From df897aec9dc4228e585e8127b4db026d506d2b3c Mon Sep 17 00:00:00 2001
From: Muhammad Noor Misyuari <12197761+misyuari@users.noreply.github.com>
Date: Thu, 19 Oct 2023 14:13:09 +0700
Subject: [PATCH] fix: decode struct with pointer must be nil (#473)

---
 decode_test.go          | 7 +++++++
 internal/decoder/ptr.go | 1 +
 2 files changed, 8 insertions(+)

diff --git a/decode_test.go b/decode_test.go
index df914ed..8f32ced 100644
--- a/decode_test.go
+++ b/decode_test.go
@@ -197,6 +197,13 @@ func Test_Decoder(t *testing.T) {
 			assertEq(t, "interface{}", v.F, nil)
 			assertEq(t, "nilfunc", true, v.G == nil)
 		})
+		t.Run("struct.pointer must be nil", func(t *testing.T) {
+			var v struct {
+				A *int
+			}
+			json.Unmarshal([]byte(`{"a": "alpha"}`), &v)
+			assertEq(t, "struct.A", v.A, (*int)(nil))
+		})
 	})
 	t.Run("interface", func(t *testing.T) {
 		t.Run("number", func(t *testing.T) {
diff --git a/internal/decoder/ptr.go b/internal/decoder/ptr.go
index de12e10..ae22994 100644
--- a/internal/decoder/ptr.go
+++ b/internal/decoder/ptr.go
@@ -85,6 +85,7 @@ func (d *ptrDecoder) Decode(ctx *RuntimeContext, cursor, depth int64, p unsafe.P
 	}
 	c, err := d.dec.Decode(ctx, cursor, depth, newptr)
 	if err != nil {
+		*(*unsafe.Pointer)(p) = nil
 		return 0, err
 	}
 	cursor = c