[Rd] [FORGED] src/modules/X11/devX11.c, can we remove "#if BUG" yet

[Paul Murrell]

Hi

Sorry, I can't offer an explanation for the commented-out line.
However, regarding your final question of avoiding the R-core 
bottleneck, you do have the option of creating a third-party graphics 
device package.  See, for example, the 'tikzDevice' and 'svglite' 
packages on CRAN.  Does that provide you with a way forward ?

Paul

On 20/04/2019 5:27 p.m., frederik using ofb.net wrote:
> Dear R Devel,
>
> I know that someone put this line in src/modules/X11/devX11.c:2824 for
> a reason, because commenting it out causes R to miss an important
> ConfigureNotify event in my window manager. The result is that plots
> are initially drawn off the window borders, unreadable.
>
>     R_ProcessX11Events((void*) NULL);
>
> Unfortunately for me, this line is commented in the standard release
> of R, it has "#if BUG ... #endif" around it.
>
> I guess it is also unfortunate for anyone who uses the same window
> manager as I do, namely i3, which I think is pretty popular among Unix
> power users these days; not to mention other full-screen window
> managers which probably exhibit the same bug in R.
>
> Maybe everyone on the Core team uses twm as their window manager? Or
> RStudio on Windows? Which would be sad because then we're not
> representing an important user demographic, namely those who prefer
> software which is modern and powerful, yet simple to understand and
> modify; fully configurable and interoperable and so on.
>
> I first reported this bug 3 years ago. In doing research for my bug
> report, I found that the line was commented out by Peter Dalgaard in
> 2001 with the explanation "X11 segfault fix - I hope".
>
> I don't know what the way forward is. Obviously the Core Team has
> reason to say, "look, this isn't very important, it's been broken
> since 2001, maybe fixing it will cause the undocumented segfault bug
> to reappear, clearly no one here uses your window manager". Do I have
> to submit a correctness proof for the proposed change? What do I do?
>
> https://bugs.r-project.org/bugzilla/show_bug.cgi?id=16702
>
> As mentioned in my bug report, I checked using gdb that
> ConfigureNotify is indeed being received by the call to
> R_ProcessX11Events() when it is uncommented. I haven't experienced any
> segfaults.
>
> It's good that Peter left evidence that "R_ProcessX11Events" was being
> called 18 years ago from X11DeviceDriver(). If he had deleted the
> line, rather than commenting it, then discovering the reason for the
> window rendering bug would have been much harder for me.
>
> However, the downside is that now it is not just a matter of inserting
> the line where it belongs; I also feel a bit like I have to explain
> why it was initially removed. But although I've given it some thought,
> I still have no idea.
>
> Somewhat tangentially, I am wondering if there is some way that we
> could make the development of R's graphics code proceed at a faster
> rate, for example by pulling it out into a separate module, so that
> people could offer alternative implementations via CRAN etc., rather
> than having R Core be the bottleneck. Would this make sense? Has it
> already been done?
>
> Thank you,
>
> Frederick
>
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-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul using stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/