Use deterministic SHA-256 based documentId generation

Agent-Logs-Url: https://github.com/fsprojects/FSharp.Data.GraphQL/sessions/020d0296-28b1-416d-bd12-9dd0790516ba

Co-authored-by: xperiandri <2365592+xperiandri@users.noreply.github.com>

Author: Copilot

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

@@ -1,14 +1,19 @@
 namespace FSharp.Data.GraphQL
 
+open System
 open System.Collections.Concurrent
 open System.Collections.Immutable
+open System.Buffers.Binary
+open System.Security.Cryptography
 open System.Runtime.InteropServices
+open System.Text
 open System.Text.Json
 open FsToolkit.ErrorHandling
 
 open FSharp.Data.GraphQL.Types
 open FSharp.Data.GraphQL.Execution
 open FSharp.Data.GraphQL.Ast
+open FSharp.Data.GraphQL.Ast.Extensions
 open FSharp.Data.GraphQL.Validation
 open FSharp.Data.GraphQL.Parser
 open FSharp.Data.GraphQL.Planning
@@ -77,6 +82,12 @@ type Executor<'Root>(schema: ISchema<'Root>, middlewares : IExecutorMiddleware s
 
     let middlewaresList = Seq.toList middlewares
 
+    let getDocumentId (document : Document) =
+        let canonicalQuery = document.ToQueryString()
+        let queryBytes = Encoding.UTF8.GetBytes canonicalQuery
+        let hash = SHA256.HashData queryBytes
+        BinaryPrimitives.ReadInt32BigEndian(ReadOnlySpan<byte>(hash, 0, 4))
+
     let rec runMiddlewares (phaseSel : IExecutorMiddleware -> ('ctx -> ('ctx -> 'res) -> 'res) option)
                            (initialCtx : 'ctx)
                            (onComplete : 'ctx -> 'res)
@@ -137,7 +148,7 @@ type Executor<'Root>(schema: ISchema<'Root>, middlewares : IExecutorMiddleware s
         eval (executionPlan, data, variables, getInputContext)
 
     let createExecutionPlan (ast: Document, operationName: string option, meta : Metadata) =
-        let documentId = ast.GetHashCode()
+        let documentId = getDocumentId ast
         result {
             match findOperation ast operationName with
             | Some operation ->

tests/FSharp.Data.GraphQL.Tests/ExecutionTests.fs

@@ -5,6 +5,9 @@ module FSharp.Data.GraphQL.Tests.ExecutionTests
 
 open Xunit
 open System
+open System.Buffers.Binary
+open System.Security.Cryptography
+open System.Text
 open System.Text.Json
 open System.Text.Json.Serialization
 open System.Collections.Immutable
@@ -17,6 +20,7 @@ open FSharp.Data.GraphQL.Shared
 open FSharp.Data.GraphQL.Types
 open FSharp.Data.GraphQL.Parser
 open FSharp.Data.GraphQL.Execution
+open FSharp.Data.GraphQL.Ast.Extensions
 
 type TestSubject = {
     a: string
@@ -383,9 +387,17 @@ let ``Execution when querying returns unique document id with response`` () =
                     Define.Field("a", StringType, fun _ x -> x.A)
                     Define.Field("b", IntType, fun _ x -> x.B)
                 ]))
-    let result1 = sync <| Executor(schema).AsyncExecute("query Example { a, b, a }", getMockInputContext, { A = "aa"; B = 2 })
-    let result2 = sync <| Executor(schema).AsyncExecute("query Example { a, b, a }", getMockInputContext, { A = "aa"; B = 2 })
+    let query = "query Example { a, b, a }"
+    let expectedDocumentId =
+        let canonicalQuery =
+            let ast = parse query
+            ast.ToQueryString()
+        let hash = SHA256.HashData(Encoding.UTF8.GetBytes canonicalQuery)
+        BinaryPrimitives.ReadInt32BigEndian(ReadOnlySpan<byte>(hash, 0, 4))
+    let result1 = sync <| Executor(schema).AsyncExecute(query, getMockInputContext, { A = "aa"; B = 2 })
+    let result2 = sync <| Executor(schema).AsyncExecute(query, getMockInputContext, { A = "aa"; B = 2 })
     result1.DocumentId |> notEquals Unchecked.defaultof<int>
+    result1.DocumentId |> equals expectedDocumentId
     result1.DocumentId |> equals result2.DocumentId
     match result1,result2 with
     | Direct(data1, errors1), Direct(data2, errors2) ->