[luatex] Bug in tex.linebreak ?

[Frank Mittelbach]

you are proving my point aren't you?

> \setbox0\hbox{\input tufte }
> \directlua{
>      local n,t,head
>      head = tex.box[0].head
>      n, t = tex.linebreak(node.copy_list(head), {looseness=1})
>      print("1.1",t.looseness)
>      n, t = tex.linebreak(node.copy_list(head), {looseness=0})
>      print("1.2",t.looseness)
> }
> \directlua{
>      local n,t,head
>      head = tex.box[0].head
>      n, t = tex.linebreak(node.copy_list(head), {looseness=1,
> tolerance=4500, pretolerance=100, emergencystretch=655360 })
>      print("2.1",t.looseness)
>      n, t = tex.linebreak(node.copy_list(head), {looseness=0,
> tolerance=4500, pretolerance=100, emergencystretch=655360 })
>      print("2.2",t.looseness)
> }
> \tolerance4500 \pretolerance100 \emergencystretch10pt
> \directlua{
>      local n,t,head
>      head = tex.box[0].head
>      n, t = tex.linebreak(node.copy_list(head), {looseness=1})
>      print("3.1",t.looseness)
>      n, t = tex.linebreak(node.copy_list(head), {looseness=0})
>      print("3.2",t.looseness)
> }
>
> 1.1    0
> 1.2    0
> 2.1    1
> 2.2    1
> 3.1    1
> 3.2    1

1.2   2.2  and 3.2  should show "0"  given that we run the linebreaking 
with looseness zero but 2.1 and 3.1 still show "1"

and if you add t.prevgraf  you can see that it actually does do 
looseness correctly:

1.1	0	7
1.2	0	7
2.1	1	8
2.2	1	7
3.1	1	8
3.2	1	7

am I missing something? the first column reports wrong values

frank