Re: deleting next newline character in java 21 (linux)

The problem is a changed BreakIterator implementation [1]

- before openjdk 20 it was sun.util.locale.provider.RuleBasedBreakIterator
- after, it is sun.util.locale.provider.BreakIteratorProviderImpl$GraphemeBreakIterator

RuleBasedBreakIterator.following() returns DONE when we are at the last character of the line (next character is new line)
GraphemeBreakIterator.following() returns the current offset when we are at the last character of the line.

Here is a patch to fix it on openjdk:

diff --git a/org/gjt/sp/jedit/textarea/TextArea.java b/org/gjt/sp/jedit/textarea/TextArea.java
index 9ce126e49..13214008b 100644
--- a/org/gjt/sp/jedit/textarea/TextArea.java
+++ b/org/gjt/sp/jedit/textarea/TextArea.java
@@ -6314,7 +6314,7 @@ loop:             for(int i = lineNo - 1; i >= 0; i--)
                {
                        int following = charBreaker.following(offset -
                                        index0Offset);
-                       if (following == BreakIterator.DONE)
+                       if (following == BreakIterator.DONE || (Runtime.version().feature() >= 20 && following == offset - index0Offset))
                        {
                                // This means a end of line. Then it is
                                // safe to assume 1 code unit is a character.


I don't know the code in TextArea and I can't vouch for it working correctly with characters above BMP.
If k_satoda is still around, I would really appreciate the help.

Also I hope the condition on Runtime.version().feature() is inlined by the JIT compiler but a better solution should be considered.

Please anybody help on this: I think it should be fixed for jEdit 5.7 release...

Cheers,

[1] https://bugs.openjdk.org/browse/JDK-8291660

Le Fri, 2 Jun 2023 15:15:10 -0600,
Dale Anson <[email protected]> a écrit :

> I tried the KeyEventDemo from Oracle. I made a minor adjustment to use
> a text area instead of a text field in the demo to be able to test
> delete at the end of a line. The delete key in the demo works fine.
> I've attached the demo code if you want to try it out.
> 
> I guess this means the problem is in jEdit, not in Java.
> 
> On Fri, Jun 2, 2023 at 2:51 PM Dale Anson <[email protected]> wrote:
> >
> > I'm not finding anything by googling about this. I did find that if
> > I press Ctrl-Delete at the end of the line that it works like I
> > would expect Delete by itself to work. It seems the delete key works
> > correctly everywhere except at the end of a line. I'm testing with
> > Java 20.
> >
> > On Fri, Jun 2, 2023 at 9:48 AM Alan Ezust <[email protected]>
> > wrote:  
> > >
> > > I can confirm the same problem exists in openJDK 20 (linux). Do
> > > we work around it in jEdit or do we try to report it as a bug in
> > > openjdk, I wonder?
> > >
> > > On Wed, May 31, 2023 at 11:20 AM Alan Ezust
> > > <[email protected]> wrote:  
> > >>
> > >> I just tried jEdit with java21 and now the "delete" character no
> > >> longer works if I am at the end of the line - i expect it to
> > >> delete the newline and it just doesn't. switching to java 19
> > >> makes the problem go away. 
> > > --
> > > -----------------------------------------------
> > > jEdit Developers' List
> > > [email protected]
> > > https://lists.sourceforge.net/lists/listinfo/jedit-devel  



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