From 39143f46f8064c03ccbfdb8588da88964dc64d5c Mon Sep 17 00:00:00 2001
From: James Nugent <james@jen20.com>
Date: Mon, 20 Jun 2016 19:53:10 +0300
Subject: [PATCH] Fix bug with unquoting null from JSON-encoded HCL

Fixes hashicorp/terraform#6774.
---
 decoder_test.go                 | 13 +++++++++++++
 hcl/token/token.go              |  5 +++++
 test-fixtures/null_strings.json |  7 +++++++
 3 files changed, 25 insertions(+)
 create mode 100644 test-fixtures/null_strings.json

diff --git a/decoder_test.go b/decoder_test.go
index 79994cb..b441496 100644
--- a/decoder_test.go
+++ b/decoder_test.go
@@ -109,6 +109,19 @@ func TestDecode_interface(t *testing.T) {
 			false,
 			map[string]interface{}{"foo": "bar\nbaz"},
 		},
+		{
+			"null_strings.json",
+			false,
+			map[string]interface{}{
+				"module": []map[string]interface{}{
+					map[string]interface{}{
+						"app": []map[string]interface{}{
+							map[string]interface{}{"foo": ""},
+						},
+					},
+				},
+			},
+		},
 		{
 			"scientific.json",
 			false,
diff --git a/hcl/token/token.go b/hcl/token/token.go
index 6e99498..e37c066 100644
--- a/hcl/token/token.go
+++ b/hcl/token/token.go
@@ -152,6 +152,11 @@ func (t Token) Value() interface{} {
 			f = strconv.Unquote
 		}
 
+		// This case occurs if json null is used
+		if t.Text == "" {
+			return ""
+		}
+
 		v, err := f(t.Text)
 		if err != nil {
 			panic(fmt.Sprintf("unquote %s err: %s", t.Text, err))
diff --git a/test-fixtures/null_strings.json b/test-fixtures/null_strings.json
new file mode 100644
index 0000000..a5b8a5a
--- /dev/null
+++ b/test-fixtures/null_strings.json
@@ -0,0 +1,7 @@
+{
+  "module": {
+    "app": {
+      "foo": null
+    }
+  }
+}