From 4d0d8261cce2fc495c48bd8c8a45faf79de4f526 Mon Sep 17 00:00:00 2001
From: Michael Montgomery <mmontg1@gmail.com>
Date: Tue, 15 Dec 2020 14:17:00 -0600
Subject: [PATCH] Ensure uninitialized map is initialized when unmarshaling
 json Add tests for this scenario

---
 slices/map.go      |  3 +++
 slices/map_test.go | 11 +++++++++++
 2 files changed, 14 insertions(+)

diff --git a/slices/map.go b/slices/map.go
index d7f58ed4..c99e8a13 100644
--- a/slices/map.go
+++ b/slices/map.go
@@ -51,6 +51,9 @@ func (m Map) UnmarshalJSON(b []byte) error {
 	if err != nil {
 		return err
 	}
+	if m == nil {
+		m = Map{}
+	}
 	for key, value := range stuff {
 		m[key] = value
 	}
diff --git a/slices/map_test.go b/slices/map_test.go
index e5d4963b..265d9940 100644
--- a/slices/map_test.go
+++ b/slices/map_test.go
@@ -24,3 +24,14 @@ func Test_Map_MarshalJSON(t *testing.T) {
 	r.NoError(err)
 	r.Equal([]byte(`{"a":"b"}`), b)
 }
+
+func Test_Map_UnMarshalJSON_uninitialized_map_does_not_panic(t *testing.T) {
+	r := require.New(t)
+
+	maps := make([]Map, 0)
+	r.NotPanics(func() {
+		err := json.Unmarshal([]byte(`[{"a": "b"}]`), &maps)
+		r.NoError(err)
+		r.Len(maps, 1)
+	})
+}