From: Jonathan Tan <jonathantanmy@google.com> To: git@vger.kernel.org Cc: Jonathan Tan <jonathantanmy@google.com>, stolee@gmail.com, gitster@pobox.com Subject: [PATCH v3 4/7] fetch: only populate existing_refs if needed Date: Mon, 17 Aug 2020 21:01:34 -0700 [thread overview] Message-ID: <a5554cd27f8aac5018e5699837e3b9e9badcd3a4.1597722942.git.jonathantanmy@google.com> (raw) In-Reply-To: <cover.1597722941.git.jonathantanmy@google.com> In "fetch", get_ref_map() iterates over all refs to populate "existing_refs" in order to populate peer_ref->old_oid in the returned refmap, even if the refmap has no peer_ref set - which is the case when only literal hashes (i.e. no refs by name) are fetched. Iterating over refs causes the targets of those refs to be checked for existence. Avoiding this is especially important when we use "git fetch" to perform lazy fetches in a partial clone because a target of such a ref may need to be itself lazy-fetched (and otherwise causing an infinite loop). Therefore, avoid populating "existing_refs" until necessary. With this patch, because Git lazy-fetches objects by literal hashes (to be done in a subsequent commit), it will then be able to guarantee avoiding reading targets of refs. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> --- builtin/fetch.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/builtin/fetch.c b/builtin/fetch.c index 29db219c68..6460ce3f4e 100644 --- a/builtin/fetch.c +++ b/builtin/fetch.c @@ -449,6 +449,7 @@ static struct ref *get_ref_map(struct remote *remote, struct ref *orefs = NULL, **oref_tail = &orefs; struct hashmap existing_refs; + int existing_refs_populated = 0; if (rs->nr) { struct refspec *fetch_refspec; @@ -542,15 +543,18 @@ static struct ref *get_ref_map(struct remote *remote, ref_map = ref_remove_duplicates(ref_map); - refname_hash_init(&existing_refs); - for_each_ref(add_one_refname, &existing_refs); - for (rm = ref_map; rm; rm = rm->next) { if (rm->peer_ref) { const char *refname = rm->peer_ref->name; struct refname_hash_entry *peer_item; unsigned int hash = strhash(refname); + if (!existing_refs_populated) { + refname_hash_init(&existing_refs); + for_each_ref(add_one_refname, &existing_refs); + existing_refs_populated = 1; + } + peer_item = hashmap_get_entry_from_hash(&existing_refs, hash, refname, struct refname_hash_entry, ent); @@ -560,7 +564,8 @@ static struct ref *get_ref_map(struct remote *remote, } } } - hashmap_free_entries(&existing_refs, struct refname_hash_entry, ent); + if (existing_refs_populated) + hashmap_free_entries(&existing_refs, struct refname_hash_entry, ent); return ref_map; } -- 2.28.0.220.ged08abb693-goog
next prev parent reply other threads:[~2020-08-18 4:02 UTC|newest] Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-24 22:38 [RFC PATCH] Modify fetch-pack to no longer die on error? Jonathan Tan 2020-07-24 23:07 ` Junio C Hamano 2020-07-24 23:11 ` Junio C Hamano 2020-07-25 21:41 ` Jeff King 2020-07-25 23:01 ` Junio C Hamano 2020-07-27 17:11 ` Jeff King 2020-07-28 19:23 ` Jonathan Tan 2020-07-28 20:08 ` Jeff King 2020-07-29 18:53 ` Jonathan Tan 2020-07-29 19:29 ` Jeff King 2020-07-29 19:02 ` Junio C Hamano 2020-07-29 22:55 ` Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 0/7] Lazy fetch with subprocess Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 1/7] fetch-pack: allow NULL negotiator->add_tip Jonathan Tan 2020-08-05 19:53 ` Junio C Hamano 2020-08-07 20:53 ` Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 2/7] fetch-pack: allow NULL negotiator->known_common Jonathan Tan 2020-08-05 20:08 ` Junio C Hamano 2020-08-05 22:11 ` Junio C Hamano 2020-08-07 20:59 ` Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 3/7] negotiator/null: add null fetch negotiator Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 4/7] fetch: --stdin Jonathan Tan 2020-08-05 20:33 ` Junio C Hamano 2020-08-07 21:10 ` Jonathan Tan 2020-08-07 21:58 ` Junio C Hamano 2020-08-07 21:10 ` Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 5/7] fetch: submodule config Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 6/7] fetch: only populate existing_refs if needed Jonathan Tan 2020-08-05 1:20 ` [RFC PATCH 7/7] promisor-remote: use subprocess to fetch Jonathan Tan 2020-08-11 22:52 ` [PATCH v2 0/7] Lazy fetch with subprocess Jonathan Tan 2020-08-11 22:52 ` [PATCH v2 1/7] negotiator/null: add null fetch negotiator Jonathan Tan 2020-08-12 12:55 ` Derrick Stolee 2020-08-12 16:44 ` Junio C Hamano 2020-08-12 17:29 ` Jonathan Tan 2020-08-11 22:52 ` [PATCH v2 2/7] fetch: allow refspecs specified through stdin Jonathan Tan 2020-08-11 22:52 ` [PATCH v2 3/7] fetch: avoid reading submodule config until needed Jonathan Tan 2020-08-12 17:34 ` Junio C Hamano 2020-08-11 22:52 ` [PATCH v2 4/7] fetch: only populate existing_refs if needed Jonathan Tan 2020-08-12 18:06 ` Junio C Hamano 2020-08-11 22:52 ` [PATCH v2 5/7] fetch-pack: do not lazy-fetch during ref iteration Jonathan Tan 2020-08-12 18:25 ` Junio C Hamano 2020-08-11 22:52 ` [PATCH v2 6/7] promisor-remote: lazy-fetch objects in subprocess Jonathan Tan 2020-08-12 18:28 ` Junio C Hamano 2020-08-11 22:52 ` [PATCH v2 7/7] fetch-pack: remove no_dependents code Jonathan Tan 2020-08-12 12:51 ` [PATCH v2 0/7] Lazy fetch with subprocess Derrick Stolee 2020-08-18 4:01 ` [PATCH v3 " Jonathan Tan 2020-08-18 4:01 ` [PATCH v3 1/7] negotiator/noop: add noop fetch negotiator Jonathan Tan 2020-08-18 4:01 ` [PATCH v3 2/7] fetch: allow refspecs specified through stdin Jonathan Tan 2020-08-18 4:01 ` [PATCH v3 3/7] fetch: avoid reading submodule config until needed Jonathan Tan 2020-08-18 4:01 ` Jonathan Tan [this message] 2020-08-18 4:01 ` [PATCH v3 5/7] fetch-pack: do not lazy-fetch during ref iteration Jonathan Tan 2020-08-18 4:01 ` [PATCH v3 6/7] promisor-remote: lazy-fetch objects in subprocess Jonathan Tan 2020-08-18 4:01 ` [PATCH v3 7/7] fetch-pack: remove no_dependents code Jonathan Tan 2020-08-18 19:56 ` [PATCH v3 0/7] Lazy fetch with subprocess Junio C Hamano 2020-08-18 22:32 ` Junio C Hamano 2020-08-18 23:36 ` [PATCH] fixup! promisor-remote: lazy-fetch objects in subprocess Jonathan Tan 2020-08-18 23:57 ` Junio C Hamano
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