cleanup and add test for json codec

.vscode/launch.json

@@ -1,15 +0,0 @@
-{
-    // Use IntelliSense to learn about possible attributes.
-    // Hover to view descriptions of existing attributes.
-    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
-    "version": "0.2.0",
-    "configurations": [
-        {
-            "name": "Launch Package",
-            "type": "go",
-            "request": "launch",
-            "mode": "debug",
-            "program": "${fileDirname}"
-        }
-    ]
-}

.vscode/settings.json

@@ -1,5 +0,0 @@
-{
-  "go.testEnvVars": {
-    "PGX_TEST_DATABASE":"host=127.0.0.1 user=gamerhound password=gamerhound dbname=gamerhound"
-  }
-}

pgtype/json_test.go

@@ -48,6 +48,7 @@ func TestJSONCodec(t *testing.T) {
 		Age  int    `json:"age"`
 	}
 
+	var str string
 	pgxtest.RunValueRoundTripTests(context.Background(), t, defaultConnTestRunner, nil, "json", []pgxtest.ValueRoundTripTest{
 		{nil, new(*jsonStruct), isExpectedEq((*jsonStruct)(nil))},
 		{map[string]any(nil), new(*string), isExpectedEq((*string)(nil))},
@@ -65,6 +66,14 @@ func TestJSONCodec(t *testing.T) {
 		{Issue1805(7), new(Issue1805), isExpectedEq(Issue1805(7))},
 		// Test driver.Scanner is used before json.Unmarshaler (https://github.com/jackc/pgx/issues/2146)
 		{Issue2146(7), new(*Issue2146), isPtrExpectedEq(Issue2146(7))},
+
+		// Test driver.Scanner without pointer receiver (https://github.com/jackc/pgx/issues/2204)
+		{NonPointerJSONScanner{V: stringPtr("{}")}, NonPointerJSONScanner{V: &str}, func(a any) bool {
+			if n, is := a.(NonPointerJSONScanner); is {
+				return *n.V == "{}"
+			}
+			return false
+		}},
 	})
 
 	pgxtest.RunValueRoundTripTests(context.Background(), t, defaultConnTestRunner, pgxtest.KnownOIDQueryExecModes, "json", []pgxtest.ValueRoundTripTest{
@@ -136,6 +145,27 @@ func (i Issue2146) Value() (driver.Value, error) {
 	return string(b), err
 }
 
+type NonPointerJSONScanner struct {
+	V *string
+}
+
+func (i NonPointerJSONScanner) Scan(src any) error {
+	switch c := src.(type) {
+	case string:
+		*i.V = c
+	case []byte:
+		*i.V = string(c)
+	default:
+		return errors.New("unknown source type")
+	}
+
+	return nil
+}
+
+func (i NonPointerJSONScanner) Value() (driver.Value, error) {
+	return i.V, nil
+}
+
 // https://github.com/jackc/pgx/issues/1273#issuecomment-1221414648
 func TestJSONCodecUnmarshalSQLNull(t *testing.T) {
 	defaultConnTestRunner.RunTest(context.Background(), t, func(ctx context.Context, t testing.TB, conn *pgx.Conn) {

tete/main.go

@@ -1,80 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"log"
-	"reflect"
-
-	"github.com/jackc/pgx/v5/pgxpool"
-)
-
-func main() {
-	pool, err := pgxpool.New(context.Background(), "postgres://gamerhound:gamerhound@localhost:5432/gamerhound")
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer pool.Close()
-
-	// Create the enum type.
-	_, err = pool.Exec(context.Background(), `DROP TYPE IF EXISTS test_enum_type`)
-	if err != nil {
-		log.Print(err)
-		return
-	}
-	_, err = pool.Exec(context.Background(), `CREATE TYPE test_enum_type AS ENUM ('a', 'b')`)
-	if err != nil {
-		log.Print(err)
-		return
-	}
-
-	err = testQuery(pool, "SELECT 'a'", "a")
-	if err != nil {
-		log.Printf("test TEXT error: %s\n", err)
-	}
-
-	err = testQuery(pool, "SELECT 'a'::test_enum_type", "a")
-	if err != nil {
-		log.Printf("test ENUM error: %s\n", err)
-	}
-
-	err = testQuery(pool, "SELECT '{}'::jsonb", "{}")
-	if err != nil {
-		log.Printf("test JSONB error: %s\n", err)
-	}
-}
-
-// T implements the sql.Scanner interface.
-type T struct {
-	v *any
-}
-
-func (t T) Scan(v any) error {
-	*t.v = v
-	return nil
-}
-
-// testQuery executes the query and checks if the scanned value matches
-// the expected result.
-func testQuery(pool *pgxpool.Pool, query string, expected any) error {
-	rows, err := pool.Query(context.Background(), query)
-	if err != nil {
-		return err
-	}
-	// defer rows.Close()
-
-	var got any
-	t := T{v: &got}
-	for rows.Next() {
-		if err := rows.Scan(t); err != nil {
-			return err
-		}
-	}
-	if err = rows.Err(); err != nil {
-		return err
-	}
-	if !reflect.DeepEqual(got, expected) {
-		return fmt.Errorf("expected %#v; got %#v", expected, got)
-	}
-	return nil
-}