Tentative high-level plans for 7.10.1

[John Lato]

Speaking as a user, I think Johan's concern is well-founded.  For us,
ghc-7.8.3 was the first of the 7.8 line that was really usable in
production, due to #8960 and other bugs.  Sure, that can be worked around
in user code, but it takes some time for developers to locate the issues,
track down the bug, and implement the workaround.  And even 7.8.3 has some
bugs that cause minor annoyances (either ugly workarounds or intermittent
build failures that I haven't had the time to debug); it's definitely not
solid.  Similarly, 7.6.3 was the first 7.6 release that we were able to use
in production.  I'm particularly concerned about ghc-7.10 as the AMP means
there will be significant lag in identifying new bugs (since it'll take
time to update codebases for that major change).

For the curious, within the past few days we've seen all the following,
some multiple times, all so far intermittent:

> ghc: panic! (the 'impossible' happened)
> (GHC version 7.8.3.0 for x86_64-unknown-linux):
>     kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d}

> ByteCodeLink.lookupCE
> During interactive linking, GHCi couldn't find the following symbol:
>     some_mangled_name_closure

> ghc: mmap 0 bytes at (nil): Invalid Argument

> internal error: scavenge_one: strange object 2022017865

Some of these I've mapped to likely ghc issues, and some are fixed in HEAD,
but so far I haven't had an opportunity to put together reproducible test
cases.  And that's just bugs that we haven't triaged yet, there are several
more for which workarounds are in place.

John L.

On Sat, Oct 4, 2014 at 2:54 PM, Johan Tibell <johan.tibell at gmail.com> wrote:

> On Fri, Oct 3, 2014 at 11:35 PM, Austin Seipp <austin at well-typed.com>
> wrote:
>
>>  - Cull and probably remove the 7.8.4 milestone.
>>    - Simply not enough time to address almost any of the tickets
>>      in any reasonable timeframe before 7.10.1, while also shipping them.
>>    - Only one, probably workarouadble, not game-changing
>>      bug (#9303) marked for 7.8.4.
>>    - No particular pressure on any outstanding bugs to release
>> immediately.
>>    - ANY release would be extremely unlikely, but if so, only
>>      backed by the most critical of bugs.
>>    - We will move everything in 7.8.4 milestone to 7.10.1 milestone.
>>      - To accurately catalogue what was fixed.
>>      - To eliminate confusion.
>>
>
> #8960 looks rather serious and potentially makes all of 7.8 a no-go for
> some users. I'm worried that we're (in general) pushing too many bug fixes
> towards future major versions. Since major versions tend to add new bugs,
> we risk getting into a situation where no major release is really solid.
>
>
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