Use verify_token=null as verified to avoid unique constraint

We were using verify_token="" to mean that the user was verified. We need a unique constraint on verify_token to prevent two users from getting the same verify link in their email. This means that if we have two verified users, they will both have verify_token="", which triggers the unique constraint. Oops. However, null is an exception to unique constraints, so we're now using that instead to mean verified.

server/account.go

@@ -54,7 +54,7 @@ func (s *Server) register(w http.ResponseWriter, req *http.Request) {
 
 	var registerResponse RegisterResponse
 
-	var token auth.VerifyTokenString
+	var token *auth.VerifyTokenString
 
 modes:
 	switch verificationMode {
@@ -78,7 +78,8 @@ modes:
 	case env.AccountVerificationModeEmailVerify:
 		// Not verified until they click their email link.
 		registerResponse.Verified = false
-		token, err = s.auth.NewVerifyTokenString()
+		newToken, err := s.auth.NewVerifyTokenString()
+		token = &newToken
 
 		if err != nil {
 			internalServiceErrorJson(w, err, "Error generating verify token string")
@@ -102,8 +103,8 @@ modes:
 		return
 	}
 
-	if len(token) > 0 {
+	if token != nil {
-		err = s.mail.SendVerificationEmail(registerRequest.Email, token)
+		err = s.mail.SendVerificationEmail(registerRequest.Email, *token)
 	}
 
 	if err != nil {

server/account_test.go

@@ -243,7 +243,7 @@ func TestServerRegisterAccountVerification(t *testing.T) {
 				if testStore.Called.CreateAccount == nil {
 					t.Fatalf("Expected CreateAccount to be called")
 				}
-				tokenPassedIn := testStore.Called.CreateAccount.VerifyToken != ""
+				tokenPassedIn := testStore.Called.CreateAccount.VerifyToken != nil
 				if tc.expectedVerified && tokenPassedIn {
 					t.Errorf("Expected new account to be verified, thus expected verifyToken *not to be passed in* to call to CreateAccount.")
 				}

server/server_test.go

@@ -90,7 +90,7 @@ type CreateAccountCall struct {
 	Email          auth.Email
 	Password       auth.Password
 	ClientSaltSeed auth.ClientSaltSeed
-	VerifyToken    auth.VerifyTokenString
+	VerifyToken    *auth.VerifyTokenString
 }
 
 // Whether functions are called, and sometimes what they're called with
@@ -154,7 +154,7 @@ func (s *TestStore) GetUserId(auth.Email, auth.Password) (auth.UserId, error) {
 	return 0, s.Errors.GetUserId
 }
 
-func (s *TestStore) CreateAccount(email auth.Email, password auth.Password, seed auth.ClientSaltSeed, verifyToken auth.VerifyTokenString) error {
+func (s *TestStore) CreateAccount(email auth.Email, password auth.Password, seed auth.ClientSaltSeed, verifyToken *auth.VerifyTokenString) error {
 	s.Called.CreateAccount = &CreateAccountCall{
 		Email:          email,
 		Password:       password,

store/account_test.go

@@ -18,14 +18,14 @@ func expectAccountMatch(
 	expectedEmail auth.Email,
 	password auth.Password,
 	seed auth.ClientSaltSeed,
-	expectedVerifyTokenString auth.VerifyTokenString,
+	expectedVerifyTokenString *auth.VerifyTokenString,
 	approxVerifyExpiration *time.Time,
 ) {
 	var key auth.KDFKey
 	var salt auth.ServerSalt
 	var email auth.Email
 	var verifyExpiration *time.Time
-	var verifyTokenString auth.VerifyTokenString
+	var verifyTokenString *auth.VerifyTokenString
 
 	err := s.db.QueryRow(
 		`SELECT key, server_salt, email, verify_token, verify_expiration from accounts WHERE normalized_email=? AND client_salt_seed=?`,
@@ -47,13 +47,23 @@ func expectAccountMatch(
 		t.Fatalf("Email case not as expected. Want: %s Got: %s", email, expectedEmail)
 	}
 
