fix(golang): correctly map nullable PostgreSQL UUID[] columns

go.mod

@@ -0,0 +1,3 @@
+module github.com/sqlc-dev/sqlc
+
+go 1.22.2

internal/codegen/golang/types.go

@@ -0,0 +1,80 @@
+package golang
+
+// SQLPackage identifies the database driver/package target.
+type SQLPackage string
+
+const (
+	SQLPackageStandard SQLPackage = "database/sql"
+	SQLPackagePGXV4    SQLPackage = "pgx/v4"
+	SQLPackagePGXV5    SQLPackage = "pgx/v5"
+)
+
+// Settings represents golang generator configuration.
+type Settings struct {
+	SQLPackage    SQLPackage
+	GoTypePointer bool
+}
+
+// Column represents a database column for code generation.
+type Column struct {
+	Name    string
+	Type    string
+	NotNull bool
+	IsArray bool
+}
+
+// Generator manages Go code generation.
+type Generator struct{}
+
+func (g *Generator) dbType(col *Column) string {
+	switch col.Type {
+	case "uuid", "uuid[]":
+		return "uuid.UUID"
+	case "text", "varchar":
+		return "string"
+	case "integer", "int":
+		return "int32"
+	case "bigint":
+		return "int64"
+	case "boolean", "bool":
+		return "bool"
+	default:
+		return "interface{}"
+	}
+}
+
+// GoType maps a database column and its nullability/array status to the appropriate Go type representation.
+func (g *Generator) GoType(col *Column, settings Settings) string {
+	base := g.dbType(col)
+	if col.IsArray {
+		sliceTyp := "[]" + base
+		if !col.NotNull {
+			// For standard database/sql and drivers needing pointer indirection on nullable slices
+			if settings.SQLPackage == SQLPackageStandard || settings.GoTypePointer {
+				return "*" + sliceTyp
+			}
+			return sliceTyp
+		}
+		return sliceTyp
+	}
+
+	if !col.NotNull {
+		if settings.GoTypePointer {
+			return "*" + base
+		}
+		switch base {
+		case "string":
+			return "sql.NullString"
+		case "int32":
+			return "sql.NullInt32"
+		case "int64":
+			return "sql.NullInt64"
+		case "bool":
+			return "sql.NullBool"
+		default:
+			return "*" + base
+		}
+	}
+
+	return base
+}

internal/codegen/golang/types_test.go

@@ -0,0 +1,68 @@
+package golang
+
+import "testing"
+
+func TestGoType_NullableUUIDArray(t *testing.T) {
+	g := &Generator{}
+
+	tests := []struct {
+		name     string
+		col      *Column
+		settings Settings
+		expected string
+	}{
+		{
+			name: "non-nullable uuid array (lib/pq)",
+			col: &Column{
+				Name:    "associated_ids",
+				Type:    "uuid[]",
+				NotNull: true,
+				IsArray: true,
+			},
+			settings: Settings{SQLPackage: SQLPackageStandard},
+			expected: "[]uuid.UUID",
+		},
+		{
+			name: "nullable uuid array (lib/pq standard driver)",
+			col: &Column{
+				Name:    "associated_ids",
+				Type:    "uuid[]",
+				NotNull: false,
+				IsArray: true,
+			},
+			settings: Settings{SQLPackage: SQLPackageStandard},
+			expected: "*[]uuid.UUID",
+		},
+		{
+			name: "nullable uuid array with pointer setting enabled",
+			col: &Column{
+				Name:    "associated_ids",
+				Type:    "uuid[]",
+				NotNull: false,
+				IsArray: true,
+			},
+			settings: Settings{SQLPackage: SQLPackagePGXV5, GoTypePointer: true},
+			expected: "*[]uuid.UUID",
+		},
+		{
+			name: "nullable uuid array with native pgx/v5 driver",
+			col: &Column{
+				Name:    "associated_ids",
+				Type:    "uuid[]",
+				NotNull: false,
+				IsArray: true,
+			},
+			settings: Settings{SQLPackage: SQLPackagePGXV5, GoTypePointer: false},
+			expected: "[]uuid.UUID",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			actual := g.GoType(tt.col, tt.settings)
+			if actual != tt.expected {
+				t.Errorf("GoType() = %v, expected %v", actual, tt.expected)
+			}
+		})
+	}
+}