Context url for expand (#1286)

* Set the selectionType to EntireSubtree when the selected list contains only expand tokens.

* For $expand, add navProp() to context-url.

* ABNF v4; ensure explicit select; don't add link for expand to select items.

* Resolve CR comments.
- cleanups
- Create SelectedPropertiesnode based on AllSelected values of current level and expanded nav properties.

* Update for navProp token resolution logic per CR comments; cleanups

src/Microsoft.OData.Core/JsonLight/ODataJsonLightReader.cs

@@ -809,7 +809,7 @@ private bool ReadAtStartImplementationSynchronously(
                 ? null
                 : this.jsonLightResourceDeserializer.ContextUriParseResult.SelectQueryOption;
 
-            SelectedPropertiesNode selectedProperties = SelectedPropertiesNode.Create(selectQueryOption);
+            SelectedPropertiesNode selectedProperties = SelectedPropertiesNode.Create(selectQueryOption, this.CurrentResourceType, this.jsonLightInputContext.Model);
 
             if (this.ReadingResourceSet)
             {
@@ -1493,7 +1493,7 @@ private void ReadNextResourceSetItem()
                     break;
                 case JsonNodeType.StartArray:
                     // we are at the start of a nested resource set
-                    this.ReadResourceSetStart(new ODataResourceSet(), SelectedPropertiesNode.EntireSubtree);
+                    this.ReadResourceSetStart(new ODataResourceSet(), new SelectedPropertiesNode(SelectedPropertiesNode.SelectionType.EntireSubtree));
                     break;
                 case JsonNodeType.EndArray:
                     // we are at the end of a resource set
@@ -1925,7 +1925,7 @@ private void ReadNextNestedResourceInfoContentItemInRequest()
                 if (nestedResourceInfo.NestedResourceInfo.IsCollection == true)
                 {
                     // because this is a request, there is no $select query option.
-                    SelectedPropertiesNode selectedProperties = SelectedPropertiesNode.EntireSubtree;
+                    SelectedPropertiesNode selectedProperties = new SelectedPropertiesNode(SelectedPropertiesNode.SelectionType.EntireSubtree);
                     ODataDeltaResourceSet deltaResourceSet = nestedResourceInfo.NestedResourceSet as ODataDeltaResourceSet;
                     if (deltaResourceSet != null)
                     {

src/Microsoft.OData.Core/ODataContextUrlInfo.cs

@@ -287,7 +287,7 @@ private static string ComputeQueryClause(ODataUri odataUri, ODataVersion version
                 }
                 else
                 {
-                    return CreateSelectExpandContextUriSegment(odataUri.SelectAndExpand, version);
+                    return CreateSelectExpandContextUriSegment(odataUri.SelectAndExpand);
                 }
             }
 
@@ -379,14 +379,13 @@ private static string CreateApplyUriSegment(ApplyClause applyClause)
         /// Build the expand clause for a given level in the selectExpandClause
         /// </summary>
         /// <param name="selectExpandClause">the current level select expand clause</param>
-        /// <param name="version">OData Version of the response</param>
         /// <returns>the select and expand segment for context url in this level.</returns>
-        private static string CreateSelectExpandContextUriSegment(SelectExpandClause selectExpandClause, ODataVersion version)
+        private static string CreateSelectExpandContextUriSegment(SelectExpandClause selectExpandClause)
         {
             if (selectExpandClause != null)
             {
                 string contextUri;
-                selectExpandClause.Traverse(ProcessSubExpand, CombineSelectAndExpandResult, version, out contextUri);
+                selectExpandClause.Traverse(ProcessSubExpand, CombineSelectAndExpandResult, out contextUri);
                 if (!string.IsNullOrEmpty(contextUri))
                 {
                     return ODataConstants.ContextUriProjectionStart + contextUri + ODataConstants.ContextUriProjectionEnd;
@@ -399,12 +398,11 @@ private static string CreateSelectExpandContextUriSegment(SelectExpandClause sel
         /// <summary>Process sub expand node, contact with subexpand result</summary>
         /// <param name="expandNode">The current expanded node.</param>
         /// <param name="subExpand">Generated sub expand node.</param>
-        /// <param name="version">OData Version of the generated response.</param>
         /// <returns>The generated expand string.</returns>
-        private static string ProcessSubExpand(string expandNode, string subExpand, ODataVersion version)
+        private static string ProcessSubExpand(string expandNode, string subExpand)
         {
-            return string.IsNullOrEmpty(subExpand) && version <= ODataVersion.V4 ? null :
-                expandNode + ODataConstants.ContextUriProjectionStart + subExpand + ODataConstants.ContextUriProjectionEnd;
+
+            return expandNode + ODataConstants.ContextUriProjectionStart + subExpand + ODataConstants.ContextUriProjectionEnd;
         }
 
         /// <summary>Create combined result string using selected items list and expand items list.</summary>
@@ -417,15 +415,6 @@ private static string CombineSelectAndExpandResult(IList<string> selectList, ILi
 
             if (selectList.Any())
             {
-                // https://github.com/OData/odata.net/issues/1104
-                // If the user explicitly selects and expands a nav prop, we should include both forms in contextUrl
-                // We can't, though, because SelectExpandClauseFinisher.AddExplicitNavPropLinksWhereNecessary adds all of
-                // the expanded items to the select before it gets here, so we can't tell what is explicitly selected by the user.
-                foreach (var item in expandList)
-                {
-                    string expandNode = item.Substring(0, item.IndexOf(ODataConstants.ContextUriProjectionStart));
-                    selectList.Remove(expandNode);
-                }
 
                 currentExpandClause += String.Join(ODataConstants.ContextUriProjectionPropertySeparator, selectList.ToArray());
             }

src/Microsoft.OData.Core/ODataMessageWriterSettings.cs

@@ -283,8 +283,8 @@ internal SelectedPropertiesNode SelectedProperties
             get
             {
                 return this.SelectExpandClause != null
-                    ? SelectedPropertiesNode.Create(this.SelectExpandClause, this.Version ?? ODataVersion.V4)
-                    : SelectedPropertiesNode.EntireSubtree;
+                    ? SelectedPropertiesNode.Create(this.SelectExpandClause)
+                    : new SelectedPropertiesNode(SelectedPropertiesNode.SelectionType.EntireSubtree);
             }
         }