TerminalBuilder.system(false).dumb(true) does not give a DumbTerminal. Is this working as intended?

[dattasid]

Jline version 3.26.1
JDK : 11.0.23

Java code:

import org.jline.terminal.Terminal;                                                  
import org.jline.terminal.TerminalBuilder;                                           
                                                                                     
public class jt {                                                                    
  public static void main(String[] args) throws Exception                            
    {                                                                                
      TerminalBuilder builder = TerminalBuilder.builder()                            
        .type("dumb")                                                                
        .dumb(true)                                                                  
        .system(false)                                                               
        .streams(System.in, System.out);                                             
      System.out.println(builder.build());                                           
    }                                                                                
}

Execute:

$ java -cp ./jline3-jline-parent-3.26.1/jline/target/jline-3.26.1.jar:. --add-opens java.base/java.io=ALL-UNNAMED jt
org.jline.terminal.impl.PosixPtyTerminal@4b1c1ea0

Note: I will get a DumbTerminal if I set system(true), but then I get occasional terminal codes in the output.

[gnodet]

The dumb, jna, jansi, jni, exec and ffm methods on the TerminalBuilder are meant to enable/disable a given provider, not force its usage. If you want to force the use of a given provider, you can use builder.provider("jni") for example.
The dumb provider can only create a system terminal, so if you specify system(false), the dumb provider won't be used.

The ansi sequences appearing with a dumb terminal should be fixed, so do not hesitate to raise issues for those.

What's your use case exactly ? You usually don't really always want a dumb terminal...

[dattasid]

My CLI can be used in interactive mode or be fed a file cli < in > out .

When I see that System.console() == null, I assume that the cli is reading from a file. So I try to use a dumb terminal. This is because when I started using JLine 3, other terminals would print console codes in the output file.

I also had to set terminal.setSize(10000,10000) so that even dumb terminal does not output control codes when reaching the end of the supposed screen. Now that dumb terminal is always a system terminal, it is now ignoring the size I set. I am seeing console codes in the output file.

Is there a terminal which knows if we are reading from and/or writing to a file, and disables all control characters ?

PS: As a separate issue, I see that JLine behaves badly when size is set to (0,0). This is possible if stty is set up badly and returns lines 0 columns 0. JLine should assume sane values (maybe 24,80) when it sees invalid values like (0,0) . I think the code is ExecPty.getSize(), but I havent tested a fix.

I also see some issues with JLine on serial port like ttyS0 , Do you have a system where you can test ttyS0 ?

[gnodet]

My CLI can be used in interactive mode or be fed a file cli < in > out .

When I see that System.console() == null, I assume that the cli is reading from a file. So I try to use a dumb terminal. This is because when I started using JLine 3, other terminals would print console codes in the output file.

The TerminalBuilder is supposed to handle that. It will create a real terminal if the input stream is connected to the terminal and if either the output or error stream is connected. On output, you can force the selection by configuring

jline3/terminal/src/main/java/org/jline/terminal/TerminalBuilder.java

Line 205 in f370265

public TerminalBuilder systemOutput(SystemOutput systemOutput) {

I also had to set terminal.setSize(10000,10000) so that even dumb terminal does not output control codes when reaching the end of the supposed screen. Now that dumb terminal is always a system terminal, it is now ignoring the size I set. I am seeing console codes in the output file.

Is there a terminal which knows if we are reading from and/or writing to a file, and disables all control characters ?

The dumb terminal is supposed to. Anything else is a bug.

PS: As a separate issue, I see that JLine behaves badly when size is set to (0,0). This is possible if stty is set up badly and returns lines 0 columns 0. JLine should assume sane values (maybe 24,80) when it sees invalid values like (0,0) . I think the code is ExecPty.getSize(), but I havent tested a fix.

Ok, that may need a fix too.

I also see some issues with JLine on serial port like ttyS0 , Do you have a system where you can test ttyS0 ?

Not sure how I could do that...