From 4b66203dfc60083f60c82725c3586d854ee4e99f Mon Sep 17 00:00:00 2001
From: Kevin Cunnane <kcunnane@microsoft.com>
Date: Thu, 19 Oct 2017 10:42:26 -0700
Subject: [PATCH] Fix tools service crash + improve server edition naming
 (#506)

* Fix https://github.com/Microsoft/vscode-mssql/issues/986 and add better server edition naming
- Fixed a number of issues related to the binding queue, specifically the fact that it didn't capture exceptions that occurred on the binding thread. This caused the thread to crash the service.
  - The root cause of the error was when you get a connection error during init of the SmoMetadataProvider which threw an exception. Because of this no Binder was created, and the code would null ref later during processing
  - Added logic to handle null ref issue and other related code
  - Added a unit test for the new error handling path, and supported still returning some value in this case
- Separately, have a fix for an issue where the edition is shown as "SQL Azure" for all Azure connections. Fixing to be "Azure SQL DB" for this case and handle when the database reports as DW or Stretch instead. This maps better to users concept of what the edition should be and avoids returning what is an outdated term.

* Messed up the test - fixing this by returning the expected return object
---
 .../Connection/ConnectionService.cs           |  28 +++-
 .../LanguageServices/BindingQueue.cs          |  41 +++++-
 .../Completion/CompletionService.cs           |   5 +
 .../LanguageServices/ConnectedBindingQueue.cs |   1 +
 .../LanguageServices/LanguageService.cs       |  82 +++++++-----
 .../LanguageServices/QueueItem.cs             |   7 +
 .../Localization/sr.cs                        |  33 +++++
 .../Localization/sr.resx                      |  12 ++
 .../Localization/sr.strings                   |   5 +
 .../Localization/sr.xlf                       |  15 +++
 .../Scripting/ScriptingService.cs             |   4 +-
 .../sr.es.resx                                | 123 ------------------
 .../LanguageServer/PeekDefinitionTests.cs     |   1 +
 .../LanguageServer/BindingQueueTests.cs       |  30 +++++
 14 files changed, 222 insertions(+), 165 deletions(-)
 delete mode 100644 src/Microsoft.SqlTools.ServiceLayer/sr.es.resx

diff --git a/src/Microsoft.SqlTools.ServiceLayer/Connection/ConnectionService.cs b/src/Microsoft.SqlTools.ServiceLayer/Connection/ConnectionService.cs
index ef2e59d2..2d7acbde 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/Connection/ConnectionService.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/Connection/ConnectionService.cs
@@ -29,6 +29,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Connection
     public class ConnectionService
     {
         public const string AdminConnectionPrefix = "ADMIN:";
+        private const string SqlAzureEdition = "SQL Azure";
 
         /// <summary>
         /// Singleton service instance
@@ -456,7 +457,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Connection
                     EngineEditionId = serverInfo.EngineEditionId,
                     ServerVersion = serverInfo.ServerVersion,
                     ServerLevel = serverInfo.ServerLevel,
-                    ServerEdition = serverInfo.ServerEdition,
+                    ServerEdition = MapServerEdition(serverInfo),
                     IsCloud = serverInfo.IsCloud,
                     AzureVersion = serverInfo.AzureVersion,
                     OsVersion = serverInfo.OsVersion,
@@ -474,6 +475,31 @@ namespace Microsoft.SqlTools.ServiceLayer.Connection
             return response;
         }
 
+        private string MapServerEdition(ReliableConnectionHelper.ServerInfo serverInfo)
+        {
+            string serverEdition = serverInfo.ServerEdition;
+            if (string.IsNullOrWhiteSpace(serverEdition))
+            {
+                return string.Empty;
+            }
+            if (SqlAzureEdition.Equals(serverEdition, StringComparison.OrdinalIgnoreCase))
+            {
+                switch(serverInfo.EngineEditionId)
+                {
+                    case (int) DatabaseEngineEdition.SqlDataWarehouse:
+                        serverEdition = SR.AzureSqlDwEdition;
+                        break;
+                    case (int) DatabaseEngineEdition.SqlStretchDatabase:
+                        serverEdition = SR.AzureSqlStretchEdition;
+                        break;
+                    default:
+                        serverEdition =  SR.AzureSqlDbEdition;
+                        break;
+                }
+            }
+            return serverEdition;
+        }
+
         /// <summary>
         /// Tries to create and open a connection with the given ConnectParams.
         /// </summary>
diff --git a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/BindingQueue.cs b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/BindingQueue.cs
index b8584e77..b57f960f 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/BindingQueue.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/BindingQueue.cs
@@ -9,6 +9,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.SqlTools.Utility;
 using System.Linq;
+using Microsoft.SqlTools.ServiceLayer.Utility;
 
 namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
 {    
@@ -64,6 +65,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
             string key,
             Func<IBindingContext, CancellationToken, object> bindOperation,
             Func<IBindingContext, object> timeoutOperation = null,
+            Func<Exception, object> errorHandler = null,
             int? bindingTimeout = null,
             int? waitForLockTimeout = null)
         {
@@ -78,6 +80,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                 Key = key,
                 BindOperation = bindOperation,
                 TimeoutOperation = timeoutOperation,
+                ErrorHandler = errorHandler,
                 BindingTimeout = bindingTimeout,
                 WaitForLockTimeout = waitForLockTimeout
             };
@@ -92,6 +95,23 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
             return queueItem;
         }
 
+        /// <summary>
+        /// Checks if a particular binding context is connected or not
+        /// </summary>
+        /// <param name="key"></param>
+        public bool IsBindingContextConnected(string key)
+        {
+            lock (this.bindingContextLock)
+            {
+                IBindingContext context;
+                if (this.BindingContextMap.TryGetValue(key, out context))
+                {
+                    return context.IsConnected;
+                }
+                return false;
+            } 
+        }
+
         /// <summary>
         /// Gets or creates a binding context for the provided context key
         /// </summary>
@@ -270,9 +290,20 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                             // run the operation in a separate thread
                             var bindThread = new Thread(() =>
                             {
-                                result = queueItem.BindOperation(
-                                     bindingContext,
-                                     cancelToken.Token); 
+                                try
+                                {
+                                    result = queueItem.BindOperation(
+                                        bindingContext,
+                                        cancelToken.Token);
+                                }
+                                catch (Exception ex)
+                                {
+                                    Logger.Write(LogLevel.Error, "Unexpected exception on the binding queue: " + ex.ToString());
+                                    if (queueItem.ErrorHandler != null)
+                                    {
+                                        result = queueItem.ErrorHandler(ex);
+                                    }
+                                }
                             }, BindingQueue<T>.QueueThreadStackSize);
                             bindThread.Start();
 
@@ -282,7 +313,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                                 queueItem.Result = result;
                             }
                             else
-                            {       
+                            {
                                 cancelToken.Cancel();
 
                                 // if the task didn't complete then call the timeout callback
@@ -298,7 +329,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                                     // wait for the operation to complete before releasing the lock
                                     bindThread.Join();
                                     bindingContext.BindingLock.Set();
-                                });
+                                }).ContinueWithOnFaulted(t => Logger.Write(LogLevel.Error, "Binding queue threw exception " + t.Exception.ToString()));
                             }
                         }
                         catch (Exception ex)
diff --git a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Completion/CompletionService.cs b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Completion/CompletionService.cs
index cf7eb6c3..9de595d3 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Completion/CompletionService.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Completion/CompletionService.cs
@@ -104,6 +104,11 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices.Completion
                 {
                     // return the default list if the connected bind fails
                     return CreateDefaultCompletionItems(scriptParseInfo, scriptDocumentInfo, useLowerCaseSuggestions);
+                },
+                errorHandler: ex =>
+                {
+                    // return the default list if an unexpected exception occurs
+                    return CreateDefaultCompletionItems(scriptParseInfo, scriptDocumentInfo, useLowerCaseSuggestions);
                 });
             return queueItem;
         }
diff --git a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/ConnectedBindingQueue.cs b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/ConnectedBindingQueue.cs
index 1a427251..ce48c512 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/ConnectedBindingQueue.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/ConnectedBindingQueue.cs
@@ -27,6 +27,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
             string key,
             Func<IBindingContext, CancellationToken, object> bindOperation,
             Func<IBindingContext, object> timeoutOperation = null,
+            Func<Exception, object> errorHandler = null,
             int? bindingTimeout = null,
             int? waitForLockTimeout = null);
     }
diff --git a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/LanguageService.cs b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/LanguageService.cs
index 96fe16cd..d19f24c9 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/LanguageService.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/LanguageService.cs
@@ -794,10 +794,13 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
 
