Merge pull request #422 from hashicorp/alisdair/hclwrite-empty-labels

hclwrite: Allow blank quoted string block labels

hclwrite/ast_block.go

@@ -159,6 +159,12 @@ func (bl *blockLabels) Current() []string {
 				if !diags.HasErrors() {
 					labelNames = append(labelNames, labelString)
 				}
+			} else if len(tokens) == 2 &&
+				tokens[0].Type == hclsyntax.TokenOQuote &&
+				tokens[1].Type == hclsyntax.TokenCQuote {
+				// An open quote followed immediately by a closing quote is a
+				// valid but unusual blank string label.
+				labelNames = append(labelNames, "")
 			}
 
 		default:

hclwrite/ast_block_test.go

@@ -107,6 +107,13 @@ escape "\u0041" {
 `,
 			[]string{"\u0041"},
 		},
+		{
+			`
+blank "" {
+}
+`,
+			[]string{""},
+		},
 	}
 
 	for _, test := range tests {
@@ -414,7 +421,7 @@ func TestBlockSetLabels(t *testing.T) {
 		{
 			`foo "hoge" /* foo */  "" {}`,
 			"foo",
-			[]string{"hoge"},
+			[]string{"hoge", ""},
 			[]string{"fuga"}, // force quoted form even if the old one is unquoted.
 			Tokens{
 				{