Remove Linq + validator updates

Author: cheenamalhotra

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/Common/DbConnectionStringCommon.cs

@@ -98,6 +98,7 @@ internal static string ConvertToString(object value)
 
         private const string ApplicationIntentReadWriteString = "ReadWrite";
         private const string ApplicationIntentReadOnlyString = "ReadOnly";
+        const string NotSpecifiedString = "Not Specified";
         const string SqlPasswordString = "Sql Password";
         const string ActiveDirectoryPasswordString = "Active Directory Password";
         const string ActiveDirectoryIntegratedString = "Active Directory Integrated";
@@ -108,12 +109,41 @@ internal static string ConvertToString(object value)
         internal const string ActiveDirectoryMSIString = "Active Directory MSI";
         internal const string ActiveDirectoryDefaultString = "Active Directory Default";
 
+        private static bool IsValidAuthenticationMethodEnum()
+        {
+            string[] names = Enum.GetNames(typeof(SqlAuthenticationMethod));
+            string[] supportedList =
+            {
+                NotSpecifiedString,
+                SqlPasswordString,
+                ActiveDirectoryPasswordString,
+                ActiveDirectoryIntegratedString,
+                ActiveDirectoryInteractiveString,
+                ActiveDirectoryServicePrincipalString,
+                ActiveDirectoryDeviceCodeFlowString,
+                ActiveDirectoryManagedIdentityString,
+                ActiveDirectoryMSIString,
+                ActiveDirectoryDefaultString
+            };
+            bool listValid;
+            if (listValid = names.Length == supportedList.Length)
+            {
+                for (int i = 0; i < supportedList.Length; i++)
+                {
+                    if (supportedList[i].CompareTo(names[i]) == 0)
+                    {
+                        listValid = false;
+                    }
+                }
+            }
+            return listValid;
+        }
+
         internal static bool TryConvertToAuthenticationType(string value, out SqlAuthenticationMethod result)
         {
-            Debug.Assert(Enum.GetNames(typeof(SqlAuthenticationMethod)).Length == 10, "SqlAuthenticationMethod enum has changed, update needed");
+            Debug.Assert(IsValidAuthenticationMethodEnum(), "SqlAuthenticationMethod enum has changed, update needed");
 
             bool isSuccess = false;
-
             if (StringComparer.InvariantCultureIgnoreCase.Equals(value, SqlPasswordString)
                 || StringComparer.InvariantCultureIgnoreCase.Equals(value, Convert.ToString(SqlAuthenticationMethod.SqlPassword, CultureInfo.InvariantCulture)))
             {
@@ -508,7 +538,7 @@ internal static ApplicationIntent ConvertToApplicationIntent(string keyword, obj
 
         internal static bool IsValidAuthenticationTypeValue(SqlAuthenticationMethod value)
         {
-            Debug.Assert(Enum.GetNames(typeof(SqlAuthenticationMethod)).Length == 9, "SqlAuthenticationMethod enum has changed, update needed");
+            Debug.Assert(Enum.GetNames(typeof(SqlAuthenticationMethod)).Length == 10, "SqlAuthenticationMethod enum has changed, update needed");
             return value == SqlAuthenticationMethod.SqlPassword
                 || value == SqlAuthenticationMethod.ActiveDirectoryPassword
                 || value == SqlAuthenticationMethod.ActiveDirectoryIntegrated

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/Common/DbConnectionStringCommon.cs

@@ -516,6 +516,7 @@ internal static ApplicationIntent ConvertToApplicationIntent(string keyword, obj
             }
         }
 