-	if verifyTokenString != expectedVerifyTokenString {
+	if (verifyTokenString == nil) != (expectedVerifyTokenString == nil) {
+		t.Fatalf(
+			"Verify token string nil-ness not as expected. Want: %v Got: %v",
+			expectedVerifyTokenString == nil,
+			verifyTokenString == nil,
+		)
+	}
+
+	if expectedVerifyTokenString != nil {
+		if *verifyTokenString != *expectedVerifyTokenString {
 			t.Fatalf(
 				"Verify token string not as expected. Want: %s Got: %s",
-			expectedVerifyTokenString,
+				*expectedVerifyTokenString,
-			verifyTokenString,
+				*verifyTokenString,
 			)
 		}
+	}
 
 	if approxVerifyExpiration != nil {
 		if verifyExpiration == nil {
@@ -104,18 +114,18 @@ func TestStoreCreateAccount(t *testing.T) {
 
 	// Create an account. Make it verified (i.e. no token) for the usual
 	// case. We'll test unverified (with token) separately.
-	if err := s.CreateAccount(email, password, seed, ""); err != nil {
+	if err := s.CreateAccount(email, password, seed, nil); err != nil {
 		t.Fatalf("Unexpected error in CreateAccount: %+v", err)
 	}
 
 	// Get and confirm the account we just put in
-	expectAccountMatch(t, &s, normEmail, email, password, seed, "", nil)
+	expectAccountMatch(t, &s, normEmail, email, password, seed, nil, nil)
 
 	newPassword := auth.Password("xyz")
 
 	// Try to create a new account with the same email and different password,
 	// fail because email already exists
-	if err := s.CreateAccount(email, newPassword, seed, ""); err != ErrDuplicateAccount {
+	if err := s.CreateAccount(email, newPassword, seed, nil); err != ErrDuplicateAccount {
 		t.Fatalf(`CreateAccount err: wanted "%+v", got "%+v"`, ErrDuplicateAccount, err)
 	}
 
@@ -123,43 +133,79 @@ func TestStoreCreateAccount(t *testing.T) {
 
 	// Try to create a new account with the same email different capitalization.
 	// fail because email already exists
-	if err := s.CreateAccount(differentCaseEmail, password, seed, ""); err != ErrDuplicateAccount {
+	if err := s.CreateAccount(differentCaseEmail, password, seed, nil); err != ErrDuplicateAccount {
 		t.Fatalf(`CreateAccount err (for case insensitivity check): wanted "%+v", got "%+v"`, ErrDuplicateAccount, err)
 	}
 
 	// Get the email and same *first* password we successfully put in
-	expectAccountMatch(t, &s, normEmail, email, password, seed, "", nil)
+	expectAccountMatch(t, &s, normEmail, email, password, seed, nil, nil)
 }
 
-// Test that I can call CreateAccount twice
+// Test that I can use CreateAccount twice for different emails with no veriy token
-// Try CreateAccount twice with different emails and different password, succeed both times
+// This is related to https://github.com/lbryio/wallet-sync-server/issues/13
-// This is in response to https://github.com/lbryio/wallet-sync-server/issues/13
+func TestStoreCreateAccountTwoVerifiedSucceed(t *testing.T) {
-func TestStoreCreateTwoAccounts(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	email, normEmail := auth.Email("Abc@Example.Com"), auth.NormalizedEmail("abc@example.com")
+	email1, normEmail1 := auth.Email("Abc@Example.Com"), auth.NormalizedEmail("abc@example.com")
-	password, seed := auth.Password("123"), auth.ClientSaltSeed("abcd1234abcd1234")
+	password1, seed1 := auth.Password("123"), auth.ClientSaltSeed("abcd1234abcd1234")
 