                                     List<ParseResult> parseResults = new List<ParseResult>();
                                     parseResults.Add(parseResult);
-                                    bindingContext.Binder.Bind(
-                                        parseResults,
-                                        connInfo.ConnectionDetails.DatabaseName,
-                                        BindMode.Batch);
+                                    if (bindingContext.IsConnected && bindingContext.Binder != null)
+                                    {
+                                        bindingContext.Binder.Bind(
+                                            parseResults,
+                                            connInfo.ConnectionDetails.DatabaseName,
+                                            BindMode.Batch);
+                                    }
                                 }
                                 catch (ConnectionException)
                                 {
@@ -856,8 +859,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                     try
                     {
                         scriptInfo.ConnectionKey = this.BindingQueue.AddConnectionContext(info, "languageService");
-                        scriptInfo.IsConnected = true;
-
+                        scriptInfo.IsConnected = this.BindingQueue.IsBindingContextConnected(scriptInfo.ConnectionKey);
                     }
                     catch (Exception ex)
                     {
@@ -917,40 +919,42 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                                 ParseResult parseResult = Parser.Parse(
                                     "select ",
                                     bindingContext.ParseOptions);
+                                if (bindingContext.IsConnected && bindingContext.Binder != null)
+                                {
+                                    List<ParseResult> parseResults = new List<ParseResult>();
+                                    parseResults.Add(parseResult);
+                                    bindingContext.Binder.Bind(
+                                        parseResults,
+                                        info.ConnectionDetails.DatabaseName,
+                                        BindMode.Batch);
 
-                                List<ParseResult> parseResults = new List<ParseResult>();
-                                parseResults.Add(parseResult);
-                                bindingContext.Binder.Bind(
-                                    parseResults,
-                                    info.ConnectionDetails.DatabaseName,
-                                    BindMode.Batch);
+                                    // get the completion list from SQL Parser
+                                    var suggestions = Resolver.FindCompletions(
+                                        parseResult, 1, 8,
+                                        bindingContext.MetadataDisplayInfoProvider);
 
-                                // get the completion list from SQL Parser
-                                var suggestions = Resolver.FindCompletions(
-                                    parseResult, 1, 8,
-                                    bindingContext.MetadataDisplayInfoProvider);
+                                    // this forces lazy evaluation of the suggestion metadata
+                                    AutoCompleteHelper.ConvertDeclarationsToCompletionItems(suggestions, 1, 8, 8);
 
-                                // this forces lazy evaluation of the suggestion metadata
-                                AutoCompleteHelper.ConvertDeclarationsToCompletionItems(suggestions, 1, 8, 8);
+                                    parseResult = Parser.Parse(
+                                        "exec ",
+                                        bindingContext.ParseOptions);
 
-                                parseResult = Parser.Parse(
-                                    "exec ",
-                                    bindingContext.ParseOptions);
+                                    parseResults = new List<ParseResult>();
+                                    parseResults.Add(parseResult);
+                                    bindingContext.Binder.Bind(
+                                        parseResults,
+                                        info.ConnectionDetails.DatabaseName,
+                                        BindMode.Batch);
 
-                                parseResults = new List<ParseResult>();
-                                parseResults.Add(parseResult);
-                                bindingContext.Binder.Bind(
-                                    parseResults,
-                                    info.ConnectionDetails.DatabaseName,
-                                    BindMode.Batch);
+                                    // get the completion list from SQL Parser
+                                    suggestions = Resolver.FindCompletions(
+                                        parseResult, 1, 6,
+                                        bindingContext.MetadataDisplayInfoProvider);
 
-                                // get the completion list from SQL Parser
-                                suggestions = Resolver.FindCompletions(
-                                    parseResult, 1, 6,
-                                    bindingContext.MetadataDisplayInfoProvider);
-
-                                // this forces lazy evaluation of the suggestion metadata
-                                AutoCompleteHelper.ConvertDeclarationsToCompletionItems(suggestions, 1, 6, 6);
+                                    // this forces lazy evaluation of the suggestion metadata
+                                    AutoCompleteHelper.ConvertDeclarationsToCompletionItems(suggestions, 1, 6, 6);
+                                }
                                 return null;
                             });
 
@@ -1103,6 +1107,16 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                         Message = SR.PeekDefinitionTimedoutError,
                         Locations = null
                     };
+                },
+                errorHandler: ex =>
+                {
+                    // return error result
+                    return new DefinitionResult
+                    {
+                        IsErrorResult = true,
+                        Message = ex.Message,
+                        Locations = null
+                    };
                 });
                            
