From 19b534a9e25ba6a84bce819928577c3f84c7d34f Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Wed, 29 Apr 2026 22:14:23 +0000
Subject: [PATCH] fix(nestsClient): register inbound moq-lite subscription
 before sending Ok

The publisher's inbound-bidi handler wrote SubscribeOk to the bidi
before calling registerInboundSubscription. The peer's first
publisher.send() after observing Ok could race the registration on
dispatchers that resume the peer's continuation before the handler's
(notably Windows under Dispatchers.Default), causing send to observe
an empty inboundSubs and return false. Reordering makes the peer's
view of Ok a happens-after of the registration.

Fixes the Windows-only failure in
MoqLiteSessionTest.publisher_acks_subscribe_and_pushes_group_data_on_uni_stream.
---
 .../nestsclient/moq/lite/MoqLiteSession.kt           | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/nestsClient/src/commonMain/kotlin/com/vitorpamplona/nestsclient/moq/lite/MoqLiteSession.kt b/nestsClient/src/commonMain/kotlin/com/vitorpamplona/nestsclient/moq/lite/MoqLiteSession.kt
index 573f94565..94f043bf8 100644
--- a/nestsClient/src/commonMain/kotlin/com/vitorpamplona/nestsclient/moq/lite/MoqLiteSession.kt
+++ b/nestsClient/src/commonMain/kotlin/com/vitorpamplona/nestsclient/moq/lite/MoqLiteSession.kt
@@ -553,6 +553,16 @@ class MoqLiteSession internal constructor(
                         MoqLiteControlType.Subscribe -> {
                             val subPayload = buffer.readSizePrefixed() ?: return@collect
                             val sub = MoqLiteCodec.decodeSubscribe(subPayload)
+                            // Register the subscription BEFORE sending Ok so the
+                            // peer's observation of Ok is a happens-after of
+                            // `inboundSubs += sub`. Otherwise on dispatchers that
+                            // resume the peer's `bidi.incoming().first()`
+                            // continuation before this coroutine's continuation
+                            // (notably Windows under Dispatchers.Default), the
+                            // peer's first `publisher.send` after Ok races the
+                            // registration and observes an empty subscriber set.
+                            publisher.registerInboundSubscription(sub)
+                            inboundSub = sub
                             bidi.write(
                                 MoqLiteCodec.encodeSubscribeOk(
                                     MoqLiteSubscribeOk(
@@ -564,8 +574,6 @@ class MoqLiteSession internal constructor(
                                     ),
                                 ),
                             )
-                            publisher.registerInboundSubscription(sub)
-                            inboundSub = sub
                             dispatched = true
                         }