promisor-remote: remove fetch_if_missing=0
Commit 6462d5eb9a ("fetch: remove fetch_if_missing=0", 2019-11-08) strove to remove the need for fetch_if_missing=0 from the fetching mechanism, so it is plausible to attempt removing fetch_if_missing=0 from the lazy-fetching mechanism in promisor-remote as well. But doing so reveals a bug - when the server does not send an object pointed to by a tag object, an infinite loop occurs: Git attempts to fetch the missing object, which causes a deferencing of all refs (for negotiation), which causes a lazy fetch of that missing object, and so on. This bug is because of unnecessary use of the fetch negotiator during lazy fetching - it is not used after initialization, but it is still initialized (which causes the dereferencing of all refs). Thus, when the negotiator is not used during fetching, refrain from initializing it. Then, remove fetch_if_missing from promisor-remote. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jonathan Tan committed
Nov 12, 2019 at 16:34 UTC
603960b50edeb1f0afa694f2f0283e553c031129
2 files changed
+32
-17
fetch-pack.c
+32
-14
@@ -896,8 +896,15 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
896
struct object_id oid;
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const char *agent_feature;
898
int agent_len;
899
- struct fetch_negotiator negotiator;
900
- fetch_negotiator_init(r, &negotiator);
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+ struct fetch_negotiator negotiator_alloc;
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+ struct fetch_negotiator *negotiator;
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+
902
+ if (args->no_dependents) {
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+ negotiator = NULL;
904
+ } else {
905
+ negotiator = &negotiator_alloc;
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+ fetch_negotiator_init(r, negotiator);
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+ }
908
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sort_ref_list(&ref, ref_compare_name);
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QSORT(sought, nr_sought, cmp_ref_by_name);
@@ -984,7 +991,7 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
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die(_("Server does not support --deepen"));
992
993
if (!args->no_dependents) {
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- mark_complete_and_common_ref(&negotiator, args, &ref);
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+ mark_complete_and_common_ref(negotiator, args, &ref);
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filter_refs(args, &ref, sought, nr_sought);
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if (everything_local(args, &ref)) {
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packet_flush(fd[1]);
@@ -993,7 +1000,7 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
1000
} else {
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filter_refs(args, &ref, sought, nr_sought);
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}
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- if (find_common(&negotiator, args, fd, &oid, ref) < 0)
1003
+ if (find_common(negotiator, args, fd, &oid, ref) < 0)
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if (!args->keep_pack)
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/* When cloning, it is not unusual to have
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* no common commit.
@@ -1013,7 +1020,8 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
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die(_("git fetch-pack: fetch failed."));
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1022
all_done:
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- negotiator.release(&negotiator);
1023
+ if (negotiator)
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+ negotiator->release(negotiator);
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return ref;
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}
1027
@@ -1231,7 +1239,8 @@ static int process_acks(struct fetch_negotiator *negotiator,
1239
struct commit *commit;
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oidset_insert(common, &oid);
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commit = lookup_commit(the_repository, &oid);
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- negotiator->ack(negotiator, commit);
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+ if (negotiator)
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+ negotiator->ack(negotiator, commit);
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}
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continue;
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}
@@ -1383,8 +1392,16 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
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struct packet_reader reader;
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int in_vain = 0, negotiation_started = 0;
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int haves_to_send = INITIAL_FLUSH;
1386
- struct fetch_negotiator negotiator;
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- fetch_negotiator_init(r, &negotiator);
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+ struct fetch_negotiator negotiator_alloc;
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+ struct fetch_negotiator *negotiator;
1397
+
1398
+ if (args->no_dependents) {
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+ negotiator = NULL;
1400
+ } else {
1401
+ negotiator = &negotiator_alloc;
1402
+ fetch_negotiator_init(r, negotiator);
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+ }
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+
1405
packet_reader_init(&reader, fd[0], NULL, 0,
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PACKET_READ_CHOMP_NEWLINE |
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PACKET_READ_DIE_ON_ERR_PACKET);
@@ -1408,15 +1425,15 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1425
1426
/* Filter 'ref' by 'sought' and those that aren't local */
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if (!args->no_dependents) {
1411
- mark_complete_and_common_ref(&negotiator, args, &ref);
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+ mark_complete_and_common_ref(negotiator, args, &ref);
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filter_refs(args, &ref, sought, nr_sought);
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if (everything_local(args, &ref))
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state = FETCH_DONE;
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else
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state = FETCH_SEND_REQUEST;
1434
1418
- mark_tips(&negotiator, args->negotiation_tips);
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- for_each_cached_alternate(&negotiator,
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+ mark_tips(negotiator, args->negotiation_tips);
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+ for_each_cached_alternate(negotiator,
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insert_one_alternate_object);
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} else {
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filter_refs(args, &ref, sought, nr_sought);
@@ -1430,7 +1447,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
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"negotiation_v2",
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the_repository);
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}
1433
- if (send_fetch_request(&negotiator, fd[1], args, ref,
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+ if (send_fetch_request(negotiator, fd[1], args, ref,
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&common,
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&haves_to_send, &in_vain,
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reader.use_sideband))
@@ -1440,7 +1457,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
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break;
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case FETCH_PROCESS_ACKS:
1459
/* Process ACKs/NAKs */
1443
- switch (process_acks(&negotiator, &reader, &common)) {
1460
+ switch (process_acks(negotiator, &reader, &common)) {
1461
case 2:
1462
state = FETCH_GET_PACK;
1463
break;
@@ -1475,7 +1492,8 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1492
}
1493
}
1494
1478
- negotiator.release(&negotiator);
1495
+ if (negotiator)
1496
+ negotiator->release(negotiator);
1497
oidset_clear(&common);
1498
return ref;
1499
}
promisor-remote.c
-3
@@ -16,10 +16,8 @@ static int fetch_refs(const char *remote_name, struct ref *ref)
16
{
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struct remote *remote;
18
struct transport *transport;
19
- int original_fetch_if_missing = fetch_if_missing;
19
int res;
20
22
- fetch_if_missing = 0;
21
remote = remote_get(remote_name);
22
if (!remote->url[0])
23
die(_("Remote with no URL"));
@@ -28,7 +26,6 @@ static int fetch_refs(const char *remote_name, struct ref *ref)
26
transport_set_option(transport, TRANS_OPT_FROM_PROMISOR, "1");
27
transport_set_option(transport, TRANS_OPT_NO_DEPENDENTS, "1");
28
res = transport_fetch_refs(transport, ref);
31
- fetch_if_missing = original_fetch_if_missing;
29
30
return res;
31
}