Escape sequences are printed when using custom output stream

[krzsal]

Hi,
I am upgrading to jline3 from jline2. I solved most of the issues but I cannot get rid of few cursor control escape sequences:
[?1h= and [?1l>[?1000l.
Those sequences are printed when application is started on linux, macOS or git-bash in windows. Starting application from windows cmd or power shell will not print those escape sequences. The issue occures when custom output stream is used, the System.out works perfectly fine.
In the descibed case I needed to remove >.... but setting terminal size explicitly solved that. Also I am already using option (BRACKETED_PASTE, false).

Terminal terminal = TerminalBuilder.builder()
                .system(isSystem) // is false when issue occures
                .streams(inputStream,outputStream)
                .size(new Size(160,50))
                .build();

LineReader reader = LineReaderBuilder.builder()
                .terminal(terminal)
                .option(LineReader.Option.BRACKETED_PASTE, false)
                .build();

On git-bash the terminal type is xterm and uses ExternalTerminal. For unix, type is xterm-256color and uses PosixPtyTerminal.

I checked other threads but neither solution worked, maybe I missed something.
Is there any other way to remove those escape sequences?

[mattirn]

When you use custom streams I think you should create your terminal as

Terminal terminal = TerminalBuilder.builder()
                .streams(inputStream,outputStream)
                .size(new Size(160,50))
                .type(Terminal.TYPE_DUMB)
                .build();

[krzsal]

Thanks for the help, setting Terminal.TYPE_DUMB did the trick and escape sequences are no longer displayed. However a side effect appeared. Now the command is printed again in new line, e.g.

prompt> command
command
command_output

Is there any way to disable this echoing?

[mattirn]

Ok, dumb terminal is rather primitive to be used in interactive session. You might want to create a real terminal, see an example in ShellFactoryImpl.java#L119-L223.

[krzsal]

I tried to create terminal with same attributes/flags as the one that is created by cmd/powershell but the escape sequence characters are still printed. It looks like the different settings are applied depending of the os terminal from which application is started. E.g. starting application from cmd/powershell/2-click sets terminal type to null and the jline works perfect. However, starting from git-bash, sets terminal type to xterm and the problem with escape sequences appears. Also I tried to set terminal type to windows-vtp (this is used when using system streams) but then in both cases get escape character printed. I do not know if this is relevant but the output stream prints to javafx elements. I think that starting application from git-bash sets unix-like properties in the jvm from witch jline gets properties.

[mattirn]

If terminal type is not set when building terminal then TerminalBuilder will get type from environment variable TERM. In git-bash TERM default value is xterm and that's why TerminalBuilder builds for you terminal type xterm.

When you build terminal using custom streams and you do not have environment variable TERM (cmd/powershell/2-click) then I think TerminalBuilder will build terminal type ansi. You can print the terminal type to be sure

            System.out.println(terminal.getName() + ": " + terminal.getType());

When using git-bash/unix try to build your terminal as

Terminal terminal = TerminalBuilder.builder()
                .streams(inputStream,outputStream)
                .size(new Size(160,50))
                .type("ansi")
                .build();

[krzsal]

The "ansi" type solved all the problems, thanks a lot for help.

When you build terminal using custom streams and you do not have environment variable TERM (cmd/powershell/2-click) then I think TerminalBuilder will build terminal type ansi. You can print the terminal type to be sure

        System.out.println(terminal.getName() + ": " + terminal.getType());

FYI the terminal.getType() returns null and it uses org.jline.terminal.impl.ExternalTerminal. In all other cases the type was returned properly.