feat(spanner): allow untyped nil values in parameterized queries

spanner/integration_test.go

@@ -1715,9 +1715,63 @@ func TestIntegration_BasicTypes(t *testing.T) {
 		{col: "NumericArray", val: []NullNumeric(nil)},
 		{col: "NumericArray", val: []NullNumeric{}},
 		{col: "NumericArray", val: []NullNumeric{{n1, true}, {n2, true}, {}}},
+		{col: "String", val: nil, want: NullString{}},
+		{col: "StringArray", val: nil, want: []NullString(nil)},
+		{col: "Bytes", val: nil, want: []byte(nil)},
+		{col: "BytesArray", val: nil, want: [][]byte(nil)},
+		{col: "Int64a", val: nil, want: NullInt64{}},
+		{col: "Int64Array", val: nil, want: []NullInt64(nil)},
+		{col: "Bool", val: nil, want: NullBool{}},
+		{col: "BoolArray", val: nil, want: []NullBool(nil)},
+		{col: "Float64", val: nil, want: NullFloat64{}},
+		{col: "Float64Array", val: nil, want: []NullFloat64(nil)},
+		{col: "Date", val: nil, want: NullDate{}},
+		{col: "DateArray", val: nil, want: []NullDate(nil)},
+		{col: "Timestamp", val: nil, want: NullTime{}},
+		{col: "TimestampArray", val: nil, want: []NullTime(nil)},
+		{col: "Numeric", val: nil, want: NullNumeric{}},
+		{col: "NumericArray", val: nil, want: []NullNumeric(nil)},
+	}
+
+	// Write rows into table first using DML. Only do this on real Spanner
+	// as the emulator does not support untyped parameters.
+	// TODO: Remove when the emulator supports untyped parameters.
+	if isEmulatorEnvSet() {
+		statements := make([]Statement, 0)
+		for i, test := range tests {
+			stmt := NewStatement(fmt.Sprintf("INSERT INTO Types (RowId, `%s`) VALUES (@id, @value)", test.col))
+			// Note: We are not setting the parameter type here to ensure that it
+			// can be automatically recognized when it is actually needed.
+			stmt.Params["id"] = i
+			stmt.Params["value"] = test.val
+			statements = append(statements, stmt)
+		}
+		_, err := client.ReadWriteTransaction(ctx, func(ctx context.Context, tx *ReadWriteTransaction) error {
+			rowCounts, err := tx.BatchUpdate(ctx, statements)
+			if err != nil {
+				return err
+			}
+			if len(rowCounts) != len(tests) {
+				return fmt.Errorf("rowCounts length mismatch\nGot: %v\nWant: %v", len(rowCounts), len(tests))
+			}
+			for i, c := range rowCounts {
+				if c != 1 {
+					return fmt.Errorf("row count mismatch for row %v:\nGot: %v\nWant: %v", i, c, 1)
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			t.Fatalf("failed to insert values using DML: %v", err)
+		}
+		// Delete all the rows so we can insert them using mutations as well.
+		_, err = client.Apply(ctx, []*Mutation{Delete("Types", AllKeys())})
+		if err != nil {
+			t.Fatalf("failed to delete all rows: %v", err)
+		}
 	}
 
-	// Write rows into table first.
+	// Verify that we can insert the rows using mutations.
 	var muts []*Mutation
 	for i, test := range tests {
 		muts = append(muts, InsertOrUpdate("Types", []string{"RowID", test.col}, []interface{}{i, test.val}))

spanner/statement.go

@@ -17,7 +17,6 @@ limitations under the License.
 package spanner
 
 import (
-	"errors"
 	"fmt"
 
 	proto3 "github.com/golang/protobuf/ptypes/struct"
@@ -48,11 +47,6 @@ func NewStatement(sql string) Statement {
 	return Statement{SQL: sql, Params: map[string]interface{}{}}
 }
 
-var (
-	errNilParam = errors.New("use T(nil), not nil")
-	errNoType   = errors.New("no type information")
-)
-
 // convertParams converts a statement's parameters into proto Param and
 // ParamTypes.
 func (s *Statement) convertParams() (*structpb.Struct, map[string]*sppb.Type, error) {
@@ -61,18 +55,14 @@ func (s *Statement) convertParams() (*structpb.Struct, map[string]*sppb.Type, er
 	}
 	paramTypes := map[string]*sppb.Type{}
 	for k, v := range s.Params {
-		if v == nil {
-			return nil, nil, errBindParam(k, v, errNilParam)
-		}
 		val, t, err := encodeValue(v)
 		if err != nil {
 			return nil, nil, errBindParam(k, v, err)
 		}
-		if t == nil { // should not happen, because of nil check above
-			return nil, nil, errBindParam(k, v, errNoType)
-		}
 		params.Fields[k] = val
-		paramTypes[k] = t
+		if t != nil {
+			paramTypes[k] = t
+		}
 	}
 
 	return params, paramTypes, nil

spanner/statement_test.go

@@ -159,6 +159,12 @@ func TestConvertParams(t *testing.T) {
 			listProto(listProto(intProto(10)), listProto(intProto(20))),
 			listType(structType(mkField("field", intType()))),
 		},
+		// Untyped null
+		{
+			nil,
+			nullProto(),
+			nil,
+		},
 	} {
 		st.Params["var"] = test.val
 		gotParams, gotParamTypes, gotErr := st.convertParams()
@@ -179,23 +185,6 @@ func TestConvertParams(t *testing.T) {
 			t.Errorf("%#v: got %v, want %v\n", test.val, gotParamType, test.wantField)
 		}
 	}
-
-	// Verify type error reporting.
-	for _, test := range []struct {
-		val     interface{}
-		wantErr error
-	}{
-		{
-			nil,
-			errBindParam("var", nil, errNilParam),
-		},
-	} {
-		st.Params["var"] = test.val
-		_, _, gotErr := st.convertParams()
-		if !testEqual(gotErr, test.wantErr) {
-			t.Errorf("value %#v:\ngot:  %v\nwant: %v", test.val, gotErr, test.wantErr)
-		}
-	}
 }
 
 func TestNewStatement(t *testing.T) {