From f2021b580e57a24da03a1b188ee4bbf99f20cdfd Mon Sep 17 00:00:00 2001
From: Alexey Tsvetkov <alexey.tsvetkov@jetbrains.com>
Date: Mon, 10 Jun 2019 22:08:11 +0300
Subject: [PATCH] Do not fork java compile tasks when current JDK can be used

I see the following improvements:
* `clean dist --parallel` is ~10% faster (from 3:40 to 3:20)
* incremental `dist --parallel` is ~50% faster
(adding public method to org.jetbrains.kotlin.utils.SmartList)
---
 build.gradle.kts | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/build.gradle.kts b/build.gradle.kts
index f66070484f1..92b0cd98ba3 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -716,12 +716,23 @@ fun jdkPath(version: String): String {
 
 
 fun Project.configureJvmProject(javaHome: String, javaVersion: String) {
+    val currentJavaHome = File(System.getProperty("java.home")!!).canonicalPath
+    val shouldFork = !currentJavaHome.startsWith(File(javaHome).canonicalPath)
+
     tasks.withType<JavaCompile> {
         if (name != "compileJava9Java") {
             sourceCompatibility = javaVersion
             targetCompatibility = javaVersion
-            options.isFork = true
-            options.forkOptions.javaHome = file(javaHome)
+
+            if (shouldFork) {
+                logger.info("$path will be forked with $javaHome")
+                options.isFork = true
+                options.forkOptions.javaHome = file(javaHome)
+            } else {
+                options.isFork = false
+                options.forkOptions.javaHome = null
+            }
+
             options.compilerArgs.add("-proc:none")
             options.encoding = "UTF-8"
         }