Incorporate suggestions

spanner/integration_test.go

@@ -2169,10 +2169,10 @@ func TestIntegration_BasicTypes(t *testing.T) {
 		}...)
 	}
 
-	for idx := 0; idx < 2; idx++ {
-		if idx == 1 {
-			UseNumberWithJSONDecoderEncoder()
-			defer testSetJSONProviderNumberConfig(false)
+	for _, withNumberConfigOption := range []bool{false, true} {
+		if withNumberConfigOption {
+			UseNumberWithJSONDecoderEncoder(withNumberConfigOption)
+			defer UseNumberWithJSONDecoderEncoder(!withNumberConfigOption)
 		}
 		// Write rows into table first using DML.
 		statements := make([]Statement, 0)
@@ -2224,15 +2224,15 @@ func TestIntegration_BasicTypes(t *testing.T) {
 			}
 			verifyDirectPathRemoteAddress(t)
 			want := test.wantWithDefaultConfig
-			if idx == 1 {
+			if withNumberConfigOption {
 				want = test.wantWithNumber
 			}
 			if want == nil {
 				want = test.val
 			}
 			gotp := reflect.New(reflect.TypeOf(want))
 			if err := row.Column(0, gotp.Interface()); err != nil {
-				t.Errorf("%d-%d: col:%v val:%#v, %v", idx, i, test.col, test.val, err)
+				t.Errorf("%v-%d: col:%v val:%#v, %v", withNumberConfigOption, i, test.col, test.val, err)
 				continue
 			}
 			got := reflect.Indirect(gotp).Interface()
@@ -2245,7 +2245,7 @@ func TestIntegration_BasicTypes(t *testing.T) {
 
 			// Check non-NaN cases.
 			if !testEqual(got, want) {
-				t.Errorf("%d-%d: col:%v val:%#v, got %#v, want %#v", idx, i, test.col, test.val, got, want)
+				t.Errorf("%v-%d: col:%v val:%#v, got %#v, want %#v", withNumberConfigOption, i, test.col, test.val, got, want)
 				continue
 			}
 		}
@@ -5538,12 +5538,3 @@ func checkCommonTagsGFELatency(t *testing.T, m map[tag.Key]string) {
 		t.Fatalf("Incorrect library version: %v", m[tagKeyLibVersion])
 	}
 }
-
-// helper method to enable json provider with useNumber flag, only for testing.
-func testSetJSONProviderNumberConfig(useNumber bool) {
-	jsonProvider = jsoniter.Config{
-		EscapeHTML:  true,
-		SortMapKeys: true, // Sort map keys to ensure deterministic output, to be consistent with encoding.
-		UseNumber:   useNumber,
-	}.Froze()
-}

spanner/value.go

@@ -27,7 +27,6 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
-	"sync"
 	"time"
 
 	"cloud.google.com/go/civil"
@@ -116,22 +115,20 @@ var (
 	jsonNullBytes = []byte("null")
 
 	jsonProvider = jsoniter.ConfigCompatibleWithStandardLibrary
-
-	once sync.Once
 )
 
 // UseNumberWithJSONDecoderEncoder specifies whether Cloud Spanner JSON numbers are decoded
 // as Number (preserving precision) or float64 (risking loss).
-// Defaults to float64, call this method for lossless precision.
-// NOTE: This change affects all clients created by this library, both existing and future ones.
-func UseNumberWithJSONDecoderEncoder() {
-	once.Do(func() {
-		jsonProvider = jsoniter.Config{
-			EscapeHTML:  true,
-			SortMapKeys: true, // Sort map keys to ensure deterministic output, to be consistent with encoding.
-			UseNumber:   true,
-		}.Froze()
-	})
+// Defaults to the same behavior as the standard Go library, which means decoding to float64.
+// Call this method to enable lossless precision.
+// NOTE 1: Calling this method affects the behavior of all clients created by this library, both existing and future instances.
+// NOTE 2: This method sets a global variable that is used by the client to encode/decode JSON numbers. Access to the global variable is not synchronized. You should only call this method when there are no goroutines encoding/decoding Cloud Spanner JSON values. It is recommended to only call this method during the initialization of your application, and preferably before you create any Cloud Spanner clients, and/or in tests when there are no queries being executed.
+func UseNumberWithJSONDecoderEncoder(useNumber bool) {
+	jsonProvider = jsoniter.Config{
+		EscapeHTML:  true,
+		SortMapKeys: true, // Sort map keys to ensure deterministic output, to be consistent with encoding.
+		UseNumber:   useNumber,
+	}.Froze()
 }
 
 // Encoder is the interface implemented by a custom type that can be encoded to