GNU bug report logs - #13400
23.4; overlapping process filter calls

Previous Next

Full log

View this message in rfc822 format

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Hendrik Tews <hendrik <at> askra.de>
Cc: 13400 <at> debbugs.gnu.org, Noam Postavsky <npostavs <at> gmail.com>
Subject: bug#13400: 23.4; overlapping process filter calls
Date: Tue, 06 Aug 2019 03:40:44 -0400

> complete. If the programmer cannot rely on the documentation to
> be complete here, he or she has no other choice than to assume
> that output can arrive anywhere and he/she _is_ plagued with the
> usual parallel programming problems.

While I largely agree with your points, I'll mention that we *are*
plagued, because lots of functions may (in some cases) end up calling
a blocking operation.  E.g. any call to a file function can block if the
file happens to be handled by Tramp, so any call to a function which
(transitively) calls a file function can itself block.

> It is about a few words making the documentation more precise,
> potentially saving somebody a painful debugging session of
> several hours - similar to what I went through in 2013. Back
> then, I was lucky because clearing the disk caches was enough to
> reproduce the problem. Today with SSD's it is probably much
> harder...

I think preventing recursive filter invocations (by default) would be
much better than warning the programmer about that odd possibility.


        Stefan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.