Update receive-pack to use an atomic transaction IFF the client negotiated
that it wanted atomic-push.
This leaves the default behaviour to be the old non-atomic one ref at a
time update. This is to cause as little disruption as possible to existing
clients. It is unknown if there are client scripts that depend on the old
non-atomic behaviour so we make it opt-in for now.
Later patch in this series also adds a configuration variable where you can
override the atomic push behaviour on the receiving repo and force it
to use atomic updates always.
If it turns out over time that there are no client scripts that depend on the
old behaviour we can change git to default to use atomic pushes by default
and instead offer an opt-out argument for people that do not want atomic
updates at all.
Signed-off-by: Ronnie Sahlberg <sahlberg@xxxxxxxxxx>
---
builtin/receive-pack.c | 55 ++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 44 insertions(+), 11 deletions(-)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index f6b20cb..47f778d 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -47,6 +47,8 @@ static void *head_name_to_free;
static int sent_capabilities;
static int shallow_update;
static const char *alt_shallow_file;
+struct strbuf err = STRBUF_INIT;
+struct ref_transaction *transaction;
static enum deny_action parse_deny_action(const char *var, const char *value)
{
@@ -577,26 +579,38 @@ static char *update(struct command *cmd, struct shallow_info *si)
return NULL; /* good */
}
else {
- struct strbuf err = STRBUF_INIT;
- struct ref_transaction *transaction;
-
if (shallow_update && si->shallow_ref[cmd->index] &&
update_shallow_ref(cmd, si))
return xstrdup("shallow error");
-
- transaction = transaction_begin(&err);
- if (!transaction ||
- transaction_update_sha1(transaction, namespaced_name,
+ if (!use_atomic_push) {
+ transaction = transaction_begin(&err);
+ if (!transaction) {
+ char *str = xstrdup(err.buf);
+
+ strbuf_release(&err);
+ transaction_free(transaction);
+ rp_error("%s", str);
+ return str;
+ }
+ }
+ if (transaction_update_sha1(transaction, namespaced_name,
new_sha1, old_sha1, 0, 1, "push",
- &err) ||
- transaction_commit(transaction, &err)) {
- char *str = strbuf_detach(&err, NULL);
- transaction_free(transaction);
+ &err)) {
+ char *str = xstrdup(err.buf);
+ strbuf_release(&err);
+ transaction_free(transaction);
rp_error("%s", str);
return str;
}
+ if (!use_atomic_push && transaction_commit(transaction, &err)) {
+ char *str = xstrdup(err.buf);
+ strbuf_release(&err);
+ transaction_free(transaction);
+ rp_error("%s", str);
+ return str;
+ }
transaction_free(transaction);
strbuf_release(&err);
return NULL; /* good */
@@ -810,6 +824,16 @@ static void execute_commands(struct command *commands,
return;
}
+ if (use_atomic_push) {
+ transaction = transaction_begin(&err);
+ if (!transaction) {
+ error("%s", err.buf);
+ strbuf_release(&err);
+ for (cmd = commands; cmd; cmd = cmd->next)
+ cmd->error_string = "transaction error";
+ return;
+ }
+ }
data.cmds = commands;
data.si = si;
if (check_everything_connected(iterate_receive_command_list, 0, &data))
@@ -848,6 +872,14 @@ static void execute_commands(struct command *commands,
}
}
+ if (use_atomic_push) {
+ if (transaction_commit(transaction, &err)) {
+ rp_error("%s", err.buf);
+ for (cmd = commands; cmd; cmd = cmd->next)
+ cmd->error_string = err.buf;
+ }
+ transaction_free(transaction);
+ }
if (shallow_update && !checked_connectivity)
error("BUG: run 'git fsck' for safety.\n"
"If there are errors, try to remove "
@@ -1250,5 +1282,6 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
sha1_array_clear(&shallow);
sha1_array_clear(&ref);
free_commands(commands);
+ strbuf_release(&err);
return 0;
}
--
2.0.1.528.gd0e7a84
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