Remove some or all Travis CI jobs

[PhysSong]

Recently, Travis CI announced their new pricing model. Due to some abusers, they are making some changes which affects our CI jobs.
Some devs talked on Discord to work around this change.

job	status
ShellCheck	Covered by CircleCI but with silghtly different script
Linux x86_64, GCC	Covered by CircleCI
Debian x86_64, GCC	Travis only
Debian i386, GCC	Travis only
Debian i386, Clang	Travis only
macOS x86_64, AppleClang	Covered by CircleCI

Things to discuss:

• Do we need to keep jobs covered by CircleCI?
• Is it worth running Debian builds on our side? Can we remove some of those jobs? (CC @jasp00)

Relevant discussion on Discord

liushuyu said:
macOS build will be 50 credits per minute from now on
https://blog.travis-ci.com/2020-11-02-travis-ci-new-billing
OSS projects will get 10k credits at the beginning (not replenish-able) and when runs out, you need to contact support to get more
At this rate, our credits will run out in ~4 builds
(Unless someone want to negotiate with the support or warm-up their credit card)

tresf said:

Unless someone want to negotiate with the support or warm-up their credit card

Most of our stuff is over on Circle-CI now, but if the pricing isn't too bad, we can consider it.

liushuyu said:
USD$15 for 25k credits, macOS build costs 50 credits per minute. Timeout once = 2.5k credits spent
That's $15 for 10 commits
I don't think this is a good deal at all

PhysSong said:
I'd say let's remove the Travis macOS builds.

Dom said:
My understanding of that Travis blog post is that the OSS credit system affects all build platforms, not just macOS. Even without macOS builds, we still use about an hour and a half of build time per commit. With Linux builds at 10 credits/minute, that's still only 11 commits before we have to go ask for more.

liushuyu said:
Correct
Also, I am curious why we are still having Travis CI running when we already got Circle CI?

PhysSong said:
No ideas. There are some jobs only running on Travis, but I think we can move to Circle if desired.
Debian SID .deb builds are not in Circle, but Why are we keeping them?
i386, Clang builds might be worth keeping, though.
@jasp00 has added them, so might be worth asking him on a GitHub issue first.

Summary of the discussion:

• Keep using Travis will require contacting support whenever we run out of credits.
• macOS builds will consume a lot of credits, but the consumption is not small even without it.
• We may consider removing some jobs already covered by CircleCI.

[jasp00]

Is it worth running Debian builds on our side?

One reason for these builds was to help Debian maintenance, which was valid when I had some weight in this maintenance. So you should ask @sebastinas about this issue.

[sebastinas]

As long as one Linux build is tested, this should be fine. Paging @snd1 who is probably more interested in LMMS than I am.

[PhysSong]

We don't have many days left:

Please be aware travis-ci.org will be shutting down in several weeks, with all accounts migrating to travis-ci.com. Please stay tuned here for more information.

Once the migration finishes, the credit starts to be used. So I think it's time to remove them.

[PhysSong]

Since June 15th, 2021, travis-ci.org is now in read-only state. travis-ci.com builds are not enabled at this moment.