SQL: Ban PrintWriter#println in CLI (elastic/x-pack-elasticsearch#4118)

`PrintWriter#println` doesn't pay attention to the terminal
configuration that we specify so it breaks tests on Windows. If we
instead always use `PrintWriter#print('\n')` then the tests work
properly on windows *and* the CLI actually works properly on Windows.

relates elastic/x-pack-elasticsearch#4109

Original commit: elastic/x-pack-elasticsearch@ac17e691c8

plugin/sql/sql-cli/build.gradle

@@ -68,6 +68,14 @@ artifacts  {
     nodeps nodepsJar
 }
 
+
+forbiddenApisMain {
+    signaturesURLs += file('src/forbidden/cli-signatures.txt').toURI().toURL()
+}
+forbiddenApisTest {
+    signaturesURLs += file('src/forbidden/cli-signatures.txt').toURI().toURL()
+}
+
 thirdPartyAudit.excludes = [
     // jLine's optional dependencies
     'org.apache.sshd.client.SshClient',

plugin/sql/sql-cli/src/forbidden/cli-signatures.txt

@@ -0,0 +1,3 @@
+@defaultMessage println doesn't pay attention to terminal type so it breaks tests on Windows. Just use \n.
+java.io.PrintWriter#println()
+java.io.PrintWriter#println(java.lang.String)

plugin/sql/sql-cli/src/main/java/org/elasticsearch/xpack/sql/cli/JLineTerminal.java

@@ -71,7 +71,8 @@ public class JLineTerminal implements CliTerminal {
 
     @Override
     public void println(String text) {
-        terminal.writer().println(text);
+        print(text);
+        print("\n");
     }
 
     @Override
@@ -86,7 +87,7 @@ public class JLineTerminal implements CliTerminal {
 
     @Override
     public void println() {
-        terminal.writer().println();
+        print("\n");
     }
 
     @Override
@@ -168,7 +169,7 @@ public class JLineTerminal implements CliTerminal {
         }
 
         public void ln() {
-            terminal.writer().println(line.toAnsi(terminal));
+            println(line.toAnsi(terminal));
         }
 
         public void end() {

qa/sql/src/main/java/org/elasticsearch/xpack/qa/sql/cli/EmbeddedCli.java

@@ -25,19 +25,10 @@ import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.PipedInputStream;
 import java.io.PipedOutputStream;
-import java.io.PrintWriter;
-import java.net.InetAddress;
-import java.net.Socket;
-import java.net.UnknownHostException;
 import java.nio.charset.StandardCharsets;
-import java.security.AccessController;
-import java.security.PrivilegedAction;
 import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Predicate;
@@ -46,7 +37,6 @@ import static org.elasticsearch.test.ESTestCase.randomBoolean;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.endsWith;
 import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.startsWith;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
@@ -54,7 +44,7 @@ import static org.junit.Assert.fail;
 /**
  * Wraps a CLI in as "real" a way as it can get without forking the CLI
  * subprocess with the goal being integration testing of the CLI without
- * breaking out security model by forking. We test the script that starts
+ * breaking our security model by forking. We test the script that starts
  * the CLI using packaging tests which is super "real" but not super fast
  * and doesn't run super frequently.
  */