Windows release quality

Phyx lonetiger at
Tue Mar 19 18:52:40 UTC 2019

Hi Andreas,

GHC 8.6.4 not supporting profiling libs was the first thing mentioned in
the release email

 - A regression resulting in segmentation faults on Windows introduced
   by the fix for #16071 backported in 8.6.3. This fix has been reverted,
   meaning that 8.6.4 is once again susceptible to #16071. #16071 will
   be fixed in GHC 8.8.1.

It was also stated that it would be back in 8.8.1.  At this point there was
no way to get profiling libs
on 8.6.x without a major backport of linker changes from master.  The
choice was made to revert the
change and release 8.6.4 without profiling libraries because of a stack
allocation bug that was dormant for
years but completely killed the 32 bit distribution. That said the
changelog linked to the wrong issue, the second
two should have been #15934 but that's not hard to figure out by looking at
the ticket.

This was not an oversight, both the choice to release GHC 8.6.4 without
profiling libs (which really to the average user is not mission critical)
and the fact to release 8.6.4 at all were thought out decisions. It could
have been communicated better yes.

That 8.6.3 wasn't removed I don't know. I pulled it from chocolatey at

8.6 is more production ready than 8.4 was, it just doesn't support
profiling libs for a while till 8.8 yes.


On Tue, Mar 19, 2019 at 5:57 PM Andreas Klebinger <klebinger.andreas at>

> Hello Devs,
> After running into #16408 today I realized there is as of yet no released
> bindist
> of the 8.6 series which I would consider stable for windows.
> GHC 8.6.1 and 8.6.2 had a series of critical bugs which applied to
> multiple platforms:
> GHC 8.6.3 loops forever if compiling certain code using TH on windows.
> This affects some very popular hackage packages: (#16057)
> <>
> GHC 8.6.4 (marked stable) currently ships without profiling libraries,
> making profiling impossible.
> Being stuck with 8.4 is one thing, and if properly communicated not too
> bad.
> But it requires work to even find out about these (major) issues and to
> discover that 8.6 is NOT production ready for windows.
> We offered the broken 8.6.3 as stable for weeks without any indication
> that it was broken.
> We still serve GHC 8.6.4 as stable without any hint about the missing
> profiling libraries.
> I can't offer solutions in this case but I feel like something about the
> release management has to change if .
> Having to check the GHC bugtracker to find out if the current stable
> release is actually stable is just not sustainable.
> _______________________________________________
> ghc-devs mailing list
> ghc-devs at
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