Fix: Null Handling in NodeKind Intellisense (#2552)

CurNode in IntellisenseData can be Null in different scenarios and we
have a NullNodeIntellisense Handler for this specific reason which
suggests global/ in scope Values , However this may not be applicable to
all the cases such as suggesting types for UDF.

Not handling null here forces us to have a very strict order in running
intellisense handlers , otherwise raising an exception which leads to no
Intellisense results.

It is safe for us to assume CurNode could be null and skip the current
suggestion handler instead of throwing an exception.

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/IntellisenseData/IntellisenseData.cs

@@ -32,8 +32,8 @@ namespace Microsoft.PowerFx.Intellisense.IntellisenseData
         {
             Contracts.AssertValue(context);
             Contracts.AssertValid(expectedType);
-            Contracts.AssertValue(binding);
-            Contracts.AssertValue(curNode);
+            Contracts.AssertValueOrNull(binding);
+            Contracts.AssertValueOrNull(curNode);
             Contracts.Assert(context.CursorPosition >= 0 && context.CursorPosition <= context.InputText.Length);
             Contracts.AssertValue(isValidSuggestionFunc);
             Contracts.AssertValueOrNull(missingTypes);

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/BinaryOpNodeSuggestionHandler.cs

@@ -19,6 +19,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
 

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/BoolLitNodeSuggestionHandler.cs

@@ -19,6 +19,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/CallNodeSuggestionHandler.cs

@@ -18,6 +18,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/DottedNameNodeSuggestionHandler.cs

@@ -25,6 +25,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/ErrorNodeSuggestionHandlerBase.cs

@@ -18,6 +18,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 // For Error Kind, suggest top level values only in the context of a callNode and
                 // ThisItemProperties only in the context of thisItem.

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/FirstNameNodeSuggestionHandler.cs

@@ -21,6 +21,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/NodeKindSuggestionHandler.cs

@@ -24,9 +24,9 @@ namespace Microsoft.PowerFx.Intellisense
             public bool Run(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
-                Contracts.AssertValue(intellisenseData.CurNode);
+                Contracts.AssertValueOrNull(intellisenseData.CurNode);
 
-                if (intellisenseData.CurNode.Kind != _kind)
+                if (intellisenseData.CurNode == null || intellisenseData.CurNode.Kind != _kind)
                 {
                     return false;
                 }

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/RecordNodeSuggestionHandler.cs

@@ -22,6 +22,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/StrInterpSuggestionHandler.cs

@@ -18,6 +18,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/TableNodeSuggestionHandler.cs

@@ -19,6 +19,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/UnaryOpNodeSuggestionHandler.cs

@@ -19,6 +19,7 @@ namespace Microsoft.PowerFx.Intellisense
             internal override bool TryAddSuggestionsForNodeKind(IntellisenseData.IntellisenseData intellisenseData)
             {
                 Contracts.AssertValue(intellisenseData);
+                Contracts.AssertValue(intellisenseData.CurNode);
 
                 var curNode = intellisenseData.CurNode;
                 var cursorPos = intellisenseData.CursorPos;