             // wait for the queue item
diff --git a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/QueueItem.cs b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/QueueItem.cs
index 2b45de8b..30cc3548 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/QueueItem.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/LanguageServices/QueueItem.cs
@@ -36,6 +36,13 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
         /// </summary>
         public Func<IBindingContext, object> TimeoutOperation { get; set; }
 
+        /// <summary>
+        /// Gets or sets the operation to call if the bind operation encounters an unexpected exception.
+        /// Supports returning an object in case of the exception occurring since in some cases we need to be
+        /// tolerant of error cases and still return some value
+        /// </summary>
+        public Func<Exception, object> ErrorHandler { get; set; }
+
         /// <summary>
         /// Gets or sets an event to signal when this queue item has been processed
         /// </summary>
diff --git a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.cs b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.cs
index 6cfb1c95..a3fdb6bf 100755
--- a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.cs
@@ -77,6 +77,30 @@ namespace Microsoft.SqlTools.ServiceLayer
             }
         }
 
+        public static string AzureSqlDbEdition
+        {
+            get
+            {
+                return Keys.GetString(Keys.AzureSqlDbEdition);
+            }
+        }
+
+        public static string AzureSqlDwEdition
+        {
+            get
+            {
+                return Keys.GetString(Keys.AzureSqlDwEdition);
+            }
+        }
+
+        public static string AzureSqlStretchEdition
+        {
+            get
+            {
+                return Keys.GetString(Keys.AzureSqlStretchEdition);
+            }
+        }
+
         public static string QueryServiceCancelAlreadyCompleted
         {
             get
@@ -3652,6 +3676,15 @@ namespace Microsoft.SqlTools.ServiceLayer
             public const string ConnectionParamsValidateNullSqlAuth = "ConnectionParamsValidateNullSqlAuth";
 
 
+            public const string AzureSqlDbEdition = "AzureSqlDbEdition";
+
+
+            public const string AzureSqlDwEdition = "AzureSqlDwEdition";
+
+
+            public const string AzureSqlStretchEdition = "AzureSqlStretchEdition";
+
+
             public const string QueryServiceCancelAlreadyCompleted = "QueryServiceCancelAlreadyCompleted";
 
 
diff --git a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.resx b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.resx
index d83ce345..88515160 100755
--- a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.resx
+++ b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.resx
@@ -166,6 +166,18 @@
     <comment>.
  Parameters: 0 - component (string) </comment>
   </data>
+  <data name="AzureSqlDbEdition" xml:space="preserve">
+    <value>Azure SQL DB</value>
+    <comment></comment>
+  </data>
+  <data name="AzureSqlDwEdition" xml:space="preserve">
+    <value>Azure SQL Data Warehouse</value>
+    <comment></comment>
+  </data>
+  <data name="AzureSqlStretchEdition" xml:space="preserve">
+    <value>Azure SQL Stretch Database</value>
+    <comment></comment>
+  </data>
   <data name="QueryServiceCancelAlreadyCompleted" xml:space="preserve">
     <value>The query has already completed, it cannot be cancelled</value>
     <comment></comment>
diff --git a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings
index c1e00cda..fe050287 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings
+++ b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings
@@ -47,6 +47,11 @@ ConnectionParamsValidateNullServerName = ServerName cannot be null or empty
 
 ConnectionParamsValidateNullSqlAuth(string component) = {0} cannot be null or empty when using SqlLogin authentication
 
+### General connection service strings
+AzureSqlDbEdition = Azure SQL DB
+AzureSqlDwEdition = Azure SQL Data Warehouse
+AzureSqlStretchEdition = Azure SQL Stretch Database
+
 ############################################################################
 # Query Execution Service
 
