Increase OTP 24 readiness + move to OTP 20 min.

[paulo-ferraz-oliveira]

What this pulls in:

• Squash a warning on OTP 24 (master) uwiger/parse_trans#41
• Handle annotations and locations better uwiger/parse_trans#42
• Update Travis OTP vsns (21 and later), fix try/catch and some edoc uwiger/parse_trans#43

After I saw that a bump was required, I decided to adapt to min. OTP 21(now) 20

• don't merge until you decide to up min. to OTP 20
• potentially tweak TARGET_ERLANG_VERSION
• bump erlware_commons (after something like Fixes for dialyzer erlware/erlware_commons#152 happens)
• tweak bootstrap to adapt to these changes too

[paulo-ferraz-oliveira]

Yeah, so this seems to be OTP-21 min. Probably it could stay open until you decide to bump min. on your end too.

[ferd]

We can't do this.

We usually deprecate the version when we have the official new release to go with, and then get rid of the old stuff when there's no way around. If we can't keep OTP-20 going, then we're more likely to just not upgrade the dependency and live with warnings.

We would probably need to revisit the backwards compatibility policy to do otherwise, if we can avoid doing that for a while it would probably be good to do so, otherwise our users might find themselves with far less generous support windows than expected. If we plan to close the window and clamp it down to a lower range, we should probably give significant heads up.

[paulo-ferraz-oliveira]

We can't do this.

All of it, or parts of it? (I mean, I'm preparing for when you want to bump; it doesn't have to be now). 👍

We usually deprecate the version when we have the official new release to go with, and then get rid of the old stuff when there's no way around.

Oh, OK. We can keep adding -ifdef, I guess, if you're OK with it. I just imagined that when OTP 24 came out you might want to bump to min. OTP 21 (I was probably hopeful for recent discussions/exchanges we'd had and interpreted wrong).

If we can't keep OTP-20 going, then we're more likely to just not upgrade the dependency and live with warnings.

Sure. I'm OK with that.

We would probably need to revisit the backwards compatibility policy to do otherwise, if we can avoid doing that for a while it would probably be good to do so, otherwise our users might find themselves with far less generous support windows than expected. If we plan to close the window and clamp it down to a lower range, we should probably give significant heads up.

I'd always thought (might be wrong) that support as current-5, which would put min. at 20 once 24 comes out. If that's true not all of what was done will be trashed. 😄

Shall I put this at (prepare for) a min. 20 level, then?

[ferd]

Oh wait yeah, maybe we just didn't deprecate around last bump? If we didn't get rid of 19 when we started supporting 23 because we were opportunistic then we for sure should feel free to keep the same current-5. So this could be mergeable once OTP-24 drops, and then we narrow our window to what's supportable in -5.

That would be a huge quality of life improvement. Do note that we might be able to clean stuff up in bootstrap as well.

[paulo-ferraz-oliveira]

Yeah, I noticed bootstrap, but kinda stayed away from it 😄 I'll add a task to the description at the top.

If we drop OTP 20, that'll be current -4, so 21, 22, 23, 24. Which is the reason for my former question "Shall I put this at (prepare for) a min. 20 level, then?".

[ferd]

Yeah OTP-20 minimum makes the most sense here. We're likely to ship pre-built artifacts with OTP-21 regardless though, and leave it to people on OTP-20 to build on their own in order to get the broader coverage for users in what we ship.

[paulo-ferraz-oliveira]

I've pushed "min. 20" (it was mostly reverting stuff) + bootstrap updates.

[paulo-ferraz-oliveira]

Squash-rebased and force-pushed.

[paulo-ferraz-oliveira]

We might also want to consider TARGET_ERLANG_VERSION in the hex_core vendoring flow.
Also, erlware_commons calls :get_stacktrace() (which is deprecated in OTP 24, too).

[paulo-ferraz-oliveira]

I've squashed and force-pushed a change to handle "potentially tweak TARGET_ERLANG_VERSION" (was 19; is 20).

[ferd]

Sounds good. I'll merge this once OTP-24 drops, prior to that I won't deprecate versions officially.

[paulo-ferraz-oliveira]

Sure, only needs erlware/erlware_commons#152 to be merged and tagged, IMO.

[ferd]

Looking to bump erlware_commons in #2550 -- seeing if I can bump certifi in a way that gets rid of parse_trans at the same time.

[paulo-ferraz-oliveira]

I'm rebasing this branch on top of master.