Build each Operation<...> instantiation of the client provider once (#620)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: xperiandri

RELEASE_NOTES.md

@@ -324,4 +324,5 @@
 * Fixed `graphql-transport-ws` sending a request error (rejected before execution: validation, planning, variable coercion, a middleware, or the executor itself failing) as a `next` result followed by `complete`, instead of the terminal `error` message the protocol requires for it; a query or mutation whose non-null root field fails during execution still gets `next` + `complete`, since it is a result, not a request error
 * Fixed `graphql-transport-ws` throwing while serializing an `error` message or a `pong` carrying a payload, since neither was written under the `payload` property name `Utf8JsonWriter` requires
 * Fixed validation of an inline fragment without a type condition (`... { … }`), which used to fail with an exception instead of applying to the parent type
+* Fixed the GraphQL client provider building `Operation<...>` again for every file that uses the same operation, which added another operation type of the same name to `Operations` each time
 * Removed the internal `Observable.withCompletionMarker`

src/FSharp.Data.GraphQL.Client.DesignTime/ProvidedTypesHelper.fs

@@ -937,7 +937,20 @@ module internal Provider =
                                 operationWrapper.AddMember(operationDef)
                                 operationDef.AddMember(methodDef)
                                 methodDef
-                            staticMethodDef.DefineStaticParameters(staticParams, instanceBuilder)
+                            // The compiler applies the same static arguments again for every file that uses an operation,
+                            // and each instantiation adds its operation type to Operations. A second type of the same name
+                            // makes the two incompatible (FS0193), so every instantiation is built once and then reused.
+                            // The lock also keeps the instantiations from adding members to Operations concurrently.
+                            let instances = Dictionary<string, ProvidedMethod>(StringComparer.Ordinal)
+                            let getOrBuildInstance (methodName : string) (args : obj []) =
+                                lock instances (fun () ->
+                                    match instances.TryGetValue(methodName) with
+                                    | true, instance -> instance
+                                    | false, _ ->
+                                        let instance = instanceBuilder methodName args
+                                        instances.Add(methodName, instance)
+                                        instance)
+                            staticMethodDef.DefineStaticParameters(staticParams, getOrBuildInstance)
                             staticMethodDef
                         let schemaPropertyDef =
                             let getter = QuotationHelpers.quoteRecord schema (fun (_ : Expr list) schema -> schema)