Add a test for upstream bug SSHD-1028

SSHD-1028:[1] server doesn't close server-side sessions properly when
client disconnects.

[1] https://issues.apache.org/jira/projects/SSHD/issues/SSHD-1028

Change-Id: I0d67f49e35abe8375cb1370a494dc01d0fb2c9b1
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

org.eclipse.jgit.junit.ssh/src/org/eclipse/jgit/junit/ssh/SshTestGitServer.java

@@ -22,6 +22,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 
 import org.apache.sshd.common.NamedResource;
 import org.apache.sshd.common.PropertyResolverUtils;
@@ -297,6 +298,17 @@ public class SshTestGitServer {
 				DefaultKeyboardInteractiveAuthenticator.INSTANCE);
 	}
 
+	/**
+	 * Retrieves the server's property map. This is a live map; changing it
+	 * affects the server.
+	 *
+	 * @return a live map of the server's properties
+	 * @since 5.9
+	 */
+	public Map<String, Object> getProperties() {
+		return server.getProperties();
+	}
+
 	/**
 	 * Starts the test server, listening on a random port.
 	 *

org.eclipse.jgit.ssh.apache.test/META-INF/MANIFEST.MF

@@ -15,6 +15,8 @@ Import-Package: org.apache.sshd.client.config.hosts;version="[2.4.0,2.5.0)",
  org.apache.sshd.common.session;version="[2.4.0,2.5.0)",
  org.apache.sshd.common.util.net;version="[2.4.0,2.5.0)",
  org.apache.sshd.common.util.security;version="[2.4.0,2.5.0)",
+ org.apache.sshd.server;version="[2.4.0,2.5.0)",
+ org.eclipse.jgit.api;version="[5.9.0,5.10.0)",
  org.eclipse.jgit.api.errors;version="[5.9.0,5.10.0)",
  org.eclipse.jgit.internal.transport.sshd.proxy;version="[5.9.0,5.10.0)",
  org.eclipse.jgit.junit;version="[5.9.0,5.10.0)",

org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/transport/sshd/ApacheSshTest.java

@@ -21,6 +21,8 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
 import org.apache.sshd.client.config.hosts.KnownHostEntry;
+import org.apache.sshd.server.ServerFactoryManager;
+import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.TransportException;
 import org.eclipse.jgit.junit.ssh.SshTestBase;
 import org.eclipse.jgit.lib.Constants;
@@ -175,4 +177,31 @@ public class ApacheSshTest extends SshTestBase {
 				defaultCloneDir, null,
 				"IdentityFile " + privateKey1.getAbsolutePath());
 	}
+
+	/**
+	 * Test for SSHD-1028. If the server doesn't close sessions, the second
+	 * fetch will fail. Occurs on sshd 2.5.[01].
+	 *
+	 * @throws Exception
+	 *             on errors
+	 * @see <a href=
+	 *      "https://issues.apache.org/jira/projects/SSHD/issues/SSHD-1028">SSHD-1028</a>
+	 */
+	@Test
+	public void testPushWithSessionLimit() throws Exception {
+		server.getProperties().put(ServerFactoryManager.MAX_CONCURRENT_SESSIONS,
+				Integer.valueOf(2));
+		File localClone = cloneWith("ssh://localhost/doesntmatter",
+				defaultCloneDir, null, //
+				"Host localhost", //
+				"HostName localhost", //
+				"Port " + testPort, //
+				"User " + TEST_USER, //
+				"IdentityFile " + privateKey1.getAbsolutePath());
+		// Fetch a couple of times
+		try (Git git = Git.open(localClone)) {
+			git.fetch().call();
+			git.fetch().call();
+		}
+	}
 }