From b11dc1c84c17640bcc3d2ac9090472ce8119dc72 Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Thu, 5 May 2022 01:04:28 -0400
Subject: [PATCH] fix #1886

Add more clarify in NS INFO and SAREGISTER about unregistered nicknames
---
 irc/accounts.go | 18 +++++++++++++++++-
 irc/errors.go   |  1 +
 irc/handlers.go |  2 +-
 irc/nickserv.go |  8 +++++++-
 4 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/irc/accounts.go b/irc/accounts.go
index ce5f0e41..f4edeaa8 100644
--- a/irc/accounts.go
+++ b/irc/accounts.go
@@ -433,7 +433,7 @@ func (am *AccountManager) Register(client *Client, account string, callbackNames
 
 		// can't register an account with the same name as a registered nick
 		if am.NickToAccount(account) != "" {
-			return errAccountAlreadyRegistered
+			return errNameReserved
 		}
 
 		return am.server.store.Update(func(tx *buntdb.Tx) error {
@@ -1480,6 +1480,22 @@ func (am *AccountManager) LoadAccount(accountName string) (result ClientAccount,
 	return
 }
 
+func (am *AccountManager) accountWasUnregistered(accountName string) (result bool) {
+	casefoldedAccount, err := CasefoldName(accountName)
+	if err != nil {
+		return false
+	}
+
+	unregisteredKey := fmt.Sprintf(keyAccountUnregistered, casefoldedAccount)
+	am.server.store.View(func(tx *buntdb.Tx) error {
+		if _, err := tx.Get(unregisteredKey); err == nil {
+			result = true
+		}
+		return nil
+	})
+	return
+}
+
 // look up the unfolded version of an account name, possibly after deletion
 func (am *AccountManager) AccountToAccountName(account string) (result string) {
 	casefoldedAccount, err := CasefoldName(account)
diff --git a/irc/errors.go b/irc/errors.go
index f308121a..34f7fcdb 100644
--- a/irc/errors.go
+++ b/irc/errors.go
@@ -74,6 +74,7 @@ var (
 	errRegisteredOnly                 = errors.New("Cannot join registered-only channel without an account")
 	errValidEmailRequired             = errors.New("A valid email address is required for account registration")
 	errInvalidAccountRename           = errors.New("Account renames can only change the casefolding of the account name")
+	errNameReserved                   = errors.New(`Name reserved due to a prior registration`)
 )
 
 // String Errors
diff --git a/irc/handlers.go b/irc/handlers.go
index 0b5e470c..2fdece9c 100644
--- a/irc/handlers.go
+++ b/irc/handlers.go
@@ -69,7 +69,7 @@ func registrationErrorToMessage(config *Config, client *Client, err error) (mess
 	}
 
 	switch err {
-	case errAccountAlreadyRegistered, errAccountAlreadyVerified, errAccountAlreadyUnregistered, errAccountAlreadyLoggedIn, errAccountCreation, errAccountMustHoldNick, errAccountBadPassphrase, errCertfpAlreadyExists, errFeatureDisabled, errAccountBadPassphrase:
+	case errAccountAlreadyRegistered, errAccountAlreadyVerified, errAccountAlreadyUnregistered, errAccountAlreadyLoggedIn, errAccountCreation, errAccountMustHoldNick, errAccountBadPassphrase, errCertfpAlreadyExists, errFeatureDisabled, errAccountBadPassphrase, errNameReserved:
 		message = err.Error()
 	case errLimitExceeded:
 		message = `There have been too many registration attempts recently; try again later`
diff --git a/irc/nickserv.go b/irc/nickserv.go
index 44139359..d2c7dd60 100644
--- a/irc/nickserv.go
+++ b/irc/nickserv.go
@@ -913,7 +913,11 @@ func nsInfoHandler(service *ircService, server *Server, client *Client, command
 
 	account, err := server.accounts.LoadAccount(accountName)
 	if err != nil || !account.Verified {
-		service.Notice(rb, client.t("Account does not exist"))
+		if server.accounts.accountWasUnregistered(accountName) {
+			service.Notice(rb, client.t("Name reserved due to a prior registration"))
+		} else {
+			service.Notice(rb, client.t("Account does not exist"))
+		}
 		return
 	}
 
@@ -1025,6 +1029,8 @@ func nsSaregisterHandler(service *ircService, server *Server, client *Client, co
 		var errMsg string
 		if err == errAccountAlreadyRegistered || err == errAccountAlreadyVerified {
 			errMsg = client.t("Account already exists")
+		} else if err == errNameReserved {
+			errMsg = client.t(err.Error())
 		} else if err == errAccountBadPassphrase {
 			errMsg = client.t("Passphrase contains forbidden characters or is otherwise invalid")
 		} else {