Implemented support for optional properties usage in non-Enumerable LINQ queries (#529)

* Implemented support for optional properties usage in non-Enumerable LINQ queries
* Implemented tests for queries translation to Azure Cosmos DB

---------

Co-authored-by: Viktor Tochonov <[email protected]>
Co-authored-by: Andrii Chebukin <[email protected]>

Author: 3 people

src/FSharp.Data.GraphQL.Server.AspNetCore/Helpers.fs

@@ -43,7 +43,9 @@ module ReflectionHelpers =
 
     open Microsoft.FSharp.Quotations.Patterns
 
-    let getModuleType = function
+    let getModuleType quotation =
+        match quotation with
         | PropertyGet (_, propertyInfo, _) -> propertyInfo.DeclaringType
+        | FieldGet (_, fieldInfo) -> fieldInfo.DeclaringType
         | _ -> failwith "Expression is no property."
 

src/FSharp.Data.GraphQL.Server.Middleware/ObjectListFilter.fs

@@ -116,7 +116,7 @@ let rec private coerceObjectListFilterInput x : Result<ObjectListFilter voption,
             let! parsedValues =
                 values
                 |> Seq.map (function
-                    | EquatableValue v -> Ok v
+                    | EquatableValue v -> Ok (box v)
                     | NonEquatableValue v ->
                         Error
                             { new IGQLError with

src/FSharp.Data.GraphQL.Server.Middleware/SchemaDefinitions.fs

@@ -26,6 +26,9 @@
     <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleToAttribute">
       <_Parameter1>FSharp.Data.GraphQL.Server.AspNetCore</_Parameter1>
     </AssemblyAttribute>
+    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleToAttribute">
+      <_Parameter1>FSharp.Data.GraphQL.Server.Middleware</_Parameter1>
+    </AssemblyAttribute>
   </ItemGroup>
 
   <ItemGroup>

src/FSharp.Data.GraphQL.Server/FSharp.Data.GraphQL.Server.fsproj

@@ -30,7 +30,7 @@ let private wrapOptionalNone (outputType : Type) (inputType : Type) =
     else
         null
 
-let private normalizeOptional (outputType : Type) value =
+let normalizeOptional (outputType : Type) value =
     match value with
     | null -> wrapOptionalNone outputType typeof<obj>
     | value ->

src/FSharp.Data.GraphQL.Server/Values.fs

@@ -38,6 +38,27 @@ module internal Seq =
         |> Seq.map ValueSome
         |> _.FirstOrDefault()
 
+    let vtryHead (source : 'T seq) =
+        use enumerator = source.GetEnumerator ()
+        if not (enumerator.MoveNext ()) then
+            ValueNone
+        else
+            match enumerator.Current with
+            | null -> ValueNone
+            | head -> ValueSome head
+
+    let vtryLast (source : 'T seq) =
+        use enumerator = source.GetEnumerator ()
+        if not (enumerator.MoveNext ()) then
+            ValueNone
+        else
+            let mutable last = enumerator.Current
+            while enumerator.MoveNext () do
+                last <- enumerator.Current
+            match last with
+            | null -> ValueNone
+            | last -> ValueSome last
+
 module internal List =
 
     let vchoose mapping list = list |> Seq.ofList |> Seq.vchoose mapping |> List.ofSeq

src/FSharp.Data.GraphQL.Shared/Helpers/ObjAndStructConversions.fs

@@ -10,43 +10,28 @@ open System.Reflection
 open System.Text.Json.Serialization
 
 /// General helper functions and types.
-module Helpers =
+module internal ReflectionHelper =
 
-    /// Casts a System.Object to a System.Object option.
-    let optionCast (value: obj) =
-        if isNull value then None
-        else
-            let t = value.GetType()
-            if t.FullName.StartsWith  "Microsoft.FSharp.Core.FSharpOption`1" then
-                let p = t.GetProperty("Value")
-                Some (p.GetValue(value, [||]))
-            elif t.FullName.StartsWith "Microsoft.FSharp.Core.FSharpValueOption`1" then
-                if value = Activator.CreateInstance t then None
-                else
-                    let p = t.GetProperty("Value")
-                    Some (p.GetValue(value, [||]))
-            else None
+    open Microsoft.FSharp.Quotations.Patterns
 
-    /// Matches a System.Object with an option.
-    /// If the object is an Option, returns it as Some, otherwise, return None.
-    let (|ObjectOption|_|) = optionCast
+    let getModuleType quotation =
+        match quotation with
+        | PropertyGet (_, propertyInfo, _) -> propertyInfo.DeclaringType
+        | FieldGet (_, fieldInfo) -> fieldInfo.DeclaringType
+        | _ -> failwith "Expression is no property."
 
