commit storage temporarily before creating account, so host can obser…

…ve existing writes

runtime/runtime_test.go

@@ -3231,19 +3231,30 @@ func TestRuntimeTransaction_CreateAccount(t *testing.T) {
 	script := []byte(`
       transaction {
         prepare(signer: AuthAccount) {
+          // Important: Perform a write which will be pending until the end of the transaction,
+          // but should be (temporarily) committed when the AuthAccount constructor is called
+          signer.save(42, to: /storage/answer)
           AuthAccount(payer: signer)
         }
       }
     `)
 
 	var events []cadence.Event
 
+	var performedWrite bool
+
+	onWrite := func(owner, key, value []byte) {
+		performedWrite = true
+	}
+
 	runtimeInterface := &testRuntimeInterface{
-		storage: newTestLedger(nil, nil),
+		storage: newTestLedger(nil, onWrite),
 		getSigningAccounts: func() ([]Address, error) {
 			return []Address{{42}}, nil
 		},
 		createAccount: func(payer Address) (address Address, err error) {
+			// Check that pending writes were committed before
+			assert.True(t, performedWrite)
 			return Address{42}, nil
 		},
 		emitEvent: func(event cadence.Event) error {

runtime/stdlib/account.go

@@ -64,6 +64,10 @@ type AccountIDGenerator interface {
 	GenerateAccountID(address common.Address) (uint64, error)
 }
 
+type StorageCommitter interface {
+	CommitStorageTemporarily(inter *interpreter.Interpreter) error
+}
+
 type AuthAccountHandler interface {
 	AccountIDGenerator
 	BalanceProvider
@@ -77,6 +81,7 @@ type AuthAccountHandler interface {
 }
 
 type AccountCreator interface {
+	StorageCommitter
 	EventEmitter
 	AuthAccountHandler
 	// CreateAccount creates a new account.
@@ -120,6 +125,11 @@ func NewAuthAccountConstructor(creator AccountCreator) StandardLibraryValue {
 
 			payerAddress := payerAddressValue.ToAddress()
 
+			err := creator.CommitStorageTemporarily(inter)
+			if err != nil {
+				panic(err)
+			}
+
 			addressValue := interpreter.NewAddressValueFromConstructor(
 				inter,
 				func() (address common.Address) {
@@ -383,7 +393,7 @@ func newAccountAvailableBalanceGetFunction(
 }
 
 type StorageUsedProvider interface {
-	CommitStorageTemporarily(inter *interpreter.Interpreter) error
+	StorageCommitter
 	// GetStorageUsed gets storage used in bytes by the address at the moment of the function call.
 	GetStorageUsed(address common.Address) (uint64, error)
 }
@@ -422,7 +432,7 @@ func newStorageUsedGetFunction(
 }
 
 type StorageCapacityProvider interface {
-	CommitStorageTemporarily(inter *interpreter.Interpreter) error
+	StorageCommitter
 	// GetStorageCapacity gets storage capacity in bytes on the address.
 	GetStorageCapacity(address common.Address) (uint64, error)
 }