diff --git a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.xlf b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.xlf
index 8c452ae5..5d8d3424 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.xlf
+++ b/src/Microsoft.SqlTools.ServiceLayer/Localization/sr.xlf
@@ -2280,6 +2280,21 @@
         <target state="new">Never</target>
         <note></note>
       </trans-unit>
+      <trans-unit id="AzureSqlDbEdition">
+        <source>Azure SQL DB</source>
+        <target state="new">Azure SQL DB</target>
+        <note></note>
+      </trans-unit>
+      <trans-unit id="AzureSqlDwEdition">
+        <source>Azure SQL Data Warehouse</source>
+        <target state="new">Azure SQL Data Warehouse</target>
+        <note></note>
+      </trans-unit>
+      <trans-unit id="AzureSqlStretchEdition">
+        <source>Azure SQL Stretch Database</source>
+        <target state="new">Azure SQL Stretch Database</target>
+        <note></note>
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file
diff --git a/src/Microsoft.SqlTools.ServiceLayer/Scripting/ScriptingService.cs b/src/Microsoft.SqlTools.ServiceLayer/Scripting/ScriptingService.cs
index d24aa9b0..c173df87 100644
--- a/src/Microsoft.SqlTools.ServiceLayer/Scripting/ScriptingService.cs
+++ b/src/Microsoft.SqlTools.ServiceLayer/Scripting/ScriptingService.cs
@@ -238,7 +238,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
                     string script = string.Empty;
                     ScriptingObject scriptingObject = parameters.ScriptingObjects[0];
                     try
-                    {                          
+                    {
                         Server server = new Server(bindingContext.ServerConnection);
                         server.DefaultTextMode = true;
 
@@ -277,7 +277,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
                     }
 
                     return null;
-                });                     
+                });
         }
 
         /// <summary>
diff --git a/src/Microsoft.SqlTools.ServiceLayer/sr.es.resx b/src/Microsoft.SqlTools.ServiceLayer/sr.es.resx
deleted file mode 100644
index b1657f70..00000000
--- a/src/Microsoft.SqlTools.ServiceLayer/sr.es.resx
+++ /dev/null
@@ -1,123 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="TestLocalizationConstant" xml:space="preserve">
-    <value>ES_LOCALIZATION</value>
-  </data>
-</root>
\ No newline at end of file
diff --git a/test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/LanguageServer/PeekDefinitionTests.cs b/test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/LanguageServer/PeekDefinitionTests.cs
index d32a51b8..9bf09da7 100644
--- a/test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/LanguageServer/PeekDefinitionTests.cs
+++ b/test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/LanguageServer/PeekDefinitionTests.cs
@@ -211,6 +211,7 @@ GO";
                 It.IsAny<string>(),
                 It.IsAny<Func<IBindingContext, CancellationToken, object>>(),
                 It.IsAny<Func<IBindingContext, object>>(),
+                It.IsAny<Func<Exception, object>>(),
                 It.IsAny<int?>(),
                 It.IsAny<int?>()))
             .Callback<string, Func<IBindingContext, CancellationToken, object>, Func<IBindingContext, object>, int?, int?>(
diff --git a/test/Microsoft.SqlTools.ServiceLayer.UnitTests/LanguageServer/BindingQueueTests.cs b/test/Microsoft.SqlTools.ServiceLayer.UnitTests/LanguageServer/BindingQueueTests.cs
index 3b1653c0..06d03641 100644
--- a/test/Microsoft.SqlTools.ServiceLayer.UnitTests/LanguageServer/BindingQueueTests.cs
+++ b/test/Microsoft.SqlTools.ServiceLayer.UnitTests/LanguageServer/BindingQueueTests.cs
@@ -3,6 +3,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 //
 
+using System;
 using System.Threading;
 using Microsoft.SqlServer.Management.Common;
 using Microsoft.SqlServer.Management.SmoMetadataProvider;
@@ -133,6 +134,35 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.LanguageServer
             Assert.False(this.isCancelationRequested);
         }
 
+        /// <summary>
+        /// Queues a single task
+        /// </summary>
+        [Fact]
+        public void QueueWithUnhandledExceptionTest()
+        {
+            InitializeTestSettings();
+            ManualResetEvent mre = new ManualResetEvent(false);
+            bool isExceptionHandled = false;
+            object defaultReturnObject = new object();
+            var queueItem = this.bindingQueue.QueueBindingOperation(
+                key: "testkey",
+                bindOperation: (context, CancellationToken) => throw new Exception("Unhandled!!"),
+                timeoutOperation: TestTimeoutOperation,
+                errorHandler: (exception) => {
+                    isExceptionHandled = true;
+                    mre.Set();
+                    return defaultReturnObject;
+                });
+
+            mre.WaitOne(10000);
+            
+            this.bindingQueue.StopQueueProcessor(15000);
+
+            Assert.True(isExceptionHandled);
+            var result = queueItem.GetResultAsT<object>();
+            Assert.Equal(defaultReturnObject, result);
+        }
+
         /// <summary>
         /// Queue a 100 short tasks
         /// </summary>