From 04adcace913e6fc483df266874a68005e9e04ccf Mon Sep 17 00:00:00 2001
From: Tim <hello@timsmart.co>
Date: Mon, 12 Aug 2024 12:53:51 +1200
Subject: [PATCH] ensure Stream.toReadableStream pulls always result in a
 enqueue (#3444)

---
 .changeset/soft-cows-beam.md           | 5 +++++
 packages/effect/src/internal/stream.ts | 6 +++++-
 2 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/soft-cows-beam.md

diff --git a/.changeset/soft-cows-beam.md b/.changeset/soft-cows-beam.md
new file mode 100644
index 0000000000..a478d224ba
--- /dev/null
+++ b/.changeset/soft-cows-beam.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+ensure Stream.toReadableStream pulls always result in a enqueue
diff --git a/packages/effect/src/internal/stream.ts b/packages/effect/src/internal/stream.ts
index 9d28dab7f9..459827d6bc 100644
--- a/packages/effect/src/internal/stream.ts
+++ b/packages/effect/src/internal/stream.ts
@@ -6895,10 +6895,14 @@ export const toReadableStreamRuntime = dual<
     return new ReadableStream<A>({
       start(controller) {
         scope = runSync(Scope.make())
-        pull = pipe(
+        const pullChunk: Effect.Effect<Chunk.Chunk<A>, Option.Option<E>, R> = pipe(
           toPull(self),
           Scope.extend(scope),
           runSync,
+          Effect.flatMap((chunk) => Chunk.isEmpty(chunk) ? pullChunk : Effect.succeed(chunk))
+        )
+        pull = pipe(
+          pullChunk,
           Effect.tap((chunk) =>
             Effect.sync(() => {
               Chunk.map(chunk, (a) => {