-	// Create an account. Make it verified (i.e. no token) for the usual
+	email2, normEmail2 := auth.Email("Abc2@Example.Com"), auth.NormalizedEmail("abc2@example.com")
+	password2, seed2 := auth.Password("123"), auth.ClientSaltSeed("abcd1234abcd1234")
+
+	// Create a couple accounts. Don't care if they have the same password.
+	// Make them verified (i.e. no token) for the usual
 	// case. We'll test unverified (with token) separately.
-	if err := s.CreateAccount(email, password, seed, ""); err != nil {
+	if err := s.CreateAccount(email1, password1, seed1, nil); err != nil {
 		t.Fatalf("Unexpected error in CreateAccount: %+v", err)
 	}
 
-	email, normEmail = auth.Email("Abc2@Example.Com"), auth.NormalizedEmail("abc2@example.com")
+	if err := s.CreateAccount(email2, password2, seed2, nil); err != nil {
-	password, seed = auth.Password("123"), auth.ClientSaltSeed("abcd1234abcd1234")
-
-	// Create another account. Don't care if it has the same password as the first one.
-	// Make it verified (i.e. no token) for the usual
-	// case. We'll test unverified (with token) separately.
-	if err := s.CreateAccount(email, password, seed, ""); err != nil {
 		t.Fatalf("Unexpected error in CreateAccount: %+v", err)
 	}
 
-	// Get and confirm the account we just put in
+	// Get and confirm the accounts we just put in
-	expectAccountMatch(t, &s, normEmail, email, password, seed, "", nil)
+	expectAccountMatch(t, &s, normEmail1, email1, password1, seed1, nil, nil)
+	expectAccountMatch(t, &s, normEmail2, email2, password2, seed2, nil, nil)
+}
 
+// Test that I cannot use CreateAccount twice with the same verify token, but
+//   I can with different verify tokens
+// This is related to https://github.com/lbryio/wallet-sync-server/issues/13
+func TestStoreCreateAccountTwoSameVerfiyTokenFail(t *testing.T) {
+	s, sqliteTmpFile := StoreTestInit(t)
+	defer StoreTestCleanup(sqliteTmpFile)
+
+	email1, normEmail1 := auth.Email("Abc@Example.Com"), auth.NormalizedEmail("abc@example.com")
+	password1, seed1 := auth.Password("123"), auth.ClientSaltSeed("abcd1234abcd1234")
+	verifyToken1 := auth.VerifyTokenString("abcd1234abcd1234abcd1234abcd1234")
+
+	email2, normEmail2 := auth.Email("Abc2@Example.Com"), auth.NormalizedEmail("abc2@example.com")
+	password2, seed2 := auth.Password("xyz"), auth.ClientSaltSeed("abcd1234abcd1234")
+	verifyToken2 := auth.VerifyTokenString("00001234abcd1234abcd123400000000")
+
+	// Create the first account
+	if err := s.CreateAccount(email1, password1, seed1, &verifyToken1); err != nil {
+		t.Fatalf("Unexpected error in CreateAccount: %+v", err)
+	}
+
+	// Try to create the second account with the same verify token, fail
+	if err := s.CreateAccount(email2, password2, seed2, &verifyToken1); err != ErrDuplicateAccount {
+		t.Fatalf(`CreateAccount err: wanted "%+v", got "%+v"`, ErrDuplicateAccount, err)
+	}
+
+	// Confirm that it didn't save
+	expectAccountNotExists(t, &s, normEmail2)
+
+	// Create the second account with a different verify token
+	if err := s.CreateAccount(email2, password2, seed2, &verifyToken2); err != nil {
+		t.Fatalf("Unexpected error in CreateAccount: %+v", err)
+	}
+
+	// Get and confirm the accounts we just put in
+	approxVerifyExpiration := time.Now().Add(time.Hour * 24 * 2).UTC()
+	expectAccountMatch(t, &s, normEmail1, email1, password1, seed1, &verifyToken1, &approxVerifyExpiration)
+	expectAccountMatch(t, &s, normEmail2, email2, password2, seed2, &verifyToken2, &approxVerifyExpiration)
 }
 
 // Try CreateAccount with a verification string, thus unverified
@@ -171,13 +217,14 @@ func TestStoreCreateAccountUnverified(t *testing.T) {
 	password, seed := auth.Password("123"), auth.ClientSaltSeed("abcd1234abcd1234")
 
