cache-tree: prefetch in partial clone read-tree
"git read-tree" checks the existence of the blobs referenced by the
given tree, but does not bulk prefetch them. Add a bulk prefetch.
The lack of prefetch here was noticed at $DAYJOB during a merge
involving some specific commits, but I couldn't find a minimal merge
that didn't also trigger the prefetch in check_updates() in
unpack-trees.c (and in all these cases, the lack of prefetch in
cache-tree.c didn't matter because all the relevant blobs would have
already been prefetched by then). This is why I used read-tree here to
exercise this code path.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/cache-tree.c b/cache-tree.c
index 45e5866..9ba2c7c 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -237,6 +237,11 @@ int cache_tree_fully_valid(struct cache_tree *it)
return 1;
}
+static int must_check_existence(const struct cache_entry *ce)
+{
+ return !(has_promisor_remote() && ce_skip_worktree(ce));
+}
+
static int update_one(struct cache_tree *it,
struct cache_entry **cache,
int entries,
@@ -378,8 +383,7 @@ static int update_one(struct cache_tree *it,
}
ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
- (has_promisor_remote() &&
- ce_skip_worktree(ce));
+ !must_check_existence(ce);
if (is_null_oid(oid) ||
(!ce_missing_ok && !has_object_file(oid))) {
strbuf_release(&buffer);
@@ -466,6 +470,9 @@ int cache_tree_update(struct index_state *istate, int flags)
if (!istate->cache_tree)
istate->cache_tree = cache_tree();
+ if (!(flags & WRITE_TREE_MISSING_OK) && has_promisor_remote())
+ prefetch_cache_entries(istate, must_check_existence);
+
trace_performance_enter();
trace2_region_enter("cache_tree", "update", the_repository);
i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
