RFR: 8330998: System.console() writes to stderr when stdout is redirected [v2]

[Bernd]

On Mon, 29 Apr 2024 14:56:23 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

>> Consider code like:
>> 
>> public class ConsoleTest {
>>     public static void main(String... args) {
>>         System.console().printf("Hello!");
>>     }
>> }
>> 
>> 
>> When run as:
>> 
>> $ java ConsoleTest.java >/dev/null
>> 
>> 
>> it prints `Hello!` to stderr, instead of to stdout (where it would be redirected).
>> 
>> The proposed fix is to simply force the use of stdout. Sadly, this cannot be done solely using JLine configuration, we actually need to change the JLine's code for that.
>> 
>> The most tricky part is a test. There are two sub-tests, one effectively testing a case where all of stdin/out/err are redirected, the other is attempting to test the case where stdin is attached to a terminal, while stdout is redirected. The second sub-test using a native functions to create a pty and to attach to it, and should run in a separate VM, as it leaves the VM attached to the terminal.
>
> Jan Lahoda has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:
> 
>  - Merge branch 'master' into JDK-8330998
>  - Fixing test.
>  - Attempting to stabilize the test.
>  - Improving test to really test the redirect while stdin is connected to a terminal.
>  - Fixing typo.
>  - 8330998: System.console() writes to stderr when stdout is redirected

I think it's a feature when System.console() actually writes to the tty if stdout is redirected. After all it's not System.out. Of course the question is if it should write to stderr or /dev/tty like mechanism..

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PR Comment: https://git.openjdk.org/jdk/pull/18996#issuecomment-2083542510