ExecDumpClient should report error when no data is retrieved (#538)

org.jacoco.core.test/src/org/jacoco/core/tools/ExecDumpClientTest.java

@@ -17,6 +17,7 @@
 import static org.junit.Assert.fail;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.ConnectException;
 import java.net.InetAddress;
 import java.net.ServerSocket;
@@ -31,7 +32,9 @@
 import org.jacoco.core.runtime.RemoteControlWriter;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 
 /**
  * Unit tests for {@link ExecDumpClient}.
@@ -46,6 +49,9 @@ public class ExecDumpClientTest {
 
 	private ServerSocket server;
 
+	@Rule
+	public ExpectedException exception = ExpectedException.none();
+
 	@Before
 	public void setup() {
 		callbacks = new ArrayList<String>();
@@ -101,7 +107,7 @@ public void testWithRetries() throws IOException {
 				// 3. Retry
 				"onConnectionFailure", "onConnecting")
 
-		, callbacks);
+				, callbacks);
 	}
 
 	@Test
@@ -126,6 +132,16 @@ public void testReset() throws IOException {
 		assertTrue(resetRequested);
 	}
 
+	@Test
+	public void should_throw_IOException_when_server_closes_connection_without_response()
+			throws IOException {
+		exception.expect(IOException.class);
+		exception.expectMessage("Socket closed unexpectedly.");
+
+		int port = createNopServer();
+		client.dump((String) null, port);
+	}
+
 	private int getFreePort() throws IOException {
 		final ServerSocket server = new ServerSocket(0, 0,
 				InetAddress.getByName(null));
@@ -159,11 +175,40 @@ public void visitDumpCommand(boolean dump, boolean reset)
 				dumpRequested = dump;
 				resetRequested = reset;
 				if (dump) {
-					writer.visitSessionInfo(new SessionInfo("TestId", 100, 200));
+					writer.visitSessionInfo(
+							new SessionInfo("TestId", 100, 200));
 				}
 				writer.sendCmdOk();
 			}
 		});
 		reader.read();
 	}
+
+	private int createNopServer() throws IOException {
+		server = new ServerSocket(0, 0, InetAddress.getByName(null));
+		new Thread(new Runnable() {
+			public void run() {
+				try {
+					Socket socket = server.accept();
+					InputStream in = socket.getInputStream();
+					// Read Header:
+					in.read();
+					in.read();
+					in.read();
+					in.read();
+					in.read();
+					// Read Dump Command:
+					in.read();
+					in.read();
+					in.read();
+					// Then just close connection without any response:
+					socket.close();
+				} catch (IOException e) {
+					// ignore
+				}
+			}
+		}).start();
+		return server.getLocalPort();
+	}
+
 }

org.jacoco.core/src/org/jacoco/core/tools/ExecDumpClient.java

@@ -123,7 +123,10 @@ public ExecFileLoader dump(final InetAddress address, final int port)
 					.setExecutionDataVisitor(loader.getExecutionDataStore());
 
 			remoteWriter.visitDumpCommand(dump, reset);
-			remoteReader.read();
+
+			if (!remoteReader.read()) {
+				throw new IOException("Socket closed unexpectedly.");
+			}
 
 		} finally {
 			socket.close();

org.jacoco.doc/docroot/doc/changes.html

@@ -43,6 +43,13 @@ <h3>New Features</h3>
       (GitHub <a href="https://github.com/jacoco/jacoco/issues/498">#498</a>).</li>
 </ul>
 
+<h3>Fixed Bugs</h3>
+<ul>
+  <li><code>dump</code> commands now report error when server unexpectedly
+      closes connection without sending response
+      (GitHub <a href="https://github.com/jacoco/jacoco/issues/538">#538</a>).</li>
+</ul>
+
 <h3>Non-functional Changes</h3>
 <ul>
   <li>More information about context is provided when unable to read input during

org.jacoco.examples/src/org/jacoco/examples/ExecutionDataClient.java

@@ -55,7 +55,9 @@ public static void main(final String[] args) throws IOException {
 
 		// Send a dump command and read the response:
 		writer.visitDumpCommand(true, false);
-		reader.read();
+		if (!reader.read()) {
+			throw new IOException("Socket closed unexpectedly.");
+		}
 
 		socket.close();
 		localFile.close();