[PATCH v2 4/7] fetch: only populate existing_refs if needed
From: Jonathan Tan <hidden>
Date: 2020-08-11 22:52:37
Subsystem:
the rest · Maintainer:
Linus Torvalds
When fetching tags, Git only writes tags that do not already exist in the client repository. This necessitates an iteration over all the refs, but fetch performs this iteration even if no tags are fetched. This issue is more severe in a partial clone because the iteration over refs also checks that the targets of those refs are present, necessitating a lazy fetch if the target is missing. Therefore, iterate over the refs only when necessary. The user can avoid this iteration by refraining from fetching tags, for example, by passing --no-tags as an argument. A subsequent patch will also teach Git to use "git fetch" to lazy-fetch missing objects in a partial clone, thus also making use of this change. Signed-off-by: Jonathan Tan <redacted> --- 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; }
--
2.28.0.236.gb10cc79966-goog