From 279c3c0a20e0dbee3c4b644f58e5e3b3de8e051f Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Tue, 6 Dec 2022 19:41:25 -0600
Subject: [PATCH] Fix: json values work with sql.Scanner

https://github.com/jackc/pgx/issues/1418
---
 pgtype/json.go      | 8 ++++++++
 pgtype/json_test.go | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/pgtype/json.go b/pgtype/json.go
index d0d98fc9..63338bac 100644
--- a/pgtype/json.go
+++ b/pgtype/json.go
@@ -1,6 +1,7 @@
 package pgtype
 
 import (
+	"database/sql"
 	"database/sql/driver"
 	"encoding/json"
 	"fmt"
@@ -82,6 +83,13 @@ func (JSONCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan
 		return scanPlanJSONToByteSlice{}
 	case BytesScanner:
 		return scanPlanBinaryBytesToBytesScanner{}
+
+	// Cannot rely on sql.Scanner being handled later because scanPlanJSONToJSONUnmarshal will take precedence.
+	//
+	// https://github.com/jackc/pgx/issues/1418
+	case sql.Scanner:
+		return &scanPlanSQLScanner{formatCode: format}
+
 	default:
 		return scanPlanJSONToJSONUnmarshal{}
 	}
diff --git a/pgtype/json_test.go b/pgtype/json_test.go
index db20e576..00dbbc5c 100644
--- a/pgtype/json_test.go
+++ b/pgtype/json_test.go
@@ -2,6 +2,7 @@ package pgtype_test
 
 import (
 	"context"
+	"database/sql"
 	"testing"
 
 	pgx "github.com/jackc/pgx/v5"
@@ -48,6 +49,9 @@ func TestJSONCodec(t *testing.T) {
 		{map[string]any(nil), new([]byte), isExpectedEqBytes([]byte(nil))},
 		{[]byte(nil), new([]byte), isExpectedEqBytes([]byte(nil))},
 		{nil, new([]byte), isExpectedEqBytes([]byte(nil))},
+
+		// Test sql.Scanner. (https://github.com/jackc/pgx/issues/1418)
+		{"42", new(sql.NullInt64), isExpectedEq(sql.NullInt64{Int64: 42, Valid: true})},
 	})
 
 	pgxtest.RunValueRoundTripTests(context.Background(), t, defaultConnTestRunner, pgxtest.KnownOIDQueryExecModes, "json", []pgxtest.ValueRoundTripTest{