Tentative high-level plans for 7.10.1

[Simon Peyton Jones]

Thanks for this debate.  (And thank you Austin for provoking it by articulating a medium term plan.)

Our intent has always been that that the latest version on each branch is solid.  There have been one or two occasions when we have knowingly abandoned a dodgy release branch entirely, but not many.

So I think the major trick we are missing is this:
 
   We don't know what the show-stopping bugs on a branch are

For example, here are three responses to Austin's message:

|  The only potential issue here is that not a single 7.8 release will be
|  able to bootstrap LLVM-only targets due to #9439. I'm not sure how

| 8960 looks rather serious and potentially makes all of 7.8 a no-go 
| for some users. 

|  We continue to use 7.2, at least partly because all newer versions of
|  ghc have had significant bugs that affect us

That's not good. Austin's message said about 7.8.4 "No particular pressure on any outstanding bugs to release immediately". There are several dozen tickets queued up on 7.8.4 (see here https://ghc.haskell.org/trac/ghc/wiki/Status/GHC-7.8.4), but 95% of them are "nice to have".  

So clearly the message is not getting through.  


My conclusion

 * I think we (collectively!) should make a serious attempt to fix show-stopping 
   bugs on a major release branch.  (I agree that upgrading to the next major
   release often simply brings in a new wave of bugs because of GHC's
   rapid development culture.)

 * We can only possibly do this if 
   a) we can distinguish "show-stopping" from "nice to have"
   b) we get some help (thank you John Lato for implicitly offering)

I would define a "show-stopping" bug as one that simply prevents you from using the release altogether, or imposes a very large cost at the user end.

For mechanism I suggest this.  On the 7.8.4 status page (or in general, on the release branch page you want to influence), create a section "Show stoppers" with a list of the show-stopping bugs, including some English-language text saying who cares so much and why.  (Yes I know that it might be there in the ticket, but the impact is much greater if there is an explicit list of two or three personal statements up front.)

Concerning 7.8.4 itself, I think we could review the decision to abandon it, in the light of new information.  We might, for example, fix show-stoppers, include fixes that are easy to apply, and not-include other fixes that are harder.

Opinions?  I'm not making a ruling here!

Simon

|  -----Original Message-----
|  From: ghc-devs [mailto:ghc-devs-bounces at haskell.org] On Behalf Of Ben
|  Gamari
|  Sent: 04 October 2014 04:52
|  To: Austin Seipp; ghc-devs at haskell.org
|  Cc: Simon Marlow
|  Subject: Re: Tentative high-level plans for 7.10.1
|  
|  Austin Seipp <austin at well-typed.com> writes:
|  
|  snip.
|  
|  >
|  > We do not believe we will ship a 7.8.4 at all, contrary to what you
|  > may have seen on Trac - we never decided definitively, but there is
|  > likely not enough time. Over the next few days, I will remove the
|  > defunct 7.8.4 milestone, and re-triage the assigned tickets.
|  >
|  The only potential issue here is that not a single 7.8 release will be
|  able to bootstrap LLVM-only targets due to #9439. I'm not sure how
|  much of an issue this will be in practice but there should probably be
|  some discussion with packagers to ensure that 7.8 is skipped on
|  affected platforms lest users be stuck with no functional stage 0
|  compiler.
|  
|  Cheers,
|  
|  - Ben