EFF-898 Fix StructuralProto equality

.changeset/fix-structural-proto-equality.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Fix structural equality for request-style values when structural hashes collide.

packages/effect/src/internal/core.ts

@@ -87,7 +87,7 @@ export const StructuralProto = {
     const thatKeys = Object.keys(that)
     if (selfKeys.length !== thatKeys.length) return false
     for (let i = 0; i < selfKeys.length; i++) {
-      if (selfKeys[i] !== thatKeys[i] && !Equal.equals(this[selfKeys[i]], that[selfKeys[i]])) {
+      if (selfKeys[i] !== thatKeys[i] || !Equal.equals(this[selfKeys[i]], that[selfKeys[i]])) {
         return false
       }
     }

packages/effect/test/Request.test.ts

@@ -1,5 +1,5 @@
 import { assert, describe, expect, it } from "@effect/vitest"
-import { Array, Context, Data, Fiber } from "effect"
+import { Array, Context, Data, Equal, Fiber, Hash } from "effect"
 import * as Cause from "effect/Cause"
 import * as Effect from "effect/Effect"
 import * as Exit from "effect/Exit"
@@ -133,6 +133,16 @@ const provideEnv = flow(
 )
 
 describe.sequential("Request", () => {
+  it("compares StructuralProto values when hashes collide", () => {
+    class Req extends Request.Class<{ id: string; account: string }, string> {}
+
+    const a = new Req({ id: "id-8", account: "acct-2811" })
+    const b = new Req({ id: "id-14", account: "acct-755" })
+
+    assert.strictEqual(Hash.hash(a), Hash.hash(b))
+    assert.strictEqual(Equal.equals(a, b), false)
+  })
+
   it.effect(
     "requests are executed correctly",
     Effect.fnUntraced(function*() {