Re: [RFC] delete gdb.cp/ambiguous.exp ?

[Doug Evans <dje at google dot com>]

On Tue, Aug 19, 2014 at 10:50 AM, Pedro Alves <palves@redhat.com> wrote:
> On 08/19/2014 06:24 PM, Doug Evans wrote:
>
>>> Actually enabling the test (removing the skip, and adding
>>> nowarnings), we see that indeed GDB outputs no warning:
>>
>> But given the early exit the test itself is never run.
>
> As I said, I removed that.  ;-)

I know (I thought that was obvious).
If you want to actually check in its removal, we can have that discussion.

>> And it's been this way since at least 2003 (commit 4d9eda44f), and
>> longer (that commit just changed the style of the gcc test)!
>
> Yeah, this probably came in in the big HP merge, much
> earlier than that.  There was once a gdb.hp/ambiguous.exp, even, and
> this probably got copied from that.
> There was once a big
> everything-goes-we-dont-have-time-to-clean-things-up-before-accepting HP
> import/contribution, and bits may be skipped on GCC just because the
> HP folks at the time didn't want to deal with it in their local fork.
>
>> I'm all for filing a bug and recording the test in the bug report.
>> I'm even ok with keeping the test as is.
>> The high order bit for me is exploring what the community wishes be
>> done with this kind of "dead code".
>
> You're asking for a generic opinion, of the abstract "community",
> while I think "case by case" generally applies.  ;-)

I'm asking people for their opinion on this case (and cases like it).
If I call them a "community", which is what gdb@ and gdb-patches@ is
to me, I don't see the problem.

Removal of dead code is, in my experience here, *rarely* a case by
case decision.
[each case may have minor details that are different, but the high
order bit is generally DELETE IT :-)]
And yet this is a little different than an #if 0 in code, so I'm asking.
We certainly want to document this issue in some way, but if we're
just going to leave the test as is, not being run, and yet have to
disable it for new compilers as they come along, then I think there's
value in documenting the issue in a different way (e.g., bug reports
are fine for this sort of thing).

> My inclination for
> tests is to first check whether there's something salvageable.  If
> someone wrote the test, it was probably important enough.  If it's indeed
> "dead code", then of I'd go for just removing it.  I looked, and it seemed
> to me that the test actually covers an aspect of printing that we don't
> cover elsewhere, and actually reveals a bug.
> So IMO, in this particular case, we should keep the test, remove the gcc check,
> modernize and KFAIL it , and then have the bug fixed (if people agree it's
> a bug).  I'm of course not suggesting you do that all of yourself, but
> since you asked, that's what I'd prefer see done in this case.

This is feedback I can work with.  Thanks.

Going forward, as we discover bugs, are people ok with checking in a
KFAIL'd test for a bug before the bug is fixed?  "Just fix the bug."
is the canonical response.  And yet there are often higher priorities.
How do we document the bug's existence so that it's not forgotten
until someone has time to fix it?  File a bug report, of course.
Well, I file bug reports all the time, I certainly don't have time to
fix all of them instead of filing the bug report.  And if in
reproducing the bug I'm 80% of the way there in writing the test, is
it ok to at least finish and check in that part, even if I don't have
time to fix the bug?

Or, instead of allowing that, should we just "grandfather in", so to
speak, all existing disabled tests, not allow new KFAIL'd ones, and
migrate these existing tests to KFAIL if we don't have time to fix the
bug?