Re: Minimum bison and flex versions

Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2022-09-02 15:08:01 -0400, Tom Lane wrote:
>> As fodder for discussion, here's a scraping of the currently-tested
>> versions. (This counts only animals running configure, ie not MSVC.
>> Also, my query looked back a few months, so some recently-dead
>> animals are still here.)

> All the other animals using bison < 3.0.2 are dead.

Uh, what?

longfin | 2022-09-02 16:09:42 | configure: using bison (GNU Bison) 2.3
sifaka | 2022-09-02 16:02:05 | configure: using bison (GNU Bison) 2.3
frogfish | 2022-08-21 17:59:26 | configure: using bison (GNU Bison) 2.5
lapwing | 2022-09-02 16:40:12 | configure: using bison (GNU Bison) 2.5
skate | 2022-09-02 07:27:10 | configure: using bison (GNU Bison) 2.5
snapper | 2022-09-02 13:38:22 | configure: using bison (GNU Bison) 2.5
prion | 2022-09-02 16:03:16 | configure: using bison (GNU Bison) 2.7
shelduck | 2022-09-02 06:42:13 | configure: using bison (GNU Bison) 2.7

I'm not sure why frogfish hasn't reported in for a few days, but these
others are certainly still live.

longfin and sifaka are using the Apple-provided copy of bison.
If we move the minimum version above 2.3, that will cause some
pain for all Mac-based developers. Maybe not much, because most
probably can get it from homebrew or macports, but some.

> 2.3 is the last bison version using GPLv2, so it's unlikely that apple will
> ever update. Given that I'm not sure how much we should feel beholden to
> support that, given that we'll eventually have to bite the bullet.

Seeing that they're au courant on flex (2.6.4), it certainly looks like
a license problem rather than that they just don't care about these tools
at all. Nonetheless, I want to see a pretty solid benefit from breaking
compatibility with 2.3, and I'm not convinced we're there yet.

> For flex, the minimum after prariedog's demise seems to be 2.5.35, with a
> decent population. Skimming the release notes [2] between 2.5.31 and 2.5.35
> doesn't show anything particularly interesting. But given that we don't have
> coverage and that 2.5.35 was released in 2008, it seems we could just update
> our requirements so that we have test coverage?

Yeah, I think setting the minimum to 2.5.35 is a no-brainer there.
(If memory serves, the only major difference between 2.5.33 and 2.5.35
was a security fix that LTS distros cherry-picked without changing
their version numbers, so that anything claiming to be 2.5.33 today
is probably effectively 2.5.35 anyway.) There aren't a huge number
of animals still on 2.5.35:

frogfish | 2022-08-21 17:59:26 | configure: using flex 2.5.35
hoverfly | 2022-09-02 16:02:01 | configure: using flex 2.5.35
lapwing | 2022-09-02 16:40:12 | configure: using flex 2.5.35
skate | 2022-09-02 07:27:10 | configure: using flex 2.5.35
snapper | 2022-09-02 13:38:22 | configure: using flex 2.5.35

but on the other hand I don't know that we'd gain anything by making
them update.

I'd be content for now to set the minimums at 2.3 and 2.5.35.

regards, tom lane