 	// Create an account
-	if err := s.CreateAccount(email, password, seed, "abcd1234abcd1234abcd1234abcd1234"); err != nil {
+	verifyToken := auth.VerifyTokenString("abcd1234abcd1234abcd1234abcd1234")
+	if err := s.CreateAccount(email, password, seed, &verifyToken); err != nil {
 		t.Fatalf("Unexpected error in CreateAccount: %+v", err)
 	}
 
 	// Get and confirm the account we just put in
 	approxVerifyExpiration := time.Now().Add(time.Hour * 24 * 2).UTC()
-	expectAccountMatch(t, &s, normEmail, email, password, seed, "abcd1234abcd1234abcd1234abcd1234", &approxVerifyExpiration)
+	expectAccountMatch(t, &s, normEmail, email, password, seed, &verifyToken, &approxVerifyExpiration)
 }
 
 // Test GetUserId for nonexisting email
@@ -197,7 +244,7 @@ func TestStoreGetUserIdAccountExists(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	createdUserId, email, password, _ := makeTestUser(t, &s, "", nil)
+	createdUserId, email, password, _ := makeTestUser(t, &s, nil, nil)
 
 	// Check that the userId is correct for the email, irrespective of the case of
 	// the characters in the email.
@@ -225,7 +272,8 @@ func TestStoreGetUserIdAccountUnverified(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	_, email, password, _ := makeTestUser(t, &s, "abcd1234abcd1234abcd1234abcd1234", &time.Time{})
+	verifyToken := auth.VerifyTokenString("abcd1234abcd1234abcd1234abcd1234")
+	_, email, password, _ := makeTestUser(t, &s, &verifyToken, &time.Time{})
 
 	// Check that it won't return if the account is unverified
 	if userId, err := s.GetUserId(email, password); err != ErrNotVerified || userId != 0 {
@@ -264,7 +312,7 @@ func TestStoreAccountEmptyFields(t *testing.T) {
 
 			var sqliteErr sqlite3.Error
 
-			err := s.CreateAccount(tc.email, tc.password, tc.clientSaltSeed, "")
+			err := s.CreateAccount(tc.email, tc.password, tc.clientSaltSeed, nil)
 			if errors.As(err, &sqliteErr) {
 				if errors.Is(sqliteErr.ExtendedCode, sqlite3.ErrConstraintCheck) {
 					return // We got the error we expected
@@ -280,7 +328,7 @@ func TestStoreGetClientSaltSeedAccountExists(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	_, email, _, createdSeed := makeTestUser(t, &s, "", nil)
+	_, email, _, createdSeed := makeTestUser(t, &s, nil, nil)
 
 	// Check that the seed is correct for the email, irrespective of the case of
 	// the characters in the email.
@@ -315,7 +363,7 @@ func TestUpdateVerifyTokenStringSuccess(t *testing.T) {
 	verifyTokenString1 := auth.VerifyTokenString("00000000000000000000000000000000")
 	time1 := time.Time{}
 
-	_, email, password, createdSeed := makeTestUser(t, &s, verifyTokenString1, &time1)
+	_, email, password, createdSeed := makeTestUser(t, &s, &verifyTokenString1, &time1)
 
 	// we're not testing normalization features so we'll just use this here
 	normEmail := email.Normalize()
@@ -332,12 +380,12 @@ func TestUpdateVerifyTokenStringSuccess(t *testing.T) {
 	if err := s.UpdateVerifyTokenString(lowerEmail, verifyTokenString2); err != nil {
 		t.Fatalf("Unexpected error in UpdateVerifyTokenString: err: %+v", err)
 	}
-	expectAccountMatch(t, &s, normEmail, email, password, createdSeed, verifyTokenString2, &approxVerifyExpiration)
+	expectAccountMatch(t, &s, normEmail, email, password, createdSeed, &verifyTokenString2, &approxVerifyExpiration)
 
 	if err := s.UpdateVerifyTokenString(upperEmail, verifyTokenString3); err != nil {
 		t.Fatalf("Unexpected error in UpdateVerifyTokenString: err: %+v", err)
 	}
-	expectAccountMatch(t, &s, normEmail, email, password, createdSeed, verifyTokenString3, &approxVerifyExpiration)
+	expectAccountMatch(t, &s, normEmail, email, password, createdSeed, &verifyTokenString3, &approxVerifyExpiration)
 }
 
