From 7fa5f54f88b1346fd33e45bca2fda95e20ef8ace Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Mon, 18 May 2026 14:32:26 +0200
Subject: [PATCH] Fix provide

---
 packages/effect-lens/src/Lens.ts | 43 +++++++++++++++++++++++++-------
 1 file changed, 34 insertions(+), 9 deletions(-)

diff --git a/packages/effect-lens/src/Lens.ts b/packages/effect-lens/src/Lens.ts
index 7ad71fe..491235d 100644
--- a/packages/effect-lens/src/Lens.ts
+++ b/packages/effect-lens/src/Lens.ts
@@ -1,4 +1,4 @@
-import { Array, Chunk, Effect, Function, identity, type Layer, Option, Pipeable, Predicate, Readable, Stream, type Context, type SubscriptionRef, type SynchronizedRef } from "effect"
+import { Array, Chunk, type Context, Effect, Function, identity, type Layer, type ManagedRuntime, Option, Pipeable, Predicate, Readable, type Runtime, Stream, type SubscriptionRef, type SynchronizedRef } from "effect"
 import type { NoSuchElementException } from "effect/Cause"
 import * as Subscribable from "./Subscribable.js"
 
@@ -270,7 +270,12 @@ export const mapStream: {
 }))
 
 /**
- * Provides a single service to a `Lens`, removing it from both the read and write environments.
+ * Provides the requirements of a `Lens`, removing them from both the read and write environments.
+ *
+ * Accepts the same provider forms as `Effect.provide`: one or more `Layer`s, a `Context`,
+ * a `Runtime`, or a `ManagedRuntime`.
+ *
+ * Layer providers may add their construction errors to both the read and write error channels.
  */
 export const provide: {
     <const Layers extends readonly [Layer.Layer.Any, ...Array<Layer.Layer.Any>]>(
@@ -288,6 +293,12 @@ export const provide: {
     <R2>(
         context: Context.Context<R2>,
     ): <A, ER, EW, RR, RW>(self: Lens<A, ER, EW, RR, RW>) => Lens<A, ER, EW, Exclude<RR, R2>, Exclude<RW, R2>>
+    <R2>(
+        runtime: Runtime.Runtime<R2>,
+    ): <A, ER, EW, RR, RW>(self: Lens<A, ER, EW, RR, RW>) => Lens<A, ER, EW, Exclude<RR, R2>, Exclude<RW, R2>>
+    <E2, R2>(
+        managedRuntime: ManagedRuntime.ManagedRuntime<R2, E2>,
+    ): <A, ER, EW, RR, RW>(self: Lens<A, ER, EW, RR, RW>) => Lens<A, ER | E2, EW | E2, Exclude<RR, R2>, Exclude<RW, R2>>
     <A, ER, EW, RR, RW, const Layers extends readonly [Layer.Layer.Any, ...Array<Layer.Layer.Any>]>(
         self: Lens<A, ER, EW, RR, RW>,
         layers: Layers,
@@ -306,24 +317,38 @@ export const provide: {
         self: Lens<A, ER, EW, RR, RW>,
         context: Context.Context<R2>,
     ): Lens<A, ER, EW, Exclude<RR, R2>, Exclude<RW, R2>>
-} = Function.dual(2, <A, ER, EW, RR, RW>(
+    <A, ER, EW, RR, RW, R2>(
+        self: Lens<A, ER, EW, RR, RW>,
+        runtime: Runtime.Runtime<R2>,
+    ): Lens<A, ER, EW, Exclude<RR, R2>, Exclude<RW, R2>>
+    <A, ER, EW, RR, RW, E2, R2>(
+        self: Lens<A, ER, EW, RR, RW>,
+        runtime: ManagedRuntime.ManagedRuntime<R2, E2>,
+    ): Lens<A, ER | E2, EW | E2, Exclude<RR, R2>, Exclude<RW, R2>>
+} = Function.dual(2, <A, ER, EW, RR, RW, ROut, E2, RIn>(
     self: Lens<A, ER, EW, RR, RW>,
-    provider: unknown,
-): Lens<A, any, any, any, any> => make({
-    get get() { return Effect.provide(self.get, provider as any) },
+    layer: Layer.Layer<ROut, E2, RIn>,
+): Lens<A, ER | E2, EW | E2, RIn | Exclude<RR, ROut>, RIn | Exclude<RW, ROut>> => make({
+    get get() { return Effect.provide(self.get, layer) },
     get changes() {
         return Stream.unwrapScoped(
             Effect.map(
-                Effect.provide(Effect.context<RR>(), provider as any),
-                (context) => Stream.provideContext(self.changes as Stream.Stream<A, ER, RR>, context),
+                Effect.provide(Effect.context<RR>(), layer),
+                context => Stream.provideContext(self.changes, context),
             ),
         )
     },
     modify: <B, E1 = never, R1 = never>(
         f: (a: A) => Effect.Effect<readonly [B, A], E1, R1>
-    ) => Effect.provide(self.modify(f), provider as any),
+    ) => Effect.provide(self.modify(f), layer),
 }))
 
+/**
+ * Provides a single service to a `Lens`, removing it from both the read and write environments.
+ *
+ * This is the `Lens` equivalent of `Effect.provideService`: use it when a lens requires one
+ * `Context.Tag` and you already have the concrete service value.
+ */
 export const provideService: {
     <A, ER, EW, RR, RW, I, S>(
         self: Lens<A, ER, EW, RR, RW>,