Make a new ant builder per AntTask invocation

buildSrc/src/main/groovy/org/elasticsearch/gradle/AntTask.groovy

@@ -47,26 +47,26 @@ public class AntTask extends DefaultTask {
 
     @TaskAction
     final void executeTask() {
-        // capture the current loggers
-        List<BuildLogger> savedLoggers = new ArrayList<>();
-        for (BuildListener l : project.ant.project.getBuildListeners()) {
+        AntBuilder ant = new AntBuilder()
+
+        // remove existing loggers, we add our own
+        List<BuildLogger> toRemove = new ArrayList<>();
+        for (BuildListener l : ant.project.getBuildListeners()) {
             if (l instanceof BuildLogger) {
-                savedLoggers.add(l);
+                toRemove.add(l);
             }
         }
-        // remove them
-        for (BuildLogger l : savedLoggers) {
-            project.ant.project.removeBuildListener(l)
+        for (BuildLogger l : toRemove) {
+            ant.project.removeBuildListener(l)
         }
 
-        final int outputLevel = logger.isDebugEnabled() ? Project.MSG_DEBUG : Project.MSG_INFO
+        final int outputLevel = logger.isDebugEnabled() ? Project.MSG_DEBUG : (logger.isInfoEnabled() ? Project.MSG_INFO : Project.MSG_WARN)
         final PrintStream stream = useStdout() ? System.out : new PrintStream(outputBuffer, true, Charset.defaultCharset().name())
         BuildLogger antLogger = makeLogger(stream, outputLevel)
 
-        // now run the command with just our logger
-        project.ant.project.addBuildListener(antLogger)
+        ant.project.addBuildListener(antLogger)
         try {
-            runAnt(project.ant)
+            runAnt(ant)
         } catch (BuildException e) {
             // ant failed, so see if we have buffered output to emit, then rethrow the failure
             String buffer = outputBuffer.toString()
@@ -74,12 +74,6 @@ public class AntTask extends DefaultTask {
                 logger.error("=== Ant output ===\n${buffer}")
             }
             throw e
-        } finally {
-            project.ant.project.removeBuildListener(antLogger)
-            // add back the old loggers before returning
-            for (BuildLogger l : savedLoggers) {
-                project.ant.project.addBuildListener(l)
-            }
         }
     }
 

buildSrc/src/main/groovy/org/elasticsearch/gradle/precommit/LicenseHeadersTask.groovy

@@ -35,16 +35,13 @@ public class LicenseHeadersTask extends AntTask {
 
     LicenseHeadersTask() {
         description = "Checks sources for missing, incorrect, or unacceptable license headers"
-
-        if (ant.project.taskDefinitions.contains('ratReport') == false) {
-            ant.project.addTaskDefinition('ratReport', Report)
-            ant.project.addDataTypeDefinition('substringMatcher', SubstringLicenseMatcher)
-            ant.project.addDataTypeDefinition('approvedLicense', SimpleLicenseFamily)
-        }
     }
 
     @Override
     protected void runAnt(AntBuilder ant) {
+        ant.project.addTaskDefinition('ratReport', Report)
+        ant.project.addDataTypeDefinition('substringMatcher', SubstringLicenseMatcher)
+        ant.project.addDataTypeDefinition('approvedLicense', SimpleLicenseFamily)
 
         // create a file for the log to go to under reports/
         File reportDir = new File(project.buildDir, "reports/licenseHeaders")

buildSrc/src/main/groovy/org/elasticsearch/gradle/precommit/ThirdPartyAuditTask.groovy

@@ -18,24 +18,19 @@
  */
 package org.elasticsearch.gradle.precommit
 
+import org.apache.tools.ant.BuildLogger
 import org.apache.tools.ant.DefaultLogger
+import org.apache.tools.ant.Project
 import org.elasticsearch.gradle.AntTask
 import org.gradle.api.artifacts.Configuration
+import org.gradle.api.file.FileCollection
 
-import java.nio.file.Files
 import java.nio.file.FileVisitResult
+import java.nio.file.Files
 import java.nio.file.Path
 import java.nio.file.SimpleFileVisitor
 import java.nio.file.attribute.BasicFileAttributes
 
-import org.gradle.api.DefaultTask
-import org.gradle.api.artifacts.UnknownConfigurationException
-import org.gradle.api.file.FileCollection
-import org.gradle.api.tasks.TaskAction
-
-import org.apache.tools.ant.BuildLogger
-import org.apache.tools.ant.Project
-
 /**
  * Basic static checking to keep tabs on third party JARs
  */
@@ -50,10 +45,6 @@ public class ThirdPartyAuditTask extends AntTask {
     ThirdPartyAuditTask() {
         dependsOn(project.configurations.testCompile)
         description = "Checks third party JAR bytecode for missing classes, use of internal APIs, and other horrors'"
-
-        if (ant.project.taskDefinitions.contains('thirdPartyAudit') == false) {
-            ant.project.addTaskDefinition('thirdPartyAudit', de.thetaphi.forbiddenapis.ant.AntTask)
-        }
     }
 
     /** 
@@ -103,6 +94,8 @@ public class ThirdPartyAuditTask extends AntTask {
 
     @Override
     protected void runAnt(AntBuilder ant) {
+        ant.project.addTaskDefinition('thirdPartyAudit', de.thetaphi.forbiddenapis.ant.AntTask)
+
         // we only want third party dependencies.
         FileCollection jars = project.configurations.testCompile.fileCollection({ dependency ->
             dependency.group.startsWith("org.elasticsearch") == false