From b708c8b985ce0602ab017cab5f03a6ae7fd2f2be Mon Sep 17 00:00:00 2001
From: leighhopcroft <leighhopcroft@googlemail.com>
Date: Tue, 2 Jun 2020 19:07:10 +0100
Subject: [PATCH] support NaN in Numeric.AssignTo

---
 numeric.go      |  7 +++++++
 numeric_test.go | 18 ++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/numeric.go b/numeric.go
index f4ddb789..644ee23f 100644
--- a/numeric.go
+++ b/numeric.go
@@ -267,6 +267,13 @@ func (src *Numeric) AssignTo(dst interface{}) error {
 		}
 	case Null:
 		return NullAssignTo(dst)
+	case Undefined:
+		switch v := dst.(type) {
+		case *float32:
+			*v = float32(math.NaN())
+		case *float64:
+			*v = math.NaN()
+		}
 	}
 
 	return nil
diff --git a/numeric_test.go b/numeric_test.go
index 3b099b55..ee72ff5e 100644
--- a/numeric_test.go
+++ b/numeric_test.go
@@ -269,6 +269,8 @@ func TestNumericAssignTo(t *testing.T) {
 		{src: &pgtype.Numeric{Int: big.NewInt(0), Status: pgtype.Null}, dst: &pi8, expected: ((*int8)(nil))},
 		{src: &pgtype.Numeric{Int: big.NewInt(0), Status: pgtype.Null}, dst: &_pi8, expected: ((*_int8)(nil))},
 		{src: &pgtype.Numeric{Int: big.NewInt(1006), Exp: -2, Status: pgtype.Present}, dst: &f64, expected: float64(10.06)}, // https://github.com/jackc/pgtype/issues/27
+		{src: &pgtype.Numeric{}, dst: &f64, expected: math.NaN()},
+		{src: &pgtype.Numeric{}, dst: &f32, expected: float32(math.NaN())},
 	}
 
 	for i, tt := range simpleTests {
@@ -277,8 +279,20 @@ func TestNumericAssignTo(t *testing.T) {
 			t.Errorf("%d: %v", i, err)
 		}
 
-		if dst := reflect.ValueOf(tt.dst).Elem().Interface(); dst != tt.expected {
-			t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+		dst := reflect.ValueOf(tt.dst).Elem().Interface()
+		switch dstTyped := dst.(type) {
+		case float32:
+			if math.IsNaN(float64(tt.expected.(float32))) && !math.IsNaN(float64(dstTyped)) {
+				t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+			}
+		case float64:
+			if math.IsNaN(tt.expected.(float64)) && !math.IsNaN(dstTyped) {
+				t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+			}
+		default:
+			if dst != tt.expected {
+				t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+			}
 		}
 	}