Edit Data: Better errors for possible truncation (#514)

* Fix to make sql exceptions surface properly to user (with important notes!)

* Adding support for detecting column size issues when updating a cell

* Adding unit tests for the exception on read scenario

src/Microsoft.SqlTools.ServiceLayer/EditData/UpdateManagement/CellUpdate.cs

@@ -49,10 +49,7 @@ namespace Microsoft.SqlTools.ServiceLayer.EditData.UpdateManagement
             }
             else if (columnType == typeof(string))
             {
-                // Special case for strings because the string value should stay the same as provided
-                // If user typed 'NULL' they mean NULL as text
-                Value = valueAsString == TextNullString ? NullString : valueAsString;
-                ValueAsString = valueAsString;
+                ProcessTextCell(valueAsString);
             }
             else if (columnType == typeof(Guid))
             {
@@ -245,6 +242,23 @@ namespace Microsoft.SqlTools.ServiceLayer.EditData.UpdateManagement
             ValueAsString = NullString;
         }
 
+        private void ProcessTextCell(string valueAsString)
+        {
+            // Special case for strings because the string value should stay the same as provided
+            // If user typed 'NULL' they mean NULL as text
+            Value = valueAsString == TextNullString ? NullString : valueAsString;
+            
+            // Make sure that the value fits inside the size of the column
+            if (Column.ColumnSize.HasValue && valueAsString.Length > Column.ColumnSize)
+            {
+                string columnSizeString = $"({Column.ColumnSize.Value})";
+                string columnTypeString = Column.DataTypeName.ToUpperInvariant() + columnSizeString;
+                throw new FormatException(SR.EditDataValueTooLarge(valueAsString, columnTypeString));
+            }
+            
+            ValueAsString = valueAsString;
+        }
+
         #endregion
     }
 }

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.cs

@@ -3651,6 +3651,11 @@ namespace Microsoft.SqlTools.ServiceLayer
             return Keys.GetString(Keys.EditDataUnsupportedObjectType, typeName);
         }
 
+        public static string EditDataValueTooLarge(string value, string columnType)
+        {
+            return Keys.GetString(Keys.EditDataValueTooLarge, value, columnType);
+        }
+
         [System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
         public class Keys
         {
@@ -3932,6 +3937,9 @@ namespace Microsoft.SqlTools.ServiceLayer
             public const string EditDataNullNotAllowed = "EditDataNullNotAllowed";
 
 
+            public const string EditDataValueTooLarge = "EditDataValueTooLarge";
+
+
             public const string EE_BatchSqlMessageNoProcedureInfo = "EE_BatchSqlMessageNoProcedureInfo";
 
 

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.resx

@@ -495,6 +495,11 @@
     <value>NULL is not allowed for this column</value>
     <comment></comment>
   </data>
+  <data name="EditDataValueTooLarge" xml:space="preserve">
+    <value>Value {0} is too large to fit in column of type {1}</value>
+    <comment>.
+ Parameters: 0 - value (string), 1 - columnType (string) </comment>
+  </data>
   <data name="EE_BatchSqlMessageNoProcedureInfo" xml:space="preserve">
     <value>Msg {0}, Level {1}, State {2}, Line {3}</value>
     <comment></comment>

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings

@@ -232,6 +232,8 @@ EditDataTimeOver24Hrs = TIME column values must be between 00:00:00.0000000 and
 
 EditDataNullNotAllowed = NULL is not allowed for this column
 
+EditDataValueTooLarge(string value, string columnType) = Value {0} is too large to fit in column of type {1}
+
 ############################################################################
 # DacFx Resources
 

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.xlf

@@ -2305,6 +2305,12 @@
         <target state="new">For directory {0} a file with name {1} already exists</target>
         <note></note>
       </trans-unit>
+      <trans-unit id="EditDataValueTooLarge">
+        <source>Value {0} is too large to fit in column of type {1}</source>
+        <target state="new">Value {0} is too large to fit in column of type {1}</target>
+        <note>.
+ Parameters: 0 - value (string), 1 - columnType (string) </note>
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/ResultSet.cs

@@ -616,19 +616,23 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
             {
                 throw new InvalidOperationException(SR.QueryServiceResultSetNotRead);
             }
-            if (!dbDataReader.HasRows)
+            // NOTE: We are no longer checking to see if the data reader has rows before reading 
+            // b/c of a quirk in SqlClient. In some scenarios, a SqlException isn't thrown until we
+            // read. In order to get appropriate errors back to the user, we'll read first.
+            // Returning false from .ReadAsync means there aren't any rows.
+
+            // Create a storage data reader, read it, make sure there were results
+            StorageDataReader dataReader = new StorageDataReader(dbDataReader);
+            if (!await dataReader.ReadAsync(CancellationToken.None))
             {
                 throw new InvalidOperationException(SR.QueryServiceResultSetAddNoRows);
             }
-
-            StorageDataReader dataReader = new StorageDataReader(dbDataReader);
-
+            
             using (IFileStreamWriter writer = fileStreamFactory.GetWriter(outputFileName))
             {
                 // Write the row to the end of the file
                 long currentFileOffset = totalBytesWritten;
                 writer.Seek(currentFileOffset);
-                await dataReader.ReadAsync(CancellationToken.None);
                 totalBytesWritten += writer.WriteRow(dataReader);
                 return currentFileOffset;
             }