Teach upload-pack and receive-pack to omit some refs from their
initial advertisements by paying attention to the transfer.hiderefs
multi-valued configuration variable. Any ref that is under the
hierarchies listed on the value of this variable is excluded from
responses to requests made by "ls-remote", "fetch", "clone", "push",
etc.
A typical use case may be
[transfer]
hiderefs = refs/pull
to hide the refs that are internally used by the hosting site and
should not be exposed over the network.
Because these hidden refs do not count as OUR_REF, an attempt to
fetch objects at the tip of them will be rejected, and because these
refs do not get advertised, "git push :" will not see local branches
that have the same name as them as "matching" ones to be sent.
An attempt to update/delete these hidden refs with an explicit
refspec, e.g. "git push origin :refs/pull/11/head", is rejected.
This is not a new restriction. To the pusher, it would appear that
there is no such ref, so its push request will conclude with "Now
that I sent you all the data, it is time for you to update the refs.
I saw that the ref did not exist when I started pushing, and I want
the result to point at this commit". The receiving end will apply
the compare-and-swap rule to this request and rejects the push with
"Well, your update request conflicts with somebody else; I see there
is such a ref.", which is the right thing to do. Otherwise a push to
a hidden ref will always be "the last one wins", which is not a good
default.
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
Documentation/config.txt | 11 +++++++++++
builtin/receive-pack.c | 24 ++++++++++++++++++++++++
refs.c | 41 +++++++++++++++++++++++++++++++++++++++++
refs.h | 3 +++
t/t5512-ls-remote.sh | 9 +++++++++
t/t5516-fetch-push.sh | 24 ++++++++++++++++++++++++
upload-pack.c | 14 +++++++++++++-
7 files changed, 125 insertions(+), 1 deletion(-)
diff --git a/Documentation/config.txt b/Documentation/config.txt
index ef45c99..f57c802 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2057,6 +2057,17 @@ transfer.fsckObjects::
not set, the value of this variable is used instead.
Defaults to false.
+transfer.hiderefs::
+ String(s) `upload-pack` and `receive-pack` use to decide
+ which refs to omit from their initial advertisement. Use
+ more than one transfer.hiderefs configuration variables to
+ specify multiple prefix strings. A ref that are under the
+ hierarchies listed on the value of this variable is excluded,
+ and is hidden from `git ls-remote`, `git fetch`, `git push :`,
+ etc. An attempt to update or delete a hidden ref by `git push`
+ is rejected, and an attempt to fetch a hidden ref by `git fetch`
+ will fail.
+
transfer.unpackLimit::
When `fetch.unpackLimit` or `receive.unpackLimit` are
not set, the value of this variable is used instead.
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index ff781fe..a8248d9 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -59,6 +59,11 @@ static enum deny_action parse_deny_action(const char *var, const char *value)
static int receive_pack_config(const char *var, const char *value, void *cb)
{
+ int status = parse_hide_refs_config(var, value, cb);
+
+ if (status)
+ return status;
+
if (strcmp(var, "receive.denydeletes") == 0) {
deny_deletes = git_config_bool(var, value);
return 0;
@@ -119,6 +124,9 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
static void show_ref(const char *path, const unsigned char *sha1)
{
+ if (ref_is_hidden(path))
+ return;
+
if (sent_capabilities)
packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
else
@@ -688,6 +696,20 @@ static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])
return -1; /* end of list */
}
+static void reject_updates_to_hidden(struct command *commands)
+{
+ struct command *cmd;
+
+ for (cmd = commands; cmd; cmd = cmd->next) {
+ if (cmd->error_string || !ref_is_hidden(cmd->ref_name))
+ continue;
+ if (is_null_sha1(cmd->new_sha1))
+ cmd->error_string = "deny deleting a hidden ref";
+ else
+ cmd->error_string = "deny updating a hidden ref";
+ }
+}
+
static void execute_commands(struct command *commands, const char *unpacker_error)
{
struct command *cmd;
@@ -704,6 +726,8 @@ static void execute_commands(struct command *commands, const char *unpacker_erro
0, &cmd))
set_connectivity_errors(commands);
+ reject_updates_to_hidden(commands);
+
if (run_receive_hook(commands, pre_receive_hook, 0)) {
for (cmd = commands; cmd; cmd = cmd->next) {
if (!cmd->error_string)
diff --git a/refs.c b/refs.c
index 541fec2..e3574ca 100644
--- a/refs.c
+++ b/refs.c
@@ -3,6 +3,7 @@
#include "object.h"
#include "tag.h"
#include "dir.h"
+#include "string-list.h"
/*
