on feature.experimental to also
stay pretty up-to-date. So we're not likely to collect much more data by
waiting. In addition, we have no further reports from people running
v2.26.0, and of course some people have been setting protocol.version
manually for ages.
Let's move forward with v2 as the default again. It's possible there are
still lurking bugs, but we won't know until it gets more widespread use.
And we can find and squash them just like any other bug at this point.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are two functions to get a single config string:
- git_config_get_string()
- git_config_get_string_const()
One might naively think that the first one allocates a new string and
the second one just points us to the internal configset storage. But
in fact they both allocate a new copy; the second one exists only to
avoid having to cast when using it with a const global which we never
intend to free.
The documentation for the function explains that clearly, but it seems
I'm not alone in being surprised by this. Of 17 calls to the function,
13 of them leak the resulting value.
We could obviously fix these by adding the appropriate free(). But it
would be simpler still if we actually had a non-allocating way to get
the string. There's git_config_get_value() but that doesn't quite do
what we want. If the config key is present but is a boolean with no
value (e.g., "[foo]bar" in the file), then we'll get NULL (whereas the
string versions will print an error and die).
So let's introduce a new variant, git_config_get_string_tmp(), that
behaves as these callers expect. We need a new name because we have new
semantics but the same function signature (so even if we converted the
four remaining callers, topics in flight might be surprised). The "tmp"
is because this value should only be held onto for a short time. In
practice it's rare for us to clear and refresh the configset,
invalidating the pointer, but hopefully the "tmp" makes callers think
about the lifetime. In each of the converted cases here the value only
needs to last within the local function or its immediate caller.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git 2.26 used protocol v2 as its default protocol, but soon after
release, users noticed that the protocol v2 negotiation code was prone
to fail when fetching from some remotes that are far ahead of others
(such as linux-next.git versus Linus's linux.git). That has been
fixed by 0b07eecf6e (Merge branch 'jt/v2-fetch-nego-fix',
2020-05-01), but to be cautious, we are using protocol v0 as the
default in 2.27 to buy some time for any other unanticipated issues to
surface.
To that end, let's ensure that users requesting the bleeding edge
using the feature.experimental flag *do* get protocol v2. This way,
we can gain experience with a wider audience for the new protocol
version and be more confident when it is time to enable it by default
for all users in some future Git version.
Implementation note: this isn't with the rest of the
feature.experimental options in repo-settings.c because those are tied
to a repository object, whereas this code path is used for operations
like "git ls-remote" that do not require a repository.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 684ceae32d.
Users fetching from linux-next and other kernel remotes are reporting
that the limited ref advertisement causes negotiation to reach
MAX_IN_VAIN, resulting in too-large fetches.
Reported-by: Lubomir Rintel <lkundrak@v3.sk>
Reported-by: "Dixit, Ashutosh" <ashutosh.dixit@intel.com>
Reported-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The Git users at $DAYJOB have been using protocol v2 as a default for
~1.5 years now and others have been also reporting good experiences
with it, so it seems like a good time to bump the default version. It
produces a significant performance improvement when fetching from
repositories with many refs, such as
https://chromium.googlesource.com/chromium/src.
This only affects the client, not the server. (The server already
defaults to supporting protocol v2.) The protocol change is backward
compatible, so this should produce no significant effect when
contacting servers that only speak protocol v0.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The GIT_TEST_PROTOCOL_VERSION environment variable can be used to
upgrade the version of Git protocol used in tests. If both
GIT_TEST_PROTOCOL_VERSION and 'protocol.version' are set, the higher
value wins.
For usage within tests, these semantics are too complex. Instead,
always use the value from protocol.version configuration when it is
set, falling back to GIT_TEST_PROTOCOL_VERSION. This way, the envvar
provides a reliable preview of what will happen if the default
protocol version is changed.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Define a GIT_TEST_PROTOCOL_VERSION environment variable meant to be used
from tests. When set, this ensures protocol.version is at least the
given value, allowing the entire test suite to be run as if this
configuration is in place for all repositories.
As of this patch, all tests pass whether GIT_TEST_PROTOCOL_VERSION is
unset or set to 0. Some tests fail when GIT_TEST_PROTOCOL_VERSION is set
to 1 or 2, but this will be dealt with in subsequent patches.
This is based on work by Ævar Arnfjörð Bjarmason.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce protocol_v2, a new value for 'enum protocol_version'.
Subsequent patches will fill in the implementation of protocol_v2.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create protocol.{c,h} and provide functions which future servers and
clients can use to determine which protocol to use or is being used.
Also introduce the 'GIT_PROTOCOL' environment variable which will be
used to communicate a colon separated list of keys with optional values
to a server. Unknown keys and values must be tolerated. This mechanism
is used to communicate which version of the wire protocol a client would
like to use with a server.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
