remote: introduce remote.<name>.serverOption configuration

Currently, server options for Git protocol v2 can only be specified via
the command line option "--server-option" or "-o", which is inconvenient
when users want to specify a list of default options to send. Therefore,
we are introducing a new configuration to hold a list of default server
options, akin to the `push.pushOption` configuration for push options.

Initially, I named the new configuration `fetch.serverOption` to align
with `push.pushOption`. However, after discussing with Patrick, it was
renamed to `remote.<name>.serverOption` as suggested, because:

1. Server options are designed to be server-specific, making it more
   logical to use a per-remote configuration.
2. Using "fetch." prefixed configurations in git-clone or git-ls-remote
   seems out of place and inconsistent in design.

The parsing logic for `remote.<name>.serverOption` also relies on
`transport.c:parse_transport_option`, similar to `push.pushOption`, and
they follow the same priority design:

1. Server options set in lower-priority configuration files (e.g.,
   /etc/gitconfig or $HOME/.gitconfig) can be overridden or unset in
   more specific repository configurations using an empty string.
2. Command-line specified server options take precedence over those from
   the configuration.

Server options from configuration are stored to the corresponding
`remote.h:remote` as a new field `server_options`.  The field will be
utilized in the subsequent commit to help initialize the
`server_options` of `transport.h:transport`.

And documentation have been updated accordingly.

Helped-by: Patrick Steinhardt <ps@pks.im>
Helped-by: Junio C Hamano <gitster@pobox.com>
Reported-by: Liu Zhongbo <liuzhongbo.6666@bytedance.com>
Signed-off-by: Xing Xin <xingxin.xx@bytedance.com>
Reviewed-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/remote.c b/remote.c
index e291e8ff5c..1777d45086 100644
--- a/remote.c
+++ b/remote.c
@@ -24,6 +24,7 @@
 #include "advice.h"
 #include "connect.h"
 #include "parse-options.h"
+#include "transport.h"
 
 enum map_direction { FROM_SRC, FROM_DST };
 
@@ -143,6 +144,7 @@ static struct remote *make_remote(struct remote_state *remote_state,
 	ret->name = xstrndup(name, len);
 	refspec_init(&ret->push, REFSPEC_PUSH);
 	refspec_init(&ret->fetch, REFSPEC_FETCH);
+	string_list_init_dup(&ret->server_options);
 
 	ALLOC_GROW(remote_state->remotes, remote_state->remotes_nr + 1,
 		   remote_state->remotes_alloc);
@@ -166,6 +168,7 @@ static void remote_clear(struct remote *remote)
 	free((char *)remote->uploadpack);
 	FREE_AND_NULL(remote->http_proxy);
 	FREE_AND_NULL(remote->http_proxy_authmethod);
+	string_list_clear(&remote->server_options, 0);
 }
 
 static void add_merge(struct branch *branch, const char *name)
@@ -508,6 +511,9 @@ static int handle_config(const char *key, const char *value,
 	} else if (!strcmp(subkey, "vcs")) {
 		FREE_AND_NULL(remote->foreign_vcs);
 		return git_config_string(&remote->foreign_vcs, key, value);
+	} else if (!strcmp(subkey, "serveroption")) {
+		return parse_transport_option(key, value,
+					      &remote->server_options);
 	}
 	return 0;
 }