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git/protocol.c
Jonathan Nieder 3697caf4b9 config: let feature.experimental imply protocol.version=2
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>
2020-05-21 09:31:42 -07:00

98 lines
2.5 KiB
C

#include "cache.h"
#include "config.h"
#include "protocol.h"
static enum protocol_version parse_protocol_version(const char *value)
{
if (!strcmp(value, "0"))
return protocol_v0;
else if (!strcmp(value, "1"))
return protocol_v1;
else if (!strcmp(value, "2"))
return protocol_v2;
else
return protocol_unknown_version;
}
enum protocol_version get_protocol_version_config(void)
{
const char *value;
int val;
const char *git_test_k = "GIT_TEST_PROTOCOL_VERSION";
const char *git_test_v;
if (!git_config_get_string_const("protocol.version", &value)) {
enum protocol_version version = parse_protocol_version(value);
if (version == protocol_unknown_version)
die("unknown value for config 'protocol.version': %s",
value);
return version;
}
if (!git_config_get_bool("feature.experimental", &val) && val)
return protocol_v2;
git_test_v = getenv(git_test_k);
if (git_test_v && *git_test_v) {
enum protocol_version env = parse_protocol_version(git_test_v);
if (env == protocol_unknown_version)
die("unknown value for %s: %s", git_test_k, git_test_v);
return env;
}
return protocol_v0;
}
enum protocol_version determine_protocol_version_server(void)
{
const char *git_protocol = getenv(GIT_PROTOCOL_ENVIRONMENT);
enum protocol_version version = protocol_v0;
/*
* Determine which protocol version the client has requested. Since
* multiple 'version' keys can be sent by the client, indicating that
* the client is okay to speak any of them, select the greatest version
* that the client has requested. This is due to the assumption that
* the most recent protocol version will be the most state-of-the-art.
*/
if (git_protocol) {
struct string_list list = STRING_LIST_INIT_DUP;
const struct string_list_item *item;
string_list_split(&list, git_protocol, ':', -1);
for_each_string_list_item(item, &list) {
const char *value;
enum protocol_version v;
if (skip_prefix(item->string, "version=", &value)) {
v = parse_protocol_version(value);
if (v > version)
version = v;
}
}
string_list_clear(&list, 0);
}
return version;
}
enum protocol_version determine_protocol_version_client(const char *server_response)
{
enum protocol_version version = protocol_v0;
if (skip_prefix(server_response, "version ", &server_response)) {
version = parse_protocol_version(server_response);
if (version == protocol_unknown_version)
die("server is speaking an unknown protocol");
if (version == protocol_v0)
die("protocol error: server explicitly said version 0");
}
return version;
}