-    /// Lifts a System.Object to an option, unless it is already an option.
-    let toOption x =
-        match x with
-        | null -> None
-        | ObjectOption v
-        | v -> Some v
-
-module internal ReflectionHelper =
+    let [<Literal>] OptionTypeName = "Microsoft.FSharp.Core.FSharpOption`1"
+    let [<Literal>] ValueOptionTypeName = "Microsoft.FSharp.Core.FSharpValueOption`1"
+    let [<Literal>] SkippableTypeName = "System.Text.Json.Serialization.Skippable`1"
 
+    let private listGenericTypeInfo = typedefof<_ list>.GetTypeInfo()
     /// <summary>
     /// Returns pair of function constructors for `cons(head,tail)` and `nil`
     /// used to create list of type <paramref name="t"/> given at runtime.
     /// </summary>
     /// <param name="t">Type used for result list constructors as type param</param>
     let listOfType t =
-        let listType = typedefof<_ list>.GetTypeInfo().MakeGenericType([|t|]).GetTypeInfo()
+        let listType = listGenericTypeInfo.MakeGenericType([|t|]).GetTypeInfo()
         let nil =
             let empty = listType.GetDeclaredProperty "Empty"
             empty.GetValue (null)
@@ -67,13 +52,14 @@ module internal ReflectionHelper =
         )
         array :> obj
 
+    let private optionGenericTypeInfo = typedefof<_ option>.GetTypeInfo()
     /// <summary>
     /// Returns pair of function constructors for `some(value)` and `none`
     /// used to create option of type <paramref name="t"/> given at runtime.
     /// </summary>
     /// <param name="t">Type used for result option constructors as type param</param>
     let optionOfType t =
-        let optionType = typedefof<_ option>.GetTypeInfo().MakeGenericType([|t|]).GetTypeInfo()
+        let optionType = optionGenericTypeInfo.MakeGenericType([|t|]).GetTypeInfo()
         let none =
             let x = optionType.GetDeclaredProperty "None"
             x.GetValue(null)
@@ -101,13 +87,14 @@ module internal ReflectionHelper =
                 else input
         (some, none, value)
 
+    let private valueOptionGenericTypeInfo = typedefof<_ voption>.GetTypeInfo()
     /// <summary>
     /// Returns pair of function constructors for `some(value)` and `none`
     /// used to create option of type <paramref name="t"/> given at runtime.
     /// </summary>
     /// <param name="t">Type used for result option constructors as type param</param>
     let vOptionOfType t =
-        let optionType = typedefof<_ voption>.GetTypeInfo().MakeGenericType([|t|]).GetTypeInfo()
+        let optionType = valueOptionGenericTypeInfo.MakeGenericType([|t|]).GetTypeInfo()
         let none =
             let x = optionType.GetDeclaredProperty "None"
             x.GetValue(null)
@@ -157,13 +144,14 @@ module internal ReflectionHelper =
                 else createInclude.Invoke(null, [| value |])
         (``include``, skip)
 
+    let skippableGenericTypeInfo = typedefof<_ Skippable>.GetTypeInfo()
     /// <summary>
     /// Returns pair of function constructors for `include(value)` and `skip`
     /// used to create option of type <paramref name="t"/> given at runtime.
     /// </summary>
     /// <param name="t">Type used for result option constructors as type param</param>
     let skippableOfType t =
-        let skippableType = typedefof<_ Skippable>.GetTypeInfo().MakeGenericType([|t|]).GetTypeInfo()
+        let skippableType = skippableGenericTypeInfo.MakeGenericType([|t|]).GetTypeInfo()
         let skip =
             let x = skippableType.GetDeclaredProperty "Skip"
             x.GetValue(null)
@@ -178,3 +166,56 @@ module internal ReflectionHelper =
                 then value
                 else createInclude.Invoke(null, [| value |])
         (``include``, skip)
+
+module Helpers =
+
+    let rec internal moduleType = ReflectionHelper.getModuleType <@ moduleType @>
+
+    /// <summary>
+    /// Casts a <see cref="System.Object"/> to a <see cref="option{System.Object}"/>.
+    /// </summary>
+    let optionCast (value: obj) =
+        if isNull value then None
+        else
+            let t = value.GetType()
+            if t.FullName.StartsWith ReflectionHelper.OptionTypeName then
+                let p = t.GetProperty("Value")
+                Some (p.GetValue(value, [||]))
+            elif t.FullName.StartsWith ReflectionHelper.ValueOptionTypeName then
+                if value = Activator.CreateInstance t then None
+                else
+                    let p = t.GetProperty("Value")
+                    Some (p.GetValue(value, [||]))
+            else None
+
+    /// <summary>
+    /// Matches a System.Object with an option.
+    /// If the object is an <see cref="Option{T}", returns it as Some, otherwise, return <see cref="None"/>.
+    /// </summary>
+    let (|ObjectOption|_|) = optionCast
+
+    /// <summary>
+    /// Lifts a <see cref="System.Object"/> to an <see cref="option{System.Object}"/>, unless it is already an <see cref="option{System.Object}"/>.
+    /// </summary>
+    let toOption x =
+        match x with
+        | null -> None
+        | ObjectOption v
+        | v -> Some v
+
+    /// <summary>
+    /// Unwraps a <see cref="System.Object"/> from an <see cref="option{System.Object}"/> or <see cref="voption{System.Object}"/>,
+    /// unless it is not wrapped.
+    /// </summary>
+    let unwrap (value : objnull) =
+        match value with
+        | null -> null
+        | value ->
+            let t = value.GetType()
+            if t.FullName.StartsWith ReflectionHelper.OptionTypeName then
+                t.GetProperty("Value").GetValue (value, [||])
+            elif t.FullName.StartsWith ReflectionHelper.ValueOptionTypeName then
+                if value = Activator.CreateInstance t then null
+                else
+                    t.GetProperty("Value").GetValue (value, [||])
+            else value