ClosedFileSystemException or NullPointerException thrown when SharedArchivePathTree is opened and closed concurrently

independent-projects/bootstrap/app-model/src/main/java/io/quarkus/paths/SharedArchivePathTree.java

@@ -60,11 +60,11 @@ public OpenPathTree open() {
             }
         }
         try {
-            this.lastOpen = new SharedOpenArchivePathTree(openFs());
+            lastOpen = this.lastOpen = new SharedOpenArchivePathTree(openFs());
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
-        return new CallerOpenPathTree(this.lastOpen);
+        return new CallerOpenPathTree(lastOpen);
     }
 
     private class SharedOpenArchivePathTree extends OpenArchivePathTree {

independent-projects/bootstrap/app-model/src/test/java/io/quarkus/paths/SharedArchivePathTreeTest.java

@@ -0,0 +1,85 @@
+package io.quarkus.paths;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class SharedArchivePathTreeTest {
+    private static final int WORKERS_COUNT = 128;
+
+    @Test
+    void nullPointerException() throws IOException, InterruptedException, ExecutionException {
+        /* Reproduce https://github.com/quarkusio/quarkus/issues/48220 */
+        stress((OpenPathTree opened) -> {
+        });
+    }
+
+    @Test
+    void closedFileSystemException() throws IOException, InterruptedException, ExecutionException {
+        /* Reproduce https://github.com/quarkusio/quarkus/issues/48220 */
+        stress((OpenPathTree opened) -> {
+            try {
+                Path p = opened.getPath("org/assertj/core/api/Assertions.class");
+                Files.readAllBytes(p);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        });
+    }
+
+    static void stress(Consumer<OpenPathTree> consumer) throws IOException {
+        /* Find assertj-core jar in the class path */
+        final String rawCp = System.getProperty("java.class.path");
+        final String assertjCoreJarPath = Stream.of(rawCp.split(System.getProperty("path.separator")))
+                .filter(p -> p.contains("assertj-core"))
+                .findFirst()
+                .orElseThrow(() -> new AssertionError("Could not find assertj-core  in " + rawCp));
+
+        /* Create a copy of assertj-core jar in target directory */
+        final Path assertjCoreJarPathCopy = Path.of("target/assertj-core-" + UUID.randomUUID() + ".jar");
+        if (!Files.exists(assertjCoreJarPathCopy.getParent())) {
+            Files.createDirectories(assertjCoreJarPathCopy.getParent());
+        }
+        Files.copy(Path.of(assertjCoreJarPath), assertjCoreJarPathCopy);
+
+        /* Now do some concurrent opening and closing of the SharedArchivePathTree instance */
+        final ArchivePathTree archivePathTree = SharedArchivePathTree.forPath(assertjCoreJarPathCopy);
+        final ExecutorService executor = Executors.newFixedThreadPool(WORKERS_COUNT);
+        final List<Future<Void>> futures = new ArrayList<>(WORKERS_COUNT);
+        try {
+            for (int i = 0; i < WORKERS_COUNT; i++) {
+                final Future<Void> f = executor.submit(() -> {
+                    try (OpenPathTree opened = archivePathTree.open()) {
+                        consumer.accept(opened);
+                    }
+                    return null;
+                });
+                futures.add(f);
+            }
+
+            // Ensure all tasks are completed
+            int i = 0;
+            for (Future<Void> future : futures) {
+                Assertions.assertThat(future)
+                        .describedAs("Expected success at iteration %d", i++)
+                        .succeedsWithin(30, TimeUnit.SECONDS);
+            }
+        } finally {
+            executor.shutdown();
+        }
+    }
+
+}