 // Test UpdateVerifyTokenString for nonexisting email
@@ -357,7 +405,7 @@ func TestStoreUpdateVerifyTokenStringAccountVerified(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	_, email, _, _ := makeTestUser(t, &s, "", nil)
+	_, email, _, _ := makeTestUser(t, &s, nil, nil)
 
 	if err := s.UpdateVerifyTokenString(email, "abcd1234abcd1234abcd1234abcd1234"); err != ErrNoTokenForUser {
 		t.Fatalf(`UpdateVerifyTokenString error for already verified account: wanted "%+v", got "%+v."`, ErrNoTokenForUser, err)
@@ -372,7 +420,7 @@ func TestUpdateVerifyAccountSuccess(t *testing.T) {
 	verifyTokenString := auth.VerifyTokenString("abcd1234abcd1234abcd1234abcd1234")
 	time1 := time.Time{}
 
-	_, email, password, createdSeed := makeTestUser(t, &s, verifyTokenString, &time1)
+	_, email, password, createdSeed := makeTestUser(t, &s, &verifyTokenString, &time1)
 
 	// we're not testing normalization features so we'll just use this here
 	normEmail := email.Normalize()
@@ -380,7 +428,7 @@ func TestUpdateVerifyAccountSuccess(t *testing.T) {
 	if err := s.VerifyAccount(verifyTokenString); err != nil {
 		t.Fatalf("Unexpected error in VerifyAccount: err: %+v", err)
 	}
-	expectAccountMatch(t, &s, normEmail, email, password, createdSeed, "", nil)
+	expectAccountMatch(t, &s, normEmail, email, password, createdSeed, nil, nil)
 }
 
 // Test VerifyAccount for nonexisting token

store/auth_test.go

@@ -77,7 +77,7 @@ func TestStoreInsertToken(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// created for addition to the DB (no expiration attached)
 	authToken1 := auth.AuthToken{
@@ -123,7 +123,7 @@ func TestStoreUpdateToken(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// created for addition to the DB (no expiration attached)
 	authTokenUpdate := auth.AuthToken{
@@ -181,7 +181,7 @@ func TestStoreSaveToken(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// Version 1 of the token for both devices
 	// created for addition to the DB (no expiration attached)
@@ -274,7 +274,7 @@ func TestStoreGetToken(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// created for addition to the DB (no expiration attached)
 	authToken := auth.AuthToken{
@@ -327,7 +327,7 @@ func TestStoreTokenUTC(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	authToken := auth.AuthToken{
 		Token:    "seekrit-1",
@@ -394,7 +394,7 @@ func TestStoreTokenEmptyFields(t *testing.T) {
 			s, sqliteTmpFile := StoreTestInit(t)
 			defer StoreTestCleanup(sqliteTmpFile)
 
-			tc.authToken.UserId, _, _, _ = makeTestUser(t, &s, "", nil)
+			tc.authToken.UserId, _, _, _ = makeTestUser(t, &s, nil, nil)
 
 			var sqliteErr sqlite3.Error
 

store/password_test.go

@@ -16,7 +16,7 @@ func TestStoreChangePasswordSuccess(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	userId, email, oldPassword, _ := makeTestUser(t, &s, "", nil)
+	userId, email, oldPassword, _ := makeTestUser(t, &s, nil, nil)
 	token := auth.AuthTokenString("my-token")
 
 	_, err := s.db.Exec(
@@ -47,7 +47,7 @@ func TestStoreChangePasswordSuccess(t *testing.T) {
 		t.Errorf("ChangePasswordWithWallet (lower case email): unexpected error: %+v", err)
 	}
 
