RFR: 8362116: System.in.read() etc. don't accept input once immediate Ctrl+D pressed in JShell

[Jan Lahoda]

On Mon, 14 Jul 2025 12:48:27 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

> When in JShell, doing:
> 
> jshell> IO.readln();
> //Ctrl-D
> $1 ==> null
> 
> jshell> IO.readln()
> $2 ==> null //no input allowed
> 
> 
> Where relying input from the main process to the remote/agent process, need to propagate `-1` as `-1` without close, which is what this PR is attempting to do.

src/jdk.jshell/share/classes/jdk/internal/jshell/tool/ConsoleIOContext.java line 1438:

> 1436:         public Attributes enterRawMode() {
> 1437:             Attributes res = super.enterRawMode();
> 1438:             res.setControlChar(ControlChar.VEOF, 4);

This is to correctly recognize `4`/Ctrl-D in the input in tests. Note this terminal is supposed to only be used by tests.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26292#discussion_r2204860401