connect: in ref advertisement, shallows are last
Currently, get_remote_heads() parses the ref advertisement in one loop, allowing refs and shallow lines to intersperse, despite this not being allowed by the specification. Refactor get_remote_heads() to use two loops instead, enforcing that refs come first, and then shallows. This also makes it easier to teach get_remote_heads() to interpret other lines in the ref advertisement, which will be done in a subsequent patch. As part of this change, this patch interprets capabilities only on the first line in the ref advertisement, printing a warning message when encountering capabilities on other lines. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jonathan Tan committed
Sep 26, 2017 at 16:56 UTC
0cd83283dfd2a22b3f95cbee6eaef196e6bde77d
1 file changed
+123
-66
connect.c
+123
-66
@@ -11,6 +11,7 @@
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#include "string-list.h"
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#include "sha1-array.h"
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#include "transport.h"
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+#include "strbuf.h"
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static char *server_capabilities;
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static const char *parse_feature_value(const char *, const char *, int *);
@@ -107,6 +108,104 @@ static void annotate_refs_with_symref_info(struct ref *ref)
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string_list_clear(&symref, 0);
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}
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+/*
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+ * Read one line of a server's ref advertisement into packet_buffer.
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+ */
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+static int read_remote_ref(int in, char **src_buf, size_t *src_len,
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+ int *responded)
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+{
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+ int len = packet_read(in, src_buf, src_len,
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+ packet_buffer, sizeof(packet_buffer),
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+ PACKET_READ_GENTLE_ON_EOF |
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+ PACKET_READ_CHOMP_NEWLINE);
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+ const char *arg;
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+ if (len < 0)
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+ die_initial_contact(*responded);
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+ if (len > 4 && skip_prefix(packet_buffer, "ERR ", &arg))
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+ die("remote error: %s", arg);
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+
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+ *responded = 1;
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+
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+ return len;
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+}
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+
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+#define EXPECTING_FIRST_REF 0
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+#define EXPECTING_REF 1
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+#define EXPECTING_SHALLOW 2
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+
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+static void process_capabilities(int *len)
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+{
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+ int nul_location = strlen(packet_buffer);
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+ if (nul_location == *len)
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+ return;
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+ server_capabilities = xstrdup(packet_buffer + nul_location + 1);
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+ *len = nul_location;
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+}
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+
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+static int process_dummy_ref(void)
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+{
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+ struct object_id oid;
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+ const char *name;
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+
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+ if (parse_oid_hex(packet_buffer, &oid, &name))
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+ return 0;
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+ if (*name != ' ')
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+ return 0;
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+ name++;
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+
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+ return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
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+}
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+
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+static void check_no_capabilities(int len)
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+{
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+ if (strlen(packet_buffer) != len)
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+ warning("Ignoring capabilities after first line '%s'",
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+ packet_buffer + strlen(packet_buffer));
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+}
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+
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+static int process_ref(int len, struct ref ***list, unsigned int flags,
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+ struct oid_array *extra_have)
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+{
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+ struct object_id old_oid;
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+ const char *name;
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+
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+ if (parse_oid_hex(packet_buffer, &old_oid, &name))
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+ return 0;
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+ if (*name != ' ')
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+ return 0;
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+ name++;
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+
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+ if (extra_have && !strcmp(name, ".have")) {
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+ oid_array_append(extra_have, &old_oid);
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+ } else if (!strcmp(name, "capabilities^{}")) {
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+ die("protocol error: unexpected capabilities^{}");
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+ } else if (check_ref(name, flags)) {
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+ struct ref *ref = alloc_ref(name);
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+ oidcpy(&ref->old_oid, &old_oid);
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+ **list = ref;
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+ *list = &ref->next;
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+ }
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+ check_no_capabilities(len);
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+ return 1;
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+}
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+
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+static int process_shallow(int len, struct oid_array *shallow_points)
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+{
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+ const char *arg;
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+ struct object_id old_oid;
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+
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+ if (!skip_prefix(packet_buffer, "shallow ", &arg))
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+ return 0;
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+
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+ if (get_oid_hex(arg, &old_oid))
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+ die("protocol error: expected shallow sha-1, got '%s'", arg);
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+ if (!shallow_points)
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+ die("repository on the other end cannot be shallow");
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+ oid_array_append(shallow_points, &old_oid);
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+ check_no_capabilities(len);
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+ return 1;
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+}
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+
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/*
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* Read all the refs from the other end
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*/
@@ -123,76 +222,34 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
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* willing to talk to us. A hang-up before seeing any
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* response does not necessarily mean an ACL problem, though.