-	expectAccountMatch(t, &s, email.Normalize(), email, newPassword, newSeed, "", nil)
+	expectAccountMatch(t, &s, email.Normalize(), email, newPassword, newSeed, nil, nil)
 	expectWalletExists(t, &s, userId, encryptedWallet, sequence, hmac)
 	expectTokenNotExists(t, &s, token)
 
@@ -63,17 +63,18 @@ func TestStoreChangePasswordSuccess(t *testing.T) {
 		t.Errorf("ChangePasswordWithWallet (upper case email): unexpected error: %+v", err)
 	}
 
-	expectAccountMatch(t, &s, email.Normalize(), email, newNewPassword, newNewSeed, "", nil)
+	expectAccountMatch(t, &s, email.Normalize(), email, newNewPassword, newNewSeed, nil, nil)
 }
 
 func TestStoreChangePasswordErrors(t *testing.T) {
+	verifyToken := auth.VerifyTokenString("aoeu1234aoeu1234aoeu1234aoeu1234")
 	tt := []struct {
 		name              string
 		hasWallet         bool
 		sequence          wallet.Sequence
 		emailSuffix       auth.Email
 		oldPasswordSuffix auth.Password
-		verifyToken       auth.VerifyTokenString
+		verifyToken       *auth.VerifyTokenString
 		verifyExpiration  *time.Time
 		expectedError     error
 	}{
@@ -90,7 +91,7 @@ func TestStoreChangePasswordErrors(t *testing.T) {
 			sequence:          wallet.Sequence(2), // sequence is correct
 			emailSuffix:       auth.Email(""),     // the email is correct
 			oldPasswordSuffix: auth.Password(""),  // the password is correct
-			verifyToken:       auth.VerifyTokenString("aoeu1234aoeu1234aoeu1234aoeu1234"),
+			verifyToken:       &verifyToken,
 			verifyExpiration:  &time.Time{},
 			expectedError:     ErrNotVerified,
 		}, {
@@ -187,7 +188,7 @@ func TestStoreChangePasswordNoWalletSuccess(t *testing.T) {
 	s, sqliteTmpFile := StoreTestInit(t)
 	defer StoreTestCleanup(sqliteTmpFile)
 
-	userId, email, oldPassword, _ := makeTestUser(t, &s, "", nil)
+	userId, email, oldPassword, _ := makeTestUser(t, &s, nil, nil)
 	token := auth.AuthTokenString("my-token")
 
 	_, err := s.db.Exec(
@@ -207,7 +208,7 @@ func TestStoreChangePasswordNoWalletSuccess(t *testing.T) {
 		t.Errorf("ChangePasswordNoWallet (lower case email): unexpected error: %+v", err)
 	}
 
-	expectAccountMatch(t, &s, email.Normalize(), email, newPassword, newSeed, "", nil)
+	expectAccountMatch(t, &s, email.Normalize(), email, newPassword, newSeed, nil, nil)
 	expectWalletNotExists(t, &s, userId)
 	expectTokenNotExists(t, &s, token)
 
@@ -220,16 +221,18 @@ func TestStoreChangePasswordNoWalletSuccess(t *testing.T) {
 		t.Errorf("ChangePasswordNoWallet (upper case email): unexpected error: %+v", err)
 	}
 
-	expectAccountMatch(t, &s, email.Normalize(), email, newNewPassword, newNewSeed, "", nil)
+	expectAccountMatch(t, &s, email.Normalize(), email, newNewPassword, newNewSeed, nil, nil)
 }
 
