Reduce default size of diagnostic buffer for `FlightRecorderInputStre…

…am` from 1MiB to 1KiB (#9887)

cli/src/main/java/hudson/cli/FlightRecorderInputStream.java

@@ -21,7 +21,7 @@ class FlightRecorderInputStream extends InputStream {
      * Size (in bytes) of the flight recorder ring buffer used for debugging remoting issues.
      * @since 2.41
      */
-    static final int BUFFER_SIZE = Integer.getInteger("hudson.remoting.FlightRecorderInputStream.BUFFER_SIZE", 1024 * 1024);
+    static final int BUFFER_SIZE = Integer.getInteger("hudson.remoting.FlightRecorderInputStream.BUFFER_SIZE", 1024);
 
     private final InputStream source;
     private ByteArrayRingBuffer recorder = new ByteArrayRingBuffer(BUFFER_SIZE);

test/src/test/java/hudson/cli/PlainCLIProtocolTest.java

@@ -0,0 +1,61 @@
+package hudson.cli;
+
+import static org.awaitility.Awaitility.await;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.hasItem;
+
+import java.io.IOException;
+import java.io.PipedInputStream;
+import java.io.PipedOutputStream;
+import java.util.logging.Level;
+import org.junit.Rule;
+import org.junit.jupiter.api.Test;
+import org.jvnet.hudson.test.LoggerRule;
+
+public class PlainCLIProtocolTest {
+
+    @Rule public LoggerRule logger = new LoggerRule().record(PlainCLIProtocol.class, Level.FINE).capture(50);
+
+    @Test
+    public void streamCorruption() throws Exception {
+        final PipedOutputStream upload = new PipedOutputStream();
+        final PipedOutputStream download = new PipedOutputStream();
+
+        class Server extends PlainCLIProtocol.ServerSide {
+            Server() throws IOException {
+                super(new PlainCLIProtocol.FramedOutput(download));
+            }
+
+            @Override
+            protected void onArg(String text) {}
+
+            @Override
+            protected void onLocale(String text) {}
+
+            @Override
+            protected void onEncoding(String text) {}
+
+            @Override
+            protected synchronized void onStart() {}
+
+            @Override
+            protected void onStdin(byte[] chunk) throws IOException {}
+
+            @Override
+            protected void onEndStdin() throws IOException {}
+
+            @Override
+            protected void handleClose() {}
+        }
+
+        Server server = new Server();
+        new PlainCLIProtocol.FramedReader(server, new PipedInputStream(upload)).start();
+        // Trigger corruption
+        upload.write(0xFF);
+        upload.write(0xFF);
+        upload.write(0xFF);
+        upload.write(0xFF);
+        upload.flush();
+        await().until(logger::getMessages, hasItem(containsString("Read back: 0xff 0xff 0xff 0xff")));
+    }
+}