From 212d4d3c71ef4bdbc9eee442ae72cecc30326c67 Mon Sep 17 00:00:00 2001
From: Nikolay Martynov <mar.kolya@gmail.com>
Date: Fri, 29 Mar 2019 10:59:18 -0400
Subject: [PATCH] Provide Java compiler with bootstrap classes for Java7

when compiling Java7-compatible sources.
---
 .../aws/v2/AwsClientInstrumentation.java        |  2 +-
 .../aws/v2/AwsHttpClientInstrumentation.java    |  2 +-
 .../aws/v2/TracingExecutionInterceptor.java     | 13 +++++++++++--
 gradle/java.gradle                              | 17 +++++++++++++++++
 4 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsClientInstrumentation.java b/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsClientInstrumentation.java
index 47f2a5b07e..3bcf026a6b 100644
--- a/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsClientInstrumentation.java
+++ b/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsClientInstrumentation.java
@@ -37,7 +37,7 @@ public final class AwsClientInstrumentation extends AbstractAwsClientInstrumenta
 
     @Advice.OnMethodEnter(suppress = Throwable.class)
     public static void methodEnter(@Advice.This final SdkClientBuilder thiz) {
-      thiz.overrideConfiguration(TracingExecutionInterceptor.getOverrideConfigurationConsumer());
+      TracingExecutionInterceptor.overrideConfiguration(thiz);
     }
   }
 }
diff --git a/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsHttpClientInstrumentation.java b/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsHttpClientInstrumentation.java
index e7777ca723..aa10e1ede0 100644
--- a/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsHttpClientInstrumentation.java
+++ b/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java/datadog/trace/instrumentation/aws/v2/AwsHttpClientInstrumentation.java
@@ -81,7 +81,7 @@ public final class AwsHttpClientInstrumentation extends AbstractAwsClientInstrum
      * this instrumentation when TracingExecutionInterceptor would not work.
      */
     public static void muzzleCheck() {
-      TracingExecutionInterceptor.getOverrideConfigurationConsumer();
+      TracingExecutionInterceptor.muzzleCheck();
     }
   }
 }
diff --git a/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java8/datadog/trace/instrumentation/aws/v2/TracingExecutionInterceptor.java b/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java8/datadog/trace/instrumentation/aws/v2/TracingExecutionInterceptor.java
index 377c85e0bc..4ad249fb07 100644
--- a/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java8/datadog/trace/instrumentation/aws/v2/TracingExecutionInterceptor.java
+++ b/dd-java-agent/instrumentation/aws-java-sdk-2.2/src/main/java8/datadog/trace/instrumentation/aws/v2/TracingExecutionInterceptor.java
@@ -10,6 +10,7 @@ import io.opentracing.util.GlobalTracer;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.function.Consumer;
+import software.amazon.awssdk.core.client.builder.SdkClientBuilder;
 import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
 import software.amazon.awssdk.core.interceptor.Context;
 import software.amazon.awssdk.core.interceptor.ExecutionAttribute;
@@ -84,8 +85,16 @@ public class TracingExecutionInterceptor implements ExecutionInterceptor {
     }
   }
 
-  public static Consumer<ClientOverrideConfiguration.Builder> getOverrideConfigurationConsumer() {
-    return OVERRIDE_CONFIGURATION_CONSUMER;
+  /**
+   * We keep this method here because it references Java8 classes and we would like to avoid
+   * compiling this for instrumentation code that should load into Java7.
+   */
+  public static void overrideConfiguration(final SdkClientBuilder client) {
+    client.overrideConfiguration(OVERRIDE_CONFIGURATION_CONSUMER);
+  }
+
+  public static void muzzleCheck() {
+    // Noop
   }
 
   /**
diff --git a/gradle/java.gradle b/gradle/java.gradle
index 810c262839..6f7433898c 100644
--- a/gradle/java.gradle
+++ b/gradle/java.gradle
@@ -14,6 +14,23 @@ if (applyCodeCoverage) {
 sourceCompatibility = 1.7
 targetCompatibility = 1.7
 
+[JavaCompile, ScalaCompile].each { type ->
+  tasks.withType(type) {
+    doFirst {
+      // We do this specifically for Java7 bytecode generation because we would like to be able to compile
+      // with Java8+ compiler. This likely would require some modifications when we switch to java11 compiler.
+      // Using proper Java7 bootstrap and extentions allows to be sure our code will run on real Java7.
+      if (JavaVersion.toVersion(sourceCompatibility) == JavaVersion.VERSION_1_7
+        && JavaVersion.current() != JavaVersion.VERSION_1_7
+        && System.env.JAVA_7_HOME != null) {
+        options.fork = true
+        options.bootstrapClasspath = fileTree(include: ['*.jar'], dir: "${System.env.JAVA_7_HOME}/jre/lib/")
+        options.extensionDirs = "${System.env.JAVA_7_HOME}/jre/lib/ext/"
+      }
+    }
+  }
+}
+
 apply plugin: "io.franzbecker.gradle-lombok"
 
 lombok { // optional: values below are the defaults