swarm/api: Fix adding paths which exist as manifests (#14482)

Signed-off-by: Lewis Marshall <lewis@lmars.net>

swarm/api/manifest_test.go

@@ -18,6 +18,8 @@ package api
 
 import (
 	// "encoding/json"
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"strings"
@@ -78,3 +80,34 @@ func TestGetEntry(t *testing.T) {
 func TestDeleteEntry(t *testing.T) {
 
 }
+
+// TestAddFileWithManifestPath tests that adding an entry at a path which
+// already exists as a manifest just adds the entry to the manifest rather
+// than replacing the manifest with the entry
+func TestAddFileWithManifestPath(t *testing.T) {
+	// create a manifest containing "ab" and "ac"
+	manifest, _ := json.Marshal(&Manifest{
+		Entries: []ManifestEntry{
+			{Path: "ab", Hash: "ab"},
+			{Path: "ac", Hash: "ac"},
+		},
+	})
+	reader := &storage.LazyTestSectionReader{
+		SectionReader: io.NewSectionReader(bytes.NewReader(manifest), 0, int64(len(manifest))),
+	}
+	trie, err := readManifest(reader, nil, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	checkEntry(t, "ab", "ab", trie)
+	checkEntry(t, "ac", "ac", trie)
+
+	// now add path "a" and check we can still get "ab" and "ac"
+	entry := &manifestTrieEntry{}
+	entry.Path = "a"
+	entry.Hash = "a"
+	trie.addEntry(entry, nil)
+	checkEntry(t, "ab", "ab", trie)
+	checkEntry(t, "ac", "ac", trie)
+	checkEntry(t, "a", "a", trie)
+}