From 1707d31bab68a3f291812f157c133ee73b8e2f0c Mon Sep 17 00:00:00 2001
From: Guillaume Hivert <hivert.is.coming@gmail.com>
Date: Tue, 17 Sep 2024 18:35:26 +0200
Subject: [PATCH] Fix correct signature for `cache` on Erlang target

---
 sketch/src/sketch/error.gleam                 | 4 ++++
 sketch/src/sketch/internals/cache/setup.gleam | 9 ++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/sketch/src/sketch/error.gleam b/sketch/src/sketch/error.gleam
index ccb3588..d03f8e6 100644
--- a/sketch/src/sketch/error.gleam
+++ b/sketch/src/sketch/error.gleam
@@ -1,5 +1,9 @@
 //// Defines standard error returned by sketch.
 
+import gleam/otp/actor
+
+/// NotABrowser is unused nowadays. It will be removed in v4.
 pub type SketchError {
   NotABrowser
+  OtpError(actor.StartError)
 }
diff --git a/sketch/src/sketch/internals/cache/setup.gleam b/sketch/src/sketch/internals/cache/setup.gleam
index d9bf217..1344d29 100644
--- a/sketch/src/sketch/internals/cache/setup.gleam
+++ b/sketch/src/sketch/internals/cache/setup.gleam
@@ -6,6 +6,7 @@ import gleam/list
 import gleam/otp/actor
 import gleam/pair
 import gleam/result
+import sketch/error.{type SketchError}
 import sketch/internals/cache/state
 import sketch/internals/style
 
@@ -21,9 +22,11 @@ pub fn ephemeral() {
 }
 
 @target(erlang)
-pub fn persistent() -> Result(Cache, Nil) {
-  let assert Ok(subject) = actor.start(style.persistent(), state.loop)
-  Ok(PersistentCache(subject))
+pub fn persistent() -> Result(Cache, SketchError) {
+  let subject = actor.start(style.persistent(), state.loop)
+  subject
+  |> result.map(PersistentCache)
+  |> result.map_error(error.OtpError)
 }
 
 @target(erlang)