 func TestStoreChangePasswordNoWalletErrors(t *testing.T) {
+	verifyToken := auth.VerifyTokenString("aoeu1234aoeu1234aoeu1234aoeu1234")
+
 	tt := []struct {
 		name              string
 		hasWallet         bool
 		emailSuffix       auth.Email
 		oldPasswordSuffix auth.Password
-		verifyToken       auth.VerifyTokenString
+		verifyToken       *auth.VerifyTokenString
 		verifyExpiration  *time.Time
 		expectedError     error
 	}{
@@ -250,7 +253,7 @@ func TestStoreChangePasswordNoWalletErrors(t *testing.T) {
 			hasWallet:         false,             // we don't have the wallet, as expected for this function
 			emailSuffix:       auth.Email(""),    // the email is correct
 			oldPasswordSuffix: auth.Password(""), // the password is correct
-			verifyToken:       auth.VerifyTokenString("aoeu1234aoeu1234aoeu1234aoeu1234"),
+			verifyToken:       &verifyToken,
 			verifyExpiration:  &time.Time{},
 			expectedError:     ErrNotVerified,
 		}, {

store/store.go

@@ -46,7 +46,7 @@ type StoreInterface interface {
 	SetWallet(auth.UserId, wallet.EncryptedWallet, wallet.Sequence, wallet.WalletHmac) error
 	GetWallet(auth.UserId) (wallet.EncryptedWallet, wallet.Sequence, wallet.WalletHmac, error)
 	GetUserId(auth.Email, auth.Password) (auth.UserId, error)
-	CreateAccount(auth.Email, auth.Password, auth.ClientSaltSeed, auth.VerifyTokenString) error
+	CreateAccount(auth.Email, auth.Password, auth.ClientSaltSeed, *auth.VerifyTokenString) error
 	UpdateVerifyTokenString(auth.Email, auth.VerifyTokenString) error
 	VerifyAccount(auth.VerifyTokenString) error
 	ChangePasswordWithWallet(auth.Email, auth.Password, auth.Password, auth.ClientSaltSeed, wallet.EncryptedWallet, wallet.Sequence, wallet.WalletHmac) error
@@ -125,7 +125,13 @@ func (s *Store) Migrate() error {
 			key TEXT NOT NULL,
 			client_salt_seed TEXT NOT NULL,
 			server_salt TEXT NOT NULL,
-			verify_token TEXT NOT NULL UNIQUE, -- will query by token when verifying
+
+			-- UNIQUE because we will query by token when verifying
+			--
+			-- Nullable because we want to use null to represent verified users. We can't use empty string
+			-- because multiple accounts with empty string will trigger the unique constraint, unlike null.
+			verify_token TEXT UNIQUE,
+
 			verify_expiration DATETIME,
 			user_id INTEGER PRIMARY KEY AUTOINCREMENT,
 			CHECK (
@@ -358,7 +364,7 @@ func (s *Store) GetUserId(email auth.Email, password auth.Password) (userId auth
 	var verified bool
 
 	err = s.db.QueryRow(
-		`SELECT user_id, key, server_salt, verify_token="" from accounts WHERE normalized_email=?`,
+		`SELECT user_id, key, server_salt, verify_token is null from accounts WHERE normalized_email=?`,
 		email.Normalize(),
 	).Scan(&userId, &key, &salt, &verified)
 	if err == sql.ErrNoRows {
@@ -383,14 +389,14 @@ func (s *Store) GetUserId(email auth.Email, password auth.Password) (userId auth
 // Account //
 /////////////
 
-func (s *Store) CreateAccount(email auth.Email, password auth.Password, seed auth.ClientSaltSeed, verifyToken auth.VerifyTokenString) (err error) {
+func (s *Store) CreateAccount(email auth.Email, password auth.Password, seed auth.ClientSaltSeed, verifyToken *auth.VerifyTokenString) (err error) {
 	key, salt, err := password.Create()
 	if err != nil {
 		return
 	}
 
 	var verifyExpiration *time.Time
-	if len(verifyToken) > 0 {
+	if verifyToken != nil {
 		verifyExpiration = new(time.Time)
 		*verifyExpiration = time.Now().UTC().Add(VerifyTokenLifespan)
 	}
@@ -420,7 +426,7 @@ func (s *Store) UpdateVerifyTokenString(email auth.Email, verifyTokenString auth
 	expiration := time.Now().UTC().Add(VerifyTokenLifespan)
 
