remove debug only uses of linq

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNIPhysicalHandle.cs

@@ -5,9 +5,7 @@
 using System;
 using System.Diagnostics;
 using System.Threading;
-#if DEBUG
-using System.Linq;
-#endif
+using System.Collections.Generic;
 
 namespace Microsoft.Data.SqlClient.SNI
 {
@@ -85,12 +83,19 @@ public override void ReturnPacket(SNIPacket packet)
 #if DEBUG
         private string GetStackParts()
         {
-            return string.Join(Environment.NewLine,
-                Environment.StackTrace
-                .Split(new string[] { Environment.NewLine }, StringSplitOptions.None)
-                .Skip(3) // trims off the common parts at the top of the stack so you can see what the actual caller was
-                .Take(7) // trims off most of the bottom of the stack because when running under xunit there's a lot of spam
-            );
+            // trims off the common parts at the top of the stack so you can see what the actual caller was
+            // trims off most of the bottom of the stack because when running under xunit there's a lot of spam
+            string[] parts = Environment.StackTrace.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);
+            List<string> take = new List<string>(7);
+            for (int index = 0; take.Count < 7 && index < parts.Length; index++)
+            {
+                if (index > 2)
+                {
+                    take.Add(parts[index]);
+                }
+            }
+
+            return string.Join(Environment.NewLine, take.ToArray());
         }
 #endif
     }

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

@@ -9,9 +9,6 @@ namespace Microsoft.Data.Common
     using System.Collections.Generic;
     using System.Data;
     using System.Diagnostics;
-#if DEBUG
-    using System.Linq;
-#endif
     using System.Text;
     using Microsoft.Data.SqlClient;
 
@@ -312,7 +309,12 @@ private void ValidateCombinedSet(DBConnectionString componentSet, DBConnectionSt
                         // Component==Allow, Combined==Allow
                         // All values in the Combined Set should also be in the Component Set
                         // Combined - Component == null
-                        Debug.Assert(combinedSet._restrictionValues.Except(componentSet._restrictionValues).Count() == 0, "Combined set allows values not allowed by component set");
+#if DEBUG
+                        HashSet<string> combined = new HashSet<string>(combinedSet._restrictionValues);
+                        HashSet<string> component = new HashSet<string>(componentSet._restrictionValues);
+                        combined.ExceptWith(component);
+                        Debug.Assert(combined.Count == 0, "Combined set allows values not allowed by component set");
+#endif 
                     }
                     else if (combinedSet._behavior == KeyRestrictionBehavior.PreventUsage)
                     {
@@ -331,14 +333,24 @@ private void ValidateCombinedSet(DBConnectionString componentSet, DBConnectionSt
                         // Component==PreventUsage, Combined==Allow
                         // There shouldn't be any of the values from the Component Set in the Combined Set
                         // Intersect(Component, Combined) == null
-                        Debug.Assert(combinedSet._restrictionValues.Intersect(componentSet._restrictionValues).Count() == 0, "Combined values allows values prevented by component set");
+#if DEBUG
+                        HashSet<string> combined = new HashSet<string>(combinedSet._restrictionValues);
+                        HashSet<string> component = new HashSet<string>(componentSet._restrictionValues);
+                        combined.IntersectWith(component);
+                        Debug.Assert(combined.Count == 0, "Combined values allows values prevented by component set");
+#endif 
                     }
                     else if (combinedSet._behavior == KeyRestrictionBehavior.PreventUsage)
                     {
                         // Component==PreventUsage, Combined==PreventUsage
                         // All values in the Component Set should also be in the Combined Set
                         // Component - Combined == null
-                        Debug.Assert(componentSet._restrictionValues.Except(combinedSet._restrictionValues).Count() == 0, "Combined values does not prevent all of the values prevented by the component set");
+#if DEBUG
+                        HashSet<string> combined = new HashSet<string>(combinedSet._restrictionValues);
+                        HashSet<string> component = new HashSet<string>(componentSet._restrictionValues);
+                        component.IntersectWith(combined);
+                        Debug.Assert(component.Count == 0, "Combined values does not prevent all of the values prevented by the component set");
+#endif 
                     }
                     else
                     {

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs

@@ -5,9 +5,6 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-#if DEBUG
-using System.Linq;
-#endif
 using System.Runtime.CompilerServices;
 using System.Runtime.ConstrainedExecution;
 using System.Runtime.InteropServices;
@@ -3336,7 +3333,16 @@ internal void CloneCleanupAltMetaDataSetArray()
             internal void PushBuffer(byte[] buffer, int read)
             {
 #if DEBUG
-                Debug.Assert(!_snapshotInBuffs.Any(b => object.ReferenceEquals(b, buffer)));
+                if (_snapshotInBuffs != null && _snapshotInBuffs.Count > 0)
+                {
+                    foreach (PacketData packet in _snapshotInBuffs)
+                    {
+                        if (object.ReferenceEquals(packet.Buffer, buffer))
+                        {
+                            Debug.Assert(false,"buffer is already present in packet list");
+                        }
+                    }
+                }
 #endif
                 PacketData packetData = new PacketData();
                 packetData.Buffer = buffer;

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/VirtualSecureModeEnclaveProviderBase.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Linq;
 using System.Runtime.Caching;
 using System.Security.Cryptography;
 using System.Security.Cryptography.X509Certificates;
@@ -220,7 +219,17 @@ private X509Certificate2Collection GetSigningCertificate(string attestationUrl,
         // Checks if any certificates in the collection are expired
         private bool AnyCertificatesExpired(X509Certificate2Collection certificates)
         {
-            return certificates.OfType<X509Certificate2>().Any(c => c.NotAfter < DateTime.Now);
+            if (certificates != null)
+            {
+                foreach (object item in certificates)
+                {
+                    if (item is X509Certificate2 certificate && certificate.NotAfter < DateTime.Now)
+                    {
+                        return true;
+                    }
+                }
+            }
+            return false;
         }
 
         // Verifies that a chain of trust can be built from the health report provided
@@ -325,7 +334,31 @@ private void VerifyEnclavePolicy(EnclaveReportPackage enclaveReportPackage)
         // Verifies a byte[] enclave policy property
         private void VerifyEnclavePolicyProperty(string property, byte[] actual, byte[] expected)
         {
-            if (!actual.SequenceEqual(expected))
+            bool different = false;
+            if (actual == null || expected == null)
+            {
+                different = true;
+            }
+            else
+            {
+                if (actual.Length != expected.Length)
+                {
+                    different = true;
+                }
+                else
+                {
+                    for (int index = 0; index < actual.Length; index++)
+                    {
+                        if (actual[index] != expected[index])
+                        {
+                            different = true;
+                            break;
+                        }
+                    }
+                }
+            }
+
+            if (different)
             {
                 string exceptionMessage = String.Format(Strings.VerifyEnclavePolicyFailedFormat, property, BitConverter.ToString(actual), BitConverter.ToString(expected));
                 throw new ArgumentException(exceptionMessage);