From ef177e7a04c60a1f0e71fe26ae2879ba22afa087 Mon Sep 17 00:00:00 2001
From: Eldar Abusalimov <eldar.abusalimov@jetbrains.com>
Date: Wed, 6 Nov 2019 04:24:19 +0300
Subject: [PATCH] Expiration: Fix race with GC when handling already disposed
 Disposable

On a rare occasion an instance of DisposableExpiration created for an
already disposed Disposable could have been left non-expired. This used
to happen when the GC had already collected a weakly-referenced child
disposable by the time we disposed the instance of
eakReferenceDisposableWrapper referencing the child.

This also fixes
NonBlockingReadActionTest.testSyncExecutionThrowsPCEWhenExpired failing
randomly.

GitOrigin-RevId: 28dfeef0e7d1ef501db0554a5d8069f82603211d
---
 .../openapi/application/constraints/Expiration.kt        | 2 ++
 .../openapi/application/constraints/ExpirationTest.kt    | 9 ++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/platform/platform-impl/src/com/intellij/openapi/application/constraints/Expiration.kt b/platform/platform-impl/src/com/intellij/openapi/application/constraints/Expiration.kt
index aeb64f46cfc5..f4702522c8ae 100644
--- a/platform/platform-impl/src/com/intellij/openapi/application/constraints/Expiration.kt
+++ b/platform/platform-impl/src/com/intellij/openapi/application/constraints/Expiration.kt
@@ -5,6 +5,7 @@ import com.intellij.openapi.Disposable
 import com.intellij.openapi.WeakReferenceDisposableWrapper
 import com.intellij.openapi.util.Disposer
 import com.intellij.util.IncorrectOperationException
+import com.intellij.util.ObjectUtils
 import kotlinx.coroutines.*
 
 /**
@@ -146,6 +147,7 @@ internal fun Disposable.cancelJobOnDisposal(job: Job,
 
   if (!tryRegisterDisposable(this, childRef)) {
     Disposer.dispose(childRef)  // runs disposableBlock()
+    ObjectUtils.reachabilityFence(child)
     return AutoCloseable { }
   }
   else {
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/application/constraints/ExpirationTest.kt b/platform/platform-tests/testSrc/com/intellij/openapi/application/constraints/ExpirationTest.kt
index a3e620865063..674af5784e84 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/application/constraints/ExpirationTest.kt
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/application/constraints/ExpirationTest.kt
@@ -12,7 +12,7 @@ import kotlinx.coroutines.Job
 class ExpirationTest : LightPlatformTestCase() {
 
   private fun createTestDisposable(): Disposable {
-    return Disposable { }.also { Disposer.register(testRootDisposable, it) }
+    return Disposer.newDisposable(name).also { Disposer.register(testRootDisposable, it) }
   }
 
   private fun createCompositeExpiration(vararg expiration: Expiration): Expiration {
@@ -20,6 +20,13 @@ class ExpirationTest : LightPlatformTestCase() {
     return Expiration.composeExpiration(expiration.toList())!!
   }
 
+  fun `test isExpired for already disposed Disposable`() {
+    val disposable = createTestDisposable()
+    Disposer.dispose(disposable)
+    val expiration = DisposableExpiration(disposable)
+    assertTrue("Expiration.isExpired must be true", expiration.isExpired)
+  }
+
   fun `test isExpired for JobExpiration`() {
     val job = Job()
     val expiration = JobExpiration(job)