From 4142ca0e3299ac305f5a1295044681b0bf29aa06 Mon Sep 17 00:00:00 2001
From: Eugene Zhuravlev <jeka@intellij.com>
Date: Mon, 4 Apr 2016 14:17:14 +0200
Subject: [PATCH] if eclipse compiler is used in the project, require at least
 java7 for build process running (IDEA-154110)

---
 .../compiler/server/BuildManager.java         | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/java/compiler/impl/src/com/intellij/compiler/server/BuildManager.java b/java/compiler/impl/src/com/intellij/compiler/server/BuildManager.java
index 7e9486d771c0..fc46ad254843 100644
--- a/java/compiler/impl/src/com/intellij/compiler/server/BuildManager.java
+++ b/java/compiler/impl/src/com/intellij/compiler/server/BuildManager.java
@@ -17,8 +17,10 @@ package com.intellij.compiler.server;
 
 import com.intellij.ProjectTopics;
 import com.intellij.compiler.CompilerConfiguration;
+import com.intellij.compiler.CompilerConfigurationImpl;
 import com.intellij.compiler.CompilerWorkspaceConfiguration;
 import com.intellij.compiler.impl.CompilerUtil;
+import com.intellij.compiler.impl.javaCompiler.BackendCompiler;
 import com.intellij.compiler.impl.javaCompiler.javac.JavacConfiguration;
 import com.intellij.compiler.server.impl.BuildProcessClasspathManager;
 import com.intellij.concurrency.JobScheduler;
@@ -98,6 +100,7 @@ import org.jetbrains.jps.api.*;
 import org.jetbrains.jps.cmdline.BuildMain;
 import org.jetbrains.jps.cmdline.ClasspathBootstrap;
 import org.jetbrains.jps.incremental.Utils;
+import org.jetbrains.jps.model.java.compiler.JavaCompilers;
 import org.jetbrains.jps.model.serialization.JpsGlobalLoader;
 
 import javax.tools.*;
@@ -944,14 +947,26 @@ public class BuildManager implements Disposable {
       }
     }
 
-    final Sdk internalJdk = JavaAwareProjectJdkTableImpl.getInstanceEx().getInternalJdk();
-    if (projectJdk == null || sdkVersion == null || !sdkVersion.isAtLeast(JavaSdkVersion.JDK_1_6)) {
+    final JavaSdkVersion oldestPossible = getOldestPossiblePlatformForBuildProcess(project);
+
+    if (projectJdk == null || sdkVersion == null || !sdkVersion.isAtLeast(oldestPossible)) {
+      final Sdk internalJdk = JavaAwareProjectJdkTableImpl.getInstanceEx().getInternalJdk();
       projectJdk = internalJdk;
       sdkVersion = javaSdkType.getVersion(internalJdk);
     }
     return Pair.create(projectJdk, sdkVersion);
   }
 
+  @NotNull
+  private static JavaSdkVersion getOldestPossiblePlatformForBuildProcess(Project project) {
+    final BackendCompiler javaCompiler = ((CompilerConfigurationImpl)CompilerConfiguration.getInstance(project)).getDefaultCompiler();
+    final String id = javaCompiler != null? javaCompiler.getId() : JavaCompilers.JAVAC_ID;
+    if (id == JavaCompilers.ECLIPSE_ID || id == JavaCompilers.ECLIPSE_EMBEDDED_ID) {
+      return JavaSdkVersion.JDK_1_7; // because bundled ecj is compiled against 1.7
+    }
+    return JavaSdkVersion.JDK_1_6;
+  }
+
   private Future<Pair<RequestFuture<PreloadedProcessMessageHandler>, OSProcessHandler>> launchPreloadedBuildProcess(final Project project, ExecutorService projectTaskQueue) throws Exception {
     ensureListening();