From d16a1b14d888e4768c35a53885eb94d1697d94e6 Mon Sep 17 00:00:00 2001
From: Vladimir Dolzhenko <vladimir.dolzhenko@jetbrains.com>
Date: Thu, 24 Oct 2019 13:14:04 +0200
Subject: [PATCH] Acquire lock for several seconds to create LightClasses to
 workaround dead-lock over resolve

Relates to #KT-34279
---
 .../classes/KotlinClassInnerStuffCache.kt     | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KotlinClassInnerStuffCache.kt b/compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KotlinClassInnerStuffCache.kt
index c379f4e70b9..a8619b70c34 100644
--- a/compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KotlinClassInnerStuffCache.kt
+++ b/compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/KotlinClassInnerStuffCache.kt
@@ -21,13 +21,15 @@ import com.intellij.psi.util.CachedValueProvider
 import com.intellij.util.ArrayUtil
 import com.intellij.util.containers.ContainerUtil
 import gnu.trove.THashMap
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.locks.ReentrantLock
 
 class KotlinClassInnerStuffCache(val myClass: PsiExtensibleClass, externalDependencies: List<Any>) {
     private val myTracker = SimpleModificationTracker()
     private val dependencies: List<Any> = externalDependencies + myTracker
 
     fun <T : Any> get(initializer: () -> T) = object : Lazy<T> {
-        // Note: holder is used as initialization monitor as well
+        private val lock = ReentrantLock()
         private val holder = lazyPub {
             PsiCachedValueImpl(PsiManager.getInstance(myClass.project),
                                CachedValueProvider<T> {
@@ -49,20 +51,29 @@ class KotlinClassInnerStuffCache(val myClass: PsiExtensibleClass, externalDepend
                     // Assumption 1: Lets say A calculation requires another value e.g. B to be calculated
                     // Assumption 2: Thread T2 wants to calculate value for B
 
-                    // to avoid dead-lock case we mark thread as doing calculation and acquire lock only once per thread
+                    // to avoid dead-lock
+                    // - we mark thread as doing calculation and acquire lock only once per thread
                     // as a trade-off to prevent dependent value could be calculated several time
                     // due to CAS (within putUserDataIfAbsent etc) the same instance of calculated value will be used
 
-                    if (!initIsRunning.get()) {
-                        synchronized(holder) {
+                    // TODO: NOTE: acquire lock for a several seconds to avoid dead-lock via resolve is a WORKAROUND
+
+                    val notRunning = !initIsRunning.get()
+                    if (notRunning && lock.tryLock(500, TimeUnit.MILLISECONDS)) {
+                        try {
                             initIsRunning.set(true)
                             try {
                                 computeValue()
                             } finally {
                                 initIsRunning.set(false)
                             }
+                        } finally {
+                            lock.unlock()
                         }
                     } else {
+                        if (notRunning) { // means unable to acquire lock within specified time limit
+                            Logger.getInstance(KotlinClassInnerStuffCache::class.java).error("failed to acquire lock for $initializer")
+                        }
                         computeValue()
                     }
                 }