use proper errors for db.Err

- switch to using errors.Is where applicable

internal/db/account.go

@@ -1,7 +1,7 @@
 package db
 
 import (
-	"fmt"
+	"errors"
 	"log"
 
 	"golang.org/x/crypto/bcrypt"
@@ -44,8 +44,8 @@ func (db *DBHandler) NewAccount(Login, Password string) (*Account, error) {
 }
 
 var (
-	ErrLoginInvalidID       = fmt.Errorf("invalid Login ID")
-	ErrLoginInvalidPassword = fmt.Errorf("invalid ID && Password combo")
+	ErrLoginInvalidID       = errors.New("invalid Login ID")
+	ErrLoginInvalidPassword = errors.New("invalid ID && Password combo")
 )
 
 func (db *DBHandler) TryLogin(Login, Password string) (*Account, error) {

internal/db/db_test.go

@@ -2,6 +2,7 @@ package db_test
 
 import (
 	"context"
+	"errors"
 	"os"
 	"testing"
 
@@ -50,7 +51,7 @@ func TestDBAccount(t *testing.T) {
 		t.Error("account username is not test")
 	}
 
-	if _, err = testDB.TryLogin("test", "wrongpassword"); err != db.ErrLoginInvalidPassword {
+	if _, err = testDB.TryLogin("test", "wrongpassword"); !errors.Is(err, db.ErrLoginInvalidPassword) {
 		t.Error("expected ErrLoginInvalidPassword")
 	}
 }

login/login.go

@@ -2,6 +2,7 @@ package login
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"log"
 	"math/rand"
@@ -79,7 +80,7 @@ func (server *LoginServer) Login(peer *protocol.CNPeer, _account interface{}, pk
 
 	// attempt login
 	account, err := server.dbHndlr.TryLogin(loginPkt.SzID, loginPkt.SzPassword)
-	if err == db.ErrLoginInvalidID {
+	if errors.Is(err, db.ErrLoginInvalidID) {
 		// this is the default behavior, auto create the account if the ID isn't in use
 		account, err = server.dbHndlr.NewAccount(loginPkt.SzID, loginPkt.SzPassword)
 		if err != nil {
@@ -87,7 +88,7 @@ func (server *LoginServer) Login(peer *protocol.CNPeer, _account interface{}, pk
 			SendError(LOGIN_DATABASE_ERROR)
 			return err
 		}
-	} else if err == db.ErrLoginInvalidPassword {
+	} else if errors.Is(err, db.ErrLoginInvalidPassword) {
 		// respond with invalid password
 		SendError(LOGIN_ID_AND_PASSWORD_DO_NOT_MATCH)
 		return nil