From dc4dbcc70dbd4c1139b2229fde5480194ef3ec1d Mon Sep 17 00:00:00 2001
From: Dmitry Khalanskiy <Dmitry.Khalanskiy@jetbrains.com>
Date: Thu, 25 Nov 2021 08:43:00 +0300
Subject: [PATCH] Fix crashes with the test module on the JVM

Now the test module correctly exposes that initially the Main
dispatcher is missing, so the default delay mechanism is not
rewritten.
---
 kotlinx-coroutines-core/jvm/src/internal/MainDispatchers.kt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kotlinx-coroutines-core/jvm/src/internal/MainDispatchers.kt b/kotlinx-coroutines-core/jvm/src/internal/MainDispatchers.kt
index 2da633a6b6..e87952b419 100644
--- a/kotlinx-coroutines-core/jvm/src/internal/MainDispatchers.kt
+++ b/kotlinx-coroutines-core/jvm/src/internal/MainDispatchers.kt
@@ -61,7 +61,9 @@ public fun MainDispatcherFactory.tryCreateDispatcher(factories: List<MainDispatc
 
 /** @suppress */
 @InternalCoroutinesApi
-public fun MainCoroutineDispatcher.isMissing(): Boolean = this is MissingMainCoroutineDispatcher
+public fun MainCoroutineDispatcher.isMissing(): Boolean =
+    // not checking `this`, as it may be wrapped in a `TestMainDispatcher`, whereas `immediate` never is.
+    this.immediate is MissingMainCoroutineDispatcher
 
 // R8 optimization hook, not const on purpose to enable R8 optimizations via "assumenosideeffects"
 @Suppress("MayBeConstant")