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*/
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- int saw_response;
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- int got_dummy_ref_with_capabilities_declaration = 0;
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+ int responded = 0;
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+ int len;
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+ int state = EXPECTING_FIRST_REF;
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*list = NULL;
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- for (saw_response = 0; ; saw_response = 1) {
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- struct ref *ref;
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- struct object_id old_oid;
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- char *name;
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- int len, name_len;
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- char *buffer = packet_buffer;
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- const char *arg;
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-
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- len = packet_read(in, &src_buf, &src_len,
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- packet_buffer, sizeof(packet_buffer),
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- PACKET_READ_GENTLE_ON_EOF |
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- PACKET_READ_CHOMP_NEWLINE);
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- if (len < 0)
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- die_initial_contact(saw_response);
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-
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- if (!len)
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- break;
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-
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- if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
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- die("remote error: %s", arg);
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-
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- if (len == GIT_SHA1_HEXSZ + strlen("shallow ") &&
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- skip_prefix(buffer, "shallow ", &arg)) {
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- if (get_oid_hex(arg, &old_oid))
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- die("protocol error: expected shallow sha-1, got '%s'", arg);
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- if (!shallow_points)
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- die("repository on the other end cannot be shallow");
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- oid_array_append(shallow_points, &old_oid);
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- continue;
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- }
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- if (len < GIT_SHA1_HEXSZ + 2 || get_oid_hex(buffer, &old_oid) ||
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- buffer[GIT_SHA1_HEXSZ] != ' ')
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- die("protocol error: expected sha/ref, got '%s'", buffer);
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- name = buffer + GIT_SHA1_HEXSZ + 1;
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-
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- name_len = strlen(name);
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- if (len != name_len + GIT_SHA1_HEXSZ + 1) {
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- free(server_capabilities);
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- server_capabilities = xstrdup(name + name_len + 1);
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- }
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-
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- if (extra_have && !strcmp(name, ".have")) {
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- oid_array_append(extra_have, &old_oid);
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- continue;
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- }
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-
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- if (!strcmp(name, "capabilities^{}")) {
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- if (saw_response)
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- die("protocol error: unexpected capabilities^{}");
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- if (got_dummy_ref_with_capabilities_declaration)
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- die("protocol error: multiple capabilities^{}");
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- got_dummy_ref_with_capabilities_declaration = 1;
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- continue;
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+ while ((len = read_remote_ref(in, &src_buf, &src_len, &responded))) {
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+ switch (state) {
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+ case EXPECTING_FIRST_REF:
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+ process_capabilities(&len);
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+ if (process_dummy_ref()) {
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+ state = EXPECTING_SHALLOW;
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+ break;
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+ }
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+ state = EXPECTING_REF;
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+ /* fallthrough */
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+ case EXPECTING_REF:
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+ if (process_ref(len, &list, flags, extra_have))
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+ break;
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+ state = EXPECTING_SHALLOW;
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+ /* fallthrough */
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+ case EXPECTING_SHALLOW:
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+ if (process_shallow(len, shallow_points))
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+ break;
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+ die("protocol error: unexpected '%s'", packet_buffer);
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+ default:
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+ die("unexpected state %d", state);
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}
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-
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- if (!check_ref(name, flags))
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- continue;
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-
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- if (got_dummy_ref_with_capabilities_declaration)
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- die("protocol error: unexpected ref after capabilities^{}");
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-
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- ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1);
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- oidcpy(&ref->old_oid, &old_oid);
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- *list = ref;
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- list = &ref->next;
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}
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annotate_refs_with_symref_info(*orig_list);