Marc Khouzam wrote:

> Hi,
> 
> I believe a small bug slipped in the refactoring of varobj_update
> interface from:
> http://sourceware.org/ml/gdb-patches/2008-05/msg00106.html
> 
> From what I see, varobj that are not in scope don't get flagged
> as changed, because nothing was being pushed on the result vector.
> The attached patch fixes this.
> 
> The MI part of the testsuite passed ok.
> I have an test to trigger the bug, if you care to see it.
> 
> Ok?
> 
> 2009-04-28  Marc Khouzam  <marc.khouzam@ericsson.com>
> 
> * varobj.c (varobj_update): Push an out-of-scope
> variable object on the result vector.
> 
> Index: gdb/varobj.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/varobj.c,v
> retrieving revision 1.126
> diff -u -r1.126 varobj.c
> --- gdb/varobj.c        10 Apr 2009 16:00:49 -0000      1.126
> +++ gdb/varobj.c        28 Apr 2009 19:49:24 -0000
> @@ -1188,7 +1188,7 @@
>        if (new == NULL)
>         r.status = VAROBJ_NOT_IN_SCOPE;
>  
> -      if (r.type_changed || r.changed)
> +      if (r.type_changed || r.changed || r.status ==
> VAROBJ_NOT_IN_SCOPE)
>         VEC_safe_push (varobj_update_result, result, &r);

I am afraid this patch is not right for two reasons:

1. A varobj that is not in scope will be always reported
as changed:

        (gdb)
        -var-update S
        ^done,changelist=[{name="S",in_scope="false",type_changed="false"}]
        (gdb)
        -var-update S
        ^done,changelist=[{name="S",in_scope="false",type_changed="false"}]
        (gdb)

This behaviour almost patches GDB 6.8 (it did not print 'type_changed'), but is
not right.

2. When a varobj enters the scope again, it won't be reported as changed:

        (gdb)
        s
        &"s\n"
        ^running
        *running,thread-id="1"
        (gdb)
        ~"foo () at a.c:7\n"
        ~"7\t    s.i = 10;\n"
        *stopped,....
        (gdb)
        -var-update S
        ^done,changelist=[]
        (gdb)


This does not match GDB 6.8 -- which continues to claim 'S' is out of scope. Both
the above, and GDB 6.8 are clearly in error.

I have checked in the below that makes -var-update bahave right in both cases. Let
me know if that works for you.

Thanks,
Volodya