Reset SSH connection and credentials on "Auth fail"

When SSH user/password authentication failed this may have been caused
by changed credentials on the server side. When the SSH credentials of a
user change the SSH connection needs to be re-established and
credentials which may have been stored by the credentials provider
need to be reset in order to enable prompting for the new credentials.

Bug: 356233
Change-Id: I7d64c5f39b68a9687c858bb68a961616eabbc751
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/transport/CredentialsProvider.java

@@ -134,4 +134,13 @@ public abstract class CredentialsProvider {
 			throws UnsupportedCredentialItem {
 		return get(uri, items.toArray(new CredentialItem[items.size()]));
 	}
+
+	/**
+	 * Reset the credentials provider for the given URI
+	 *
+	 * @param uri
+	 */
+	public void reset(URIish uri) {
+		// default does nothing
+	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/transport/JschConfigSessionFactory.java

@@ -106,6 +106,46 @@ public abstract class JschConfigSessionFactory extends SshSessionFactory {
 			if (user == null)
 				user = hc.getUser();
 
+			Session session = createSession(credentialsProvider, fs, user,
+					pass, host, port, hc);
+
+			int retries = 0;
+			while (!session.isConnected() && retries < 3) {
+				try {
+					retries++;
+					session.connect(tms);
+				} catch (JSchException e) {
+					session.disconnect();
+					session = null;
+					// if authentication failed maybe credentials changed at the
+					// remote end therefore reset credentials and retry
+					if (credentialsProvider != null && e.getCause() == null
+							&& e.getMessage().equals("Auth fail")) {
+						credentialsProvider.reset(uri);
+						session = createSession(credentialsProvider, fs, user,
+								pass, host, port, hc);
+					} else {
+						throw e;
+					}
+				}
+			}
+
+			return new JschSession(session, uri);
+
+		} catch (JSchException je) {
+			final Throwable c = je.getCause();
+			if (c instanceof UnknownHostException)
+				throw new TransportException(uri, JGitText.get().unknownHost);
+			if (c instanceof ConnectException)
+				throw new TransportException(uri, c.getMessage());
+			throw new TransportException(uri, je.getMessage(), je);
+		}
+
+	}
+
+	private Session createSession(CredentialsProvider credentialsProvider,
+			FS fs, String user, final String pass, String host, int port,
+			final OpenSshConfig.Host hc) throws JSchException {
 		final Session session = createSession(hc, user, host, port, fs);
 		if (pass != null)
 			session.setPassword(pass);
@@ -123,21 +163,7 @@ public abstract class JschConfigSessionFactory extends SshSessionFactory {
 					credentialsProvider));
 		}
 		configure(hc, session);
-
-			if (!session.isConnected())
-				session.connect(tms);
-
-			return new JschSession(session, uri);
-
-		} catch (JSchException je) {
-			final Throwable c = je.getCause();
-			if (c instanceof UnknownHostException)
-				throw new TransportException(uri, JGitText.get().unknownHost);
-			if (c instanceof ConnectException)
-				throw new TransportException(uri, c.getMessage());
-			throw new TransportException(uri, je.getMessage(), je);
-		}
-
+		return session;
 	}
 
 	/**