 	res, err := s.db.Exec(
-		`UPDATE accounts SET verify_token=?, verify_expiration=? WHERE normalized_email=? and verify_token!=""`,
+		`UPDATE accounts SET verify_token=?, verify_expiration=? WHERE normalized_email=? and verify_token is not null`,
 		verifyTokenString, expiration, email.Normalize(),
 	)
 	if err != nil {
@@ -451,8 +457,8 @@ func (s *Store) UpdateVerifyTokenString(email auth.Email, verifyTokenString auth
 
 func (s *Store) VerifyAccount(verifyTokenString auth.VerifyTokenString) (err error) {
 	res, err := s.db.Exec(
-		"UPDATE accounts SET verify_token=?, verify_expiration=? WHERE verify_token=?",
+		"UPDATE accounts SET verify_token=null, verify_expiration=null WHERE verify_token=?",
-		"", nil, verifyTokenString,
+		verifyTokenString,
 	)
 	if err != nil {
 		return
@@ -553,7 +559,7 @@ func (s *Store) changePassword(
 	var verified bool
 
 	err = tx.QueryRow(
-		`SELECT user_id, key, server_salt, verify_token="" from accounts WHERE normalized_email=?`,
+		`SELECT user_id, key, server_salt, verify_token is null from accounts WHERE normalized_email=?`,
 		email.Normalize(),
 	).Scan(&userId, &oldKey, &oldSalt, &verified)
 	if err == sql.ErrNoRows {

store/store_test.go

@@ -37,7 +37,7 @@ func StoreTestCleanup(tmpFile *os.File) {
 func makeTestUser(
 	t *testing.T,
 	s *Store,
-	verifyToken auth.VerifyTokenString,
+	verifyToken *auth.VerifyTokenString,
 	verifyExpiration *time.Time,
 ) (userId auth.UserId, email auth.Email, password auth.Password, seed auth.ClientSaltSeed) {
 	// email with caps to trigger possible problems

store/wallet_test.go

@@ -86,7 +86,7 @@ func TestStoreInsertWallet(t *testing.T) {
 	defer StoreTestCleanup(sqliteTmpFile)
 
 	// Get a valid userId
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// Get a wallet, come back empty
 	expectWalletNotExists(t, &s, userId)
@@ -118,7 +118,7 @@ func TestStoreUpdateWallet(t *testing.T) {
 	defer StoreTestCleanup(sqliteTmpFile)
 
 	// Get a valid userId
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// Try to update a wallet, fail for nothing to update
 	if err := s.updateWalletToSequence(userId, wallet.EncryptedWallet("my-enc-wallet-a"), wallet.Sequence(1), wallet.WalletHmac("my-hmac-a")); err != ErrNoWallet {
@@ -174,7 +174,7 @@ func TestStoreSetWallet(t *testing.T) {
 	defer StoreTestCleanup(sqliteTmpFile)
 
 	// Get a valid userId
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// Sequence 2 - fails - out of sequence (behind the scenes, tries to update but there's nothing there yet)
 	if err := s.SetWallet(userId, wallet.EncryptedWallet("my-enc-wallet-a"), wallet.Sequence(2), wallet.WalletHmac("my-hmac-a")); err != ErrWrongSequence {
@@ -221,7 +221,7 @@ func TestStoreGetWallet(t *testing.T) {
 	defer StoreTestCleanup(sqliteTmpFile)
 
 	// Get a valid userId
-	userId, _, _, _ := makeTestUser(t, &s, "", nil)
+	userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 	// GetWallet fails when there's no wallet
 	encryptedWallet, sequence, hmac, err := s.GetWallet(userId)
@@ -264,7 +264,7 @@ func TestStoreWalletEmptyFields(t *testing.T) {
 			s, sqliteTmpFile := StoreTestInit(t)
 			defer StoreTestCleanup(sqliteTmpFile)
 
-			userId, _, _, _ := makeTestUser(t, &s, "", nil)
+			userId, _, _, _ := makeTestUser(t, &s, nil, nil)
 
 			var sqliteErr sqlite3.Error