Merged PR 426996: Revert "Context url for expand (OData#1286)"

Revert "Context url for expand (OData#1286)"

This reverts commit ec6fb33.

Original PR not only modified how @odata.context formed for v4.0 and v4.01, but also removed a lot of version recognition code. That makes it’s pretty difficult to do conditionally.

Please, keep in mind that default protocol version is v4.0 and client had to say that it wants v4.01. In AX I'm going to add telemetry to allow us to see what clients asked for

Related work items: #1426955

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

@@ -809,7 +809,7 @@ private bool ReadAtStartImplementationSynchronously(
                 ? null
                 : this.jsonLightResourceDeserializer.ContextUriParseResult.SelectQueryOption;
 
-            SelectedPropertiesNode selectedProperties = SelectedPropertiesNode.Create(selectQueryOption, this.CurrentResourceType, this.jsonLightInputContext.Model);
+            SelectedPropertiesNode selectedProperties = SelectedPropertiesNode.Create(selectQueryOption);
 
             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(), new SelectedPropertiesNode(SelectedPropertiesNode.SelectionType.EntireSubtree));
+                    this.ReadResourceSetStart(new ODataResourceSet(), SelectedPropertiesNode.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 = new SelectedPropertiesNode(SelectedPropertiesNode.SelectionType.EntireSubtree);
+                    SelectedPropertiesNode selectedProperties = SelectedPropertiesNode.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);
+                    return CreateSelectExpandContextUriSegment(odataUri.SelectAndExpand, version);
                 }
             }
 
@@ -379,13 +379,14 @@ 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)
+        private static string CreateSelectExpandContextUriSegment(SelectExpandClause selectExpandClause, ODataVersion version)
         {
             if (selectExpandClause != null)
             {
                 string contextUri;
-                selectExpandClause.Traverse(ProcessSubExpand, CombineSelectAndExpandResult, out contextUri);
+                selectExpandClause.Traverse(ProcessSubExpand, CombineSelectAndExpandResult, version, out contextUri);
                 if (!string.IsNullOrEmpty(contextUri))
                 {
                     return ODataConstants.ContextUriProjectionStart + contextUri + ODataConstants.ContextUriProjectionEnd;
@@ -398,11 +399,12 @@ 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)
+        private static string ProcessSubExpand(string expandNode, string subExpand, ODataVersion version)
         {
-
-            return expandNode + ODataConstants.ContextUriProjectionStart + subExpand + ODataConstants.ContextUriProjectionEnd;
+            return string.IsNullOrEmpty(subExpand) && version <= ODataVersion.V4 ? null :
+                expandNode + ODataConstants.ContextUriProjectionStart + subExpand + ODataConstants.ContextUriProjectionEnd;
         }
 
         /// <summary>Create combined result string using selected items list and expand items list.</summary>
@@ -415,6 +417,15 @@ 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

@@ -292,8 +292,8 @@ internal SelectedPropertiesNode SelectedProperties
             get
             {
                 return this.SelectExpandClause != null
-                    ? SelectedPropertiesNode.Create(this.SelectExpandClause)
-                    : new SelectedPropertiesNode(SelectedPropertiesNode.SelectionType.EntireSubtree);
+                    ? SelectedPropertiesNode.Create(this.SelectExpandClause, this.Version ?? ODataVersion.V4)
+                    : SelectedPropertiesNode.EntireSubtree;
             }
         }