[#787] util/attributes: Reuse attribute struct to update parents list

Parser should reuse existing attributes from the cache to update list
of the parent links in it. Parent links should be unique.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/util/attributes/parser.go

@@ -48,7 +48,8 @@ func ParseV2Attributes(attrs []string, excl []string) ([]*netmap.NodeAttribute,
 			key := pair[0]
 			value := pair[1]
 
-			if at, ok := cache[key]; ok && at.Value() != value {
+			attribute, present := cache[key]
+			if present && attribute.Value() != value {
 				return nil, errNonUniqueBucket
 			}
 
@@ -56,20 +57,26 @@ func ParseV2Attributes(attrs []string, excl []string) ([]*netmap.NodeAttribute,
 				return nil, errUnexpectedKey
 			}
 
-			// replace non-printable symbols with escaped symbols without escape character
-			key = replaceEscaping(key, true)
-			value = replaceEscaping(value, true)
+			if !present {
+				// replace non-printable symbols with escaped symbols without escape character
+				key = replaceEscaping(key, true)
+				value = replaceEscaping(value, true)
 
-			attribute := netmap.NewNodeAttribute()
-			attribute.SetKey(key)
-			attribute.SetValue(value)
+				attribute = netmap.NewNodeAttribute()
+				attribute.SetKey(key)
+				attribute.SetValue(value)
+
+				cache[key] = attribute
+			}
 
 			if parentKey != "" {
-				attribute.SetParentKeys(parentKey)
+				parentKeys := attribute.ParentKeys()
+				if !hasString(parentKeys, parentKey) {
+					attribute.SetParentKeys(append(parentKeys, parentKey)...)
+				}
 			}
 
 			parentKey = key
-			cache[key] = attribute
 		}
 	}
 
@@ -106,3 +113,12 @@ func replaceEscaping(target string, rollback bool) (s string) {
 
 	return
 }
+
+func hasString(lst []string, v string) bool {
+	for i := range lst {
+		if lst[i] == v {
+			return true
+		}
+	}
+	return false
+}

pkg/util/attributes/parser_test.go

@@ -25,7 +25,6 @@ func TestParseV2Attributes(t *testing.T) {
 		bad := append(good, "StorageType:SSD/Cell:QLC")
 		_, err = attributes.ParseV2Attributes(bad, nil)
 		require.Error(t, err)
-
 	})
 
 	t.Run("malformed", func(t *testing.T) {
@@ -69,4 +68,30 @@ func TestParseV2Attributes(t *testing.T) {
 		require.Equal(t, attrs[1].Key(), `Ke/y2`)
 		require.Equal(t, attrs[1].Value(), `Va:lue`)
 	})
+
+	t.Run("same attributes", func(t *testing.T) {
+		from := []string{"/a:b", "/a:b"}
+		attrs, err := attributes.ParseV2Attributes(from, nil)
+		require.NoError(t, err)
+		require.Len(t, attrs, 1)
+	})
+
+	t.Run("multiple parents", func(t *testing.T) {
+		from := []string{
+			"/parent1:x/child:x",
+			"/parent2:x/child:x",
+			"/parent2:x/child:x/subchild:x",
+		}
+		attrs, err := attributes.ParseV2Attributes(from, nil)
+		require.NoError(t, err)
+
+		var flag bool
+		for _, attr := range attrs {
+			if attr.Key() == "child" {
+				flag = true
+				require.Equal(t, attr.ParentKeys(), []string{"parent1", "parent2"})
+			}
+		}
+		require.True(t, flag)
+	})
 }