From 931511b8902dc72ac233c12326ea35d621212988 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Wed, 14 Jan 2026 10:29:52 +0100
Subject: [PATCH] Refactor Result

---
 packages/effect-fc/src/Result.ts | 35 +++++++++-----------------------
 1 file changed, 10 insertions(+), 25 deletions(-)

diff --git a/packages/effect-fc/src/Result.ts b/packages/effect-fc/src/Result.ts
index a8a72ca..c0275c9 100644
--- a/packages/effect-fc/src/Result.ts
+++ b/packages/effect-fc/src/Result.ts
@@ -1,4 +1,4 @@
-import { Cause, Context, Data, Effect, Equal, Exit, type Fiber, Hash, Layer, Match, Option, Pipeable, Predicate, PubSub, pipe, Ref, type Scope, Stream, Subscribable } from "effect"
+import { Cause, Context, Data, Effect, Equal, Exit, type Fiber, Hash, Layer, Match, Pipeable, Predicate, PubSub, pipe, Ref, type Scope, Stream, Subscribable } from "effect"
 
 
 export const ResultTypeId: unique symbol = Symbol.for("@effect-fc/Result/Result")
@@ -12,7 +12,7 @@ export type Result<A, E = never, P = never> = (
 )
 
 // biome-ignore lint/complexity/noBannedTypes: "{}" is relevant here
-export type Final<A, E = never, P = never> = (Success<A> | Failure<A, E>) & ({} | Flags<P>)
+export type Final<A, E = never, P = never> = (Success<A> | Failure<E>) & ({} | Flags<P>)
 export type Flags<P = never> = WillFetch | WillRefresh | Refreshing<P>
 
 export declare namespace Result {
@@ -43,10 +43,9 @@ export interface Success<A> extends Result.Prototype {
     readonly value: A
 }
 
-export interface Failure<A, E = never> extends Result.Prototype {
+export interface Failure<E = never> extends Result.Prototype {
     readonly _tag: "Failure"
     readonly cause: Cause.Cause<E>
-    readonly previousSuccess: Option.Option<Success<A>>
 }
 
 export interface WillFetch {
@@ -76,7 +75,7 @@ const ResultPrototype = Object.freeze({
             Match.tag("Initial", () => true),
             Match.tag("Running", self => Equal.equals(self.progress, (that as Running<any>).progress)),
             Match.tag("Success", self => Equal.equals(self.value, (that as Success<any>).value)),
-            Match.tag("Failure", self => Equal.equals(self.cause, (that as Failure<any, any>).cause)),
+            Match.tag("Failure", self => Equal.equals(self.cause, (that as Failure<any>).cause)),
             Match.exhaustive,
         )
     },
@@ -105,7 +104,7 @@ export const isFinal = (u: unknown): u is Final<unknown, unknown, unknown> => is
 export const isInitial = (u: unknown): u is Initial => isResult(u) && u._tag === "Initial"
 export const isRunning = (u: unknown): u is Running<unknown> => isResult(u) && u._tag === "Running"
 export const isSuccess = (u: unknown): u is Success<unknown> => isResult(u) && u._tag === "Success"
-export const isFailure = (u: unknown): u is Failure<unknown, unknown> => isResult(u) && u._tag === "Failure"
+export const isFailure = (u: unknown): u is Failure<unknown> => isResult(u) && u._tag === "Failure"
 export const hasFlag = (u: unknown): u is Flags => isResult(u) && Predicate.hasProperty(u, "_flag")
 export const hasWillFetchFlag = (u: unknown): u is WillFetch => isResult(u) && Predicate.hasProperty(u, "_flag") && u._flag === "WillFetch"
 export const hasWillRefreshFlag = (u: unknown): u is WillRefresh => isResult(u) && Predicate.hasProperty(u, "_flag") && u._flag === "WillRefresh"
@@ -117,15 +116,7 @@ export const initial: {
 } = (): Initial => Object.setPrototypeOf({ _tag: "Initial" }, ResultPrototype)
 export const running = <P = never>(progress?: P): Running<P> => Object.setPrototypeOf({ _tag: "Running", progress }, ResultPrototype)
 export const succeed = <A>(value: A): Success<A> => Object.setPrototypeOf({ _tag: "Success", value }, ResultPrototype)
-
-export const fail = <E, A = never>(
-    cause: Cause.Cause<E>,
-    previousSuccess?: Success<NoInfer<A>>,
-): Failure<A, E> => Object.setPrototypeOf({
-    _tag: "Failure",
-    cause,
-    previousSuccess: Option.fromNullable(previousSuccess),
-}, ResultPrototype)
+export const fail = <E>(cause: Cause.Cause<E> ): Failure<E> => Object.setPrototypeOf({ _tag: "Failure", cause }, ResultPrototype)
 
 export const willFetch = <R extends Initial | Final<any, any, any>>(
     result: R
@@ -150,11 +141,8 @@ export const refreshing = <R extends Final<any, any, any>, P = never>(
 )
 
 export const fromExit = <A, E>(
-    exit: Exit.Exit<A, E>,
-    previousSuccess?: Success<NoInfer<A>>,
-): Success<A> | Failure<A, E> => exit._tag === "Success"
-    ? succeed(exit.value)
-    : fail(exit.cause, previousSuccess)
+    exit: Exit.Exit<A, E>
+): Success<A> | Failure<E> => exit._tag === "Success" ? succeed(exit.value) : fail(exit.cause)
 
 export const toExit = <A, E, P>(
     self: Result<A, E, P>
@@ -219,7 +207,7 @@ export namespace unsafeForkEffect {
 
     export interface Options<A, E, P> {
         // biome-ignore lint/complexity/noBannedTypes: "{}" is relevant here
-        readonly initial?: (Initial | Success<A> | Failure<A, E>) & ({} | WillFetch | WillRefresh)
+        readonly initial?: (Initial | Success<A> | Failure<E>) & ({} | WillFetch | WillRefresh)
         readonly initialProgress?: P
     }
 }
@@ -242,10 +230,7 @@ export const unsafeForkEffect = <A, E, R, P = never>(
         ).pipe(
             Effect.andThen(effect),
             Effect.onExit(exit => Effect.andThen(
-                state.set(fromExit(
-                    exit,
-                    isSuccess(options?.initial) ? options.initial : undefined),
-                ),
+                state.set(fromExit(exit)),
                 Effect.forkScoped(PubSub.shutdown(pubsub)),
             )),
         )),