From 2aa5ac68046d417aa2c4f92f94503ccb8918d08c Mon Sep 17 00:00:00 2001
From: Adin Schmahmann <adin.schmahmann@gmail.com>
Date: Wed, 26 Aug 2020 13:17:48 -0400
Subject: [PATCH 1/2] ResolveToLastNode no longer fetches nodes it does not
 need

This commit was moved from ipfs/go-path@ac811c4b484b06ea22da1071890e94fb4b7ab9be
---
 path/resolver/resolver.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/path/resolver/resolver.go b/path/resolver/resolver.go
index 67bb9f6fb..9f153840c 100644
--- a/path/resolver/resolver.go
+++ b/path/resolver/resolver.go
@@ -89,6 +89,10 @@ func (r *Resolver) ResolveToLastNode(ctx context.Context, fpath path.Path) (cid.
 			return cid.Cid{}, nil, err
 		}
 
+		if len(rest) == 0 {
+			return lnk.Cid, nil, nil
+		}
+
 		next, err := lnk.GetNode(ctx, r.DAG)
 		if err != nil {
 			return cid.Cid{}, nil, err

From 35e8ffb3dc5c79e7d56367ce8d74bbaa83200aba Mon Sep 17 00:00:00 2001
From: Adin Schmahmann <adin.schmahmann@gmail.com>
Date: Wed, 26 Aug 2020 13:59:39 -0400
Subject: [PATCH 2/2] test: add test that ResolveToLastNode does not perform
 unncessary fetches

This commit was moved from ipfs/go-path@6d87ec04ebe94d4c105b78fe64471ebdb2a26b70
---
 path/resolver/resolver_test.go | 40 ++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/path/resolver/resolver_test.go b/path/resolver/resolver_test.go
index 480ccdf1d..d3c6913e7 100644
--- a/path/resolver/resolver_test.go
+++ b/path/resolver/resolver_test.go
@@ -105,3 +105,43 @@ func TestRecurivePathResolution(t *testing.T) {
 			p.String(), rCid.String(), cKey.String()))
 	}
 }
+
+func TestResolveToLastNode_NoUnnecessaryFetching(t *testing.T) {
+	ctx := context.Background()
+	dagService := dagmock.Mock()
+
+	a := randNode()
+	b := randNode()
+
+	err := a.AddNodeLink("child", b)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = dagService.Add(ctx, a)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	aKey := a.Cid()
+
+	segments := []string{aKey.String(), "child"}
+	p, err := path.FromSegments("/ipfs/", segments...)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	resolver := resolver.NewBasicResolver(dagService)
+	resolvedCID, remainingPath, err := resolver.ResolveToLastNode(ctx, p)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(remainingPath) > 0 {
+		t.Fatal("cannot have remaining path")
+	}
+
+	if !resolvedCID.Equals(b.Cid()) {
+		t.Fatal("resolved to the wrong CID")
+	}
+}