+        const string NotSpecifiedString = "Not Specified";
         const string SqlPasswordString = "Sql Password";
         const string ActiveDirectoryPasswordString = "Active Directory Password";
         const string ActiveDirectoryIntegratedString = "Active Directory Integrated";
@@ -525,11 +526,41 @@ internal static ApplicationIntent ConvertToApplicationIntent(string keyword, obj
         internal const string ActiveDirectoryManagedIdentityString = "Active Directory Managed Identity";
         internal const string ActiveDirectoryMSIString = "Active Directory MSI";
         internal const string ActiveDirectoryDefaultString = "Active Directory Default";
-        const string SqlCertificateString = "Sql Certificate";
+        // const string SqlCertificateString = "Sql Certificate";
+
+        private static bool IsValidAuthenticationMethodEnum()
+        {
+            string[] names = Enum.GetNames(typeof(SqlAuthenticationMethod));
+            string[] supportedList =
+            {
+                NotSpecifiedString,
+                SqlPasswordString,
+                ActiveDirectoryPasswordString,
+                ActiveDirectoryIntegratedString,
+                ActiveDirectoryInteractiveString,
+                ActiveDirectoryServicePrincipalString,
+                ActiveDirectoryDeviceCodeFlowString,
+                ActiveDirectoryManagedIdentityString,
+                ActiveDirectoryMSIString,
+                ActiveDirectoryDefaultString
+            };
+            bool listValid;
+            if (listValid = names.Length == supportedList.Length)
+            {
+                for (int i = 0; i < supportedList.Length; i++)
+                {
+                    if (supportedList[i].CompareTo(names[i]) == 0)
+                    {
+                        listValid = false;
+                    }
+                }
+            }
+            return listValid;
+        }
 
         internal static bool TryConvertToAuthenticationType(string value, out SqlAuthenticationMethod result)
         {
-            Debug.Assert(Enum.GetNames(typeof(SqlAuthenticationMethod)).Length == 10, "SqlAuthenticationMethod enum has changed, update needed");
+            Debug.Assert(IsValidAuthenticationMethodEnum(), "SqlAuthenticationMethod enum has changed, update needed");
 
             bool isSuccess = false;
 

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ActiveDirectoryAuthenticationProvider.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.Collections.Concurrent;
-using System.Linq;
 using System.Security;
 using System.Threading;
 using System.Threading.Tasks;
@@ -215,15 +214,28 @@ public override async Task<SqlAuthenticationToken> AcquireTokenAsync(SqlAuthenti
                      parameters.AuthenticationMethod == SqlAuthenticationMethod.ActiveDirectoryDeviceCodeFlow)
             {
                 // Fetch available accounts from 'app' instance
-                System.Collections.Generic.IEnumerable<IAccount> accounts = await app.GetAccountsAsync();
-                IAccount account;
-                if (!string.IsNullOrEmpty(parameters.UserId))
+                System.Collections.Generic.IEnumerator<IAccount> accounts = (await app.GetAccountsAsync()).GetEnumerator();
+                
+                IAccount account = default;
+                if (accounts.MoveNext())
                 {
-                    account = accounts.FirstOrDefault(a => parameters.UserId.Equals(a.Username, StringComparison.InvariantCultureIgnoreCase));
-                }
-                else
-                {
-                    account = accounts.FirstOrDefault();
+                    if (!string.IsNullOrEmpty(parameters.UserId))
+                    {
+                        do
+                        {
+                            IAccount currentVal = accounts.Current;
+                            if (string.Compare(parameters.UserId, currentVal.Username, StringComparison.InvariantCultureIgnoreCase) == 0)
+                            {
+                                account = currentVal;
+                                break;
+                            }
+                        }
+                        while (accounts.MoveNext());
+                    }
+                    else
+                    {
+                        account = accounts.Current;
+                    }
                 }
 
                 if (null != account)

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/ConnectivityTests/AADConnectionTest.cs

@@ -465,7 +465,6 @@ public static void ActiveDirectoryDefaultWithPasswordMustFail()
         [ConditionalFact(nameof(IsAADConnStringsSetup))]
         public static void ActiveDirectoryDefaultMustPass()
         {
-            // connection fails with expected error message.
             string[] credKeys = { "Authentication", "User ID", "Password", "UID", "PWD" };
             string connStr = DataTestUtility.RemoveKeysInConnStr(DataTestUtility.AADPasswordConnectionString, credKeys) +
                 "Authentication=ActiveDirectoryDefault;";