* Make sure "ref" is something reasonable to have under ".git/refs/";
@@ -2556,3 +2557,43 @@ char *shorten_unambiguous_ref(const char *refname, int strict)
free(short_name);
return xstrdup(refname);
}
+
+static struct string_list *hide_refs;
+
+int parse_hide_refs_config(const char *var, const char *value, void *unused)
+{
+ if (!strcmp("transfer.hiderefs", var)) {
+ char *ref;
+ int len;
+
+ if (!value)
+ return config_error_nonbool(var);
+ ref = xstrdup(value);
+ len = strlen(ref);
+ while (len && ref[len - 1] == '/')
+ ref[--len] = '\0';
+ if (!hide_refs) {
+ hide_refs = xcalloc(1, sizeof(*hide_refs));
+ hide_refs->strdup_strings = 1;
+ }
+ string_list_append(hide_refs, ref);
+ }
+ return 0;
+}
+
+int ref_is_hidden(const char *refname)
+{
+ struct string_list_item *item;
+
+ if (!hide_refs)
+ return 0;
+ for_each_string_list_item(item, hide_refs) {
+ int len;
+ if (prefixcmp(refname, item->string))
+ continue;
+ len = strlen(item->string);
+ if (!refname[len] || refname[len] == '/')
+ return 1;
+ }
+ return 0;
+}
diff --git a/refs.h b/refs.h
index d6c2fe2..50b233f 100644
--- a/refs.h
+++ b/refs.h
@@ -147,4 +147,7 @@ int update_ref(const char *action, const char *refname,
const unsigned char *sha1, const unsigned char *oldval,
int flags, enum action_on_err onerr);
+extern int parse_hide_refs_config(const char *var, const char *value, void *);
+extern int ref_is_hidden(const char *);
+
#endif /* REFS_H */
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index d16e5d3..d0702ed 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -126,4 +126,13 @@ test_expect_success 'Report match with --exit-code' '
test_cmp expect actual
'
+test_expect_success 'Hide some refs' '
+ test_config transfer.hiderefs refs/tags &&
+ git ls-remote . >actual &&
+ test_unconfig transfer.hiderefs &&
+ git ls-remote . |
+ sed -e "/ refs\/tags\//d" >expect &&
+ test_cmp expect actual
+'
+
test_done
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 6009372..852efb6 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1037,4 +1037,28 @@ test_expect_success 'push --prune refspec' '
! check_push_result $the_first_commit tmp/foo tmp/bar
'
+test_expect_success 'push to update a hidden ref' '
+ mk_test heads/master hidden/one hidden/two hidden/three &&
+ (
+ cd testrepo &&
+ git config transfer.hiderefs refs/hidden
+ ) &&
+
+ # push to unhidden ref succeeds normally
+ git push testrepo master:refs/heads/master &&
+ check_push_result $the_commit heads/master &&
+
+ # push to update a hidden ref should fail
+ test_must_fail git push testrepo master:refs/hidden/one &&
+ check_push_result $the_first_commit hidden/one &&
+
+ # push to delete a hidden ref should fail
+ test_must_fail git push testrepo :refs/hidden/two &&
+ check_push_result $the_first_commit hidden/two &&
+
+ # idempotent push to update a hidden ref should fail
+ test_must_fail git push testrepo $the_first_commit:refs/hidden/three &&
+ check_push_result $the_first_commit hidden/three
+'
+
test_done
diff --git a/upload-pack.c b/upload-pack.c
index 3a26a7b..6b10843 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -12,6 +12,7 @@
#include "run-command.h"
#include "sigchain.h"
#include "version.h"
+#include "string-list.h"
static const char upload_pack_usage[] = "git upload-pack [--strict] [--timeout=<n>] <dir>";
@@ -719,9 +720,13 @@ static void receive_needs(void)
free(shallows.objects);
}
+/* return non-zero if the ref is hidden, otherwise 0 */
static int mark_our_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
struct object *o = lookup_unknown_object(sha1);
+
+ if (ref_is_hidden(refname))
+ return 1;
if (!o)
die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
o->flags |= OUR_REF;
@@ -736,7 +741,8 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
const char *refname_nons = strip_namespace(refname);
unsigned char peeled[20];
- mark_our_ref(refname, sha1, flag, cb_data);
+ if (mark_our_ref(refname, sha1, flag, cb_data))
+ return 0;
if (capabilities)
packet_write(1, "%s %s%c%s%s agent=%s\n",
@@ -773,6 +779,11 @@ static void upload_pack(void)
}
}
+static int upload_pack_config(const char *var, const char *value, void *unused)
+{
+ return parse_hide_refs_config(var, value, unused);
+}
+
int main(int argc, char **argv)
{
char *dir;
@@ -824,6 +835,7 @@ int main(int argc, char **argv)
die("'%s' does not appear to be a git repository", dir);
if (is_repository_shallow())
die("attempt to fetch/clone from a shallow repository");
+ git_config(upload_pack_config, NULL);
if (getenv("GIT_DEBUG_SEND_PACK"))
debug_fd = atoi(getenv("GIT_DEBUG_SEND_PACK"));
upload_pack();
--
1.8.1.2.589.ga9b91ac
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