Clean up junk from gradle's user home (~/.gradle/.tmp). #14385

gradle/hacks/wipe-temp.gradle

@@ -14,15 +14,35 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */ 
+import java.nio.file.Files
+import java.time.temporal.ChronoUnit
+import java.time.Instant
+
 
 // See LUCENE-9471. We redirect temporary location for gradle
 // so that it doesn't pollute user's tmp. Wipe it during a clean though.
 
 configure(rootProject) {
   gradle.buildFinished {
+    // we clean up the java.io.tmpdir we've redirected gradle to use (LUCENE-9471). 
+    // these are still used and populated with junk.
     rootProject.delete fileTree(".gradle/tmp").matching {
       include "gradle-worker-classpath*"
     }
+
+    // clean up any files older than 3 hours from the user's gradle temp. the time
+    // limit is added so that we don't interfere with any concurrent builds... just in case.
+    def gradleTmp = rootProject.gradle.gradleUserHomeDir.toPath().resolve(".tmp")
+    if (Files.exists(gradleTmp)) {
+      Instant deadline = Instant.now().minus(3, ChronoUnit.HOURS);
+      try (var stream = Files.list(gradleTmp)) {
+        stream.forEach(path -> {
+          if (Files.getLastModifiedTime(path).toInstant().isBefore(deadline)) {
+            Files.deleteIfExists(path);
+          }
+        });
+      }
+    }
   }
 }