fetch-pack: implement ref-in-want
Implement ref-in-want on the client side so that when a server supports the "ref-in-want" feature, a client will send "want-ref" lines for each reference the client wants to fetch. This feature allows clients to tolerate inconsistencies that exist when a remote repository's refs change during the course of negotiation. This allows a client to request to request a particular ref without specifying the OID of the ref. This means that instead of hitting an error when a ref no longer points at the OID it did at the beginning of negotiation, negotiation can continue and the value of that ref will be sent at the termination of negotiation, just before a packfile is sent. More information on the ref-in-want feature can be found in Documentation/technical/protocol-v2.txt. Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Brandon Williams committed
Jun 27, 2018 at 15:30 UTC
733020517a1baa6f4f76bb7bf48d8d8d14eecd6c
4 files changed
+186
-3
fetch-pack.c
+35
-3
@@ -1102,9 +1102,10 @@ static void add_shallow_requests(struct strbuf *req_buf,
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1103
static void add_wants(const struct ref *wants, struct strbuf *req_buf)
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{
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+ int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
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+
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for ( ; wants ; wants = wants->next) {
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const struct object_id *remote = &wants->old_oid;
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- const char *remote_hex;
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struct object *o;
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/*
@@ -1122,8 +1123,10 @@ static void add_wants(const struct ref *wants, struct strbuf *req_buf)
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continue;
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}
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- remote_hex = oid_to_hex(remote);
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- packet_buf_write(req_buf, "want %s\n", remote_hex);
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+ if (!use_ref_in_want || wants->exact_oid)
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+ packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
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+ else
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+ packet_buf_write(req_buf, "want-ref %s\n", wants->name);
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}
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}
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@@ -1334,6 +1337,32 @@ static void receive_shallow_info(struct fetch_pack_args *args,
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args->deepen = 1;
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}
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+static void receive_wanted_refs(struct packet_reader *reader, struct ref *refs)
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+{
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+ process_section_header(reader, "wanted-refs", 0);
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+ while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
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+ struct object_id oid;
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+ const char *end;
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+ struct ref *r = NULL;
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+
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+ if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
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+ die("expected wanted-ref, got '%s'", reader->line);
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+
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+ for (r = refs; r; r = r->next) {
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+ if (!strcmp(end, r->name)) {
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+ oidcpy(&r->old_oid, &oid);
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+ break;
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+ }
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+ }
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+
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+ if (!r)
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+ die("unexpected wanted-ref: '%s'", reader->line);
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+ }
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+
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+ if (reader->status != PACKET_READ_DELIM)
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+ die("error processing wanted refs: %d", reader->status);
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+}
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+
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enum fetch_state {
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FETCH_CHECK_LOCAL = 0,
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FETCH_SEND_REQUEST,
@@ -1408,6 +1437,9 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
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if (process_section_header(&reader, "shallow-info", 1))
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receive_shallow_info(args, &reader);
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+ if (process_section_header(&reader, "wanted-refs", 1))
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+ receive_wanted_refs(&reader, ref);
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+
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/* get the pack */
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process_section_header(&reader, "packfile", 0);
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if (get_pack(args, fd, pack_lockfile))
remote.c
+1
@@ -1735,6 +1735,7 @@ int get_fetch_map(const struct ref *remote_refs,
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if (refspec->exact_sha1) {
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ref_map = alloc_ref(name);
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get_oid_hex(name, &ref_map->old_oid);
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+ ref_map->exact_oid = 1;
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} else {
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ref_map = get_remote_ref(remote_refs, name);
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}
remote.h
+1
@@ -73,6 +73,7 @@ struct ref {
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force:1,
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forced_update:1,
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expect_old_sha1:1,
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+ exact_oid:1,
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deletion:1;
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enum {
t/t5703-upload-pack-ref-in-want.sh
+149
@@ -211,6 +211,18 @@ test_expect_success 'server is initially ahead - no ref in want' '
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grep "ERR upload-pack: not our ref" err
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'
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+test_expect_success 'server is initially ahead - ref in want' '
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+ git -C "$REPO" config uploadpack.allowRefInWant true &&
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ inconsistency master 1234567890123456789012345678901234567890 &&
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+ git -C local fetch &&
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+
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+ git -C "$REPO" rev-parse --verify master >expected &&
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+ git -C local rev-parse --verify refs/remotes/origin/master >actual &&
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+ test_cmp expected actual
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+'
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+
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test_expect_success 'server is initially behind - no ref in want' '
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git -C "$REPO" config uploadpack.allowRefInWant false &&
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rm -rf local &&
@@ -223,6 +235,143 @@ test_expect_success 'server is initially behind - no ref in want' '
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test_cmp expected actual
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'
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+test_expect_success 'server is initially behind - ref in want' '
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+ git -C "$REPO" config uploadpack.allowRefInWant true &&
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ inconsistency master "master^" &&
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+ git -C local fetch &&
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+
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+ git -C "$REPO" rev-parse --verify "master" >expected &&
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+ git -C local rev-parse --verify refs/remotes/origin/master >actual &&
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+ test_cmp expected actual
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+'
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+
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+test_expect_success 'server loses a ref - ref in want' '
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+ git -C "$REPO" config uploadpack.allowRefInWant true &&
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ echo "s/master/raster/" >"$HTTPD_ROOT_PATH/one-time-sed" &&
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+ test_must_fail git -C local fetch 2>err &&
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+
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+ grep "ERR unknown ref refs/heads/raster" err
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+'
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+
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stop_httpd
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+REPO="$(pwd)/repo"
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+LOCAL_PRISTINE="$(pwd)/local_pristine"
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+
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+# $REPO
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+# c(o/foo) d(o/bar)
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+# \ /
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+# b e(baz) f(master)
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+# \__ | __/
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+# \ | /
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+# a
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+#
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+# $LOCAL_PRISTINE
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+# s32(side)
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+# |
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+# .
