chore: Patch smoke test forked processes to use a custom preference file

Author: bric3

dd-java-agent/agent-ci-visibility/civisibility-test-fixtures/src/main/groovy/datadog/trace/civisibility/CiVisibilitySmokeTest.groovy

@@ -100,9 +100,8 @@ abstract class CiVisibilitySmokeTest extends Specification {
   }
 
   /**
-   * Trick to prevent jul Prefs file lock issue on forked processes.
-   *
-   * Reason: multiple observations of failed job with
+   * Trick to prevent jul Prefs file lock issue on forked processes, in particular in CI which
+   * runs on Linux and have competing processes trying to write to it, including the Gradle daemon.
    *
    * <pre><code>
    * Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.

dd-smoke-tests/debugger-integration-tests/src/test/java/datadog/smoketest/ProcessBuilderHelper.java

@@ -28,6 +28,20 @@ public static ProcessBuilder createProcessBuilder(
       String mainClassName,
       String... params) {
 
+    // Trick to prevent jul preferences file lock issue on forked processes, in particular in CI
+    // which runs on Linux and have competing processes trying to write to it, including the
+    // Gradle daemon.
+    //
+    //   Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
+    String prefsDir =
+        System.getProperty("java.io.tmpdir")
+            + File.separator
+            + "userPrefs"
+            + File.separator
+            + mainClassName
+            + "_"
+            + System.nanoTime();
+
     List<String> baseCommand =
         Arrays.asList(
             javaPath(),
@@ -37,7 +51,8 @@ public static ProcessBuilder createProcessBuilder(
             "-javaagent:" + agentShadowJar(),
             "-XX:ErrorFile=/tmp/hs_err_pid%p.log",
             "-Ddd.env=smoketest",
-            "-Ddd.version=99");
+            "-Ddd.version=99",
+            "-Djava.util.prefs.userRoot=" + prefsDir);
 
     List<String> command = new ArrayList<>();
     command.addAll(baseCommand);

dd-smoke-tests/src/main/groovy/datadog/smoketest/AbstractSmokeTest.groovy

@@ -188,6 +188,12 @@ abstract class AbstractSmokeTest extends ProcessManager {
   def javaProperties() {
     def tmpDir = "/tmp"
 
+    // Trick to prevent jul preferences file lock issue on forked processes, in particular in CI which
+    // runs on Linux and have competing processes trying to write to it, including the Gradle daemon.
+    //
+    //   Couldn't flush user prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
+    def prefsDir = "${tmpDir}/userPrefs/${this.getClass().simpleName}_${System.nanoTime()}"
+
     def ret = [
       "${getMaxMemoryArgumentForFork()}",
       "${getMinMemoryArgumentForFork()}",
@@ -204,7 +210,8 @@ abstract class AbstractSmokeTest extends ProcessManager {
       "-Ddd.profiling.ddprof.alloc.enabled=${isDdprofSafe()}",
       "-Ddatadog.slf4j.simpleLogger.defaultLogLevel=${logLevel()}",
       "-Dorg.slf4j.simpleLogger.defaultLogLevel=${logLevel()}",
-      "-Ddd.site="
+      "-Ddd.site=",
+      "-Djava.util.prefs.userRoot=${prefsDir}"
     ]
     if (inferServiceName())  {
       ret += "-Ddd.service.name=${SERVICE_NAME}"