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+# .
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+# |
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+# a(master)
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+test_expect_success 'setup repos for fetching with ref-in-want tests' '
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+ (
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+ git init "$REPO" &&
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+ cd "$REPO" &&
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+ test_commit a &&
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+
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+ # Local repo with many commits (so that negotiation will take
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+ # more than 1 request/response pair)
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+ rm -rf "$LOCAL_PRISTINE" &&
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+ git clone "file://$REPO" "$LOCAL_PRISTINE" &&
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+ cd "$LOCAL_PRISTINE" &&
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+ git checkout -b side &&
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+ for i in $(seq 1 33); do test_commit s$i; done &&
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+
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+ # Add novel commits to upstream
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+ git checkout master &&
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+ cd "$REPO" &&
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+ git checkout -b o/foo &&
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+ test_commit b &&
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+ test_commit c &&
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+ git checkout -b o/bar b &&
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+ test_commit d &&
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+ git checkout -b baz a &&
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+ test_commit e &&
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+ git checkout master &&
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+ test_commit f
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+ ) &&
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+ git -C "$REPO" config uploadpack.allowRefInWant true &&
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+ git -C "$LOCAL_PRISTINE" config protocol.version 2
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+'
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+
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+test_expect_success 'fetching with exact OID' '
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+ test_when_finished "rm -f log" &&
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+
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ GIT_TRACE_PACKET="$(pwd)/log" git -C local fetch origin \
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+ $(git -C "$REPO" rev-parse d):refs/heads/actual &&
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+
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+ git -C "$REPO" rev-parse "d" >expected &&
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+ git -C local rev-parse refs/heads/actual >actual &&
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+ test_cmp expected actual &&
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+ grep "want $(git -C "$REPO" rev-parse d)" log
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+'
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+
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+test_expect_success 'fetching multiple refs' '
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+ test_when_finished "rm -f log" &&
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+
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ GIT_TRACE_PACKET="$(pwd)/log" git -C local fetch origin master baz &&
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+
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+ git -C "$REPO" rev-parse "master" "baz" >expected &&
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+ git -C local rev-parse refs/remotes/origin/master refs/remotes/origin/baz >actual &&
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+ test_cmp expected actual &&
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+ grep "want-ref refs/heads/master" log &&
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+ grep "want-ref refs/heads/baz" log
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+'
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+
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+test_expect_success 'fetching ref and exact OID' '
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+ test_when_finished "rm -f log" &&
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+
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ GIT_TRACE_PACKET="$(pwd)/log" git -C local fetch origin \
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+ master $(git -C "$REPO" rev-parse b):refs/heads/actual &&
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+
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+ git -C "$REPO" rev-parse "master" "b" >expected &&
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+ git -C local rev-parse refs/remotes/origin/master refs/heads/actual >actual &&
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+ test_cmp expected actual &&
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+ grep "want $(git -C "$REPO" rev-parse b)" log &&
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+ grep "want-ref refs/heads/master" log
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+'
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+
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+test_expect_success 'fetching with wildcard that does not match any refs' '
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+ test_when_finished "rm -f log" &&
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+
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ git -C local fetch origin refs/heads/none*:refs/heads/* >out &&
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+ test_must_be_empty out
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+'
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+
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+test_expect_success 'fetching with wildcard that matches multiple refs' '
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+ test_when_finished "rm -f log" &&
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+
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+ rm -rf local &&
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+ cp -r "$LOCAL_PRISTINE" local &&
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+ GIT_TRACE_PACKET="$(pwd)/log" git -C local fetch origin refs/heads/o*:refs/heads/o* &&
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+
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+ git -C "$REPO" rev-parse "o/foo" "o/bar" >expected &&
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+ git -C local rev-parse "o/foo" "o/bar" >actual &&
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+ test_cmp expected actual &&
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+ grep "want-ref refs/heads/o/foo" log &&
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+ grep "want-ref refs/heads/o/bar" log
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+'
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+
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test_done