Fix Travis builds (using stages)

[octonato]

No description provided.

[marcospereira]

Why use stages here? It is way more verbose than the build matrix. I would prefer to remove the bash scripts instead since they aren't adding much value here. I suggest remove them and have:

script:
  - sbt ++TRAVIS_SCALA_VERSION test scalafmtCheckAll ...

That way, we won't bother with travis_terminate as well.

[dwijnand]

That way, we won't bother with travis_terminate as well.

Only if it's a oneliner.

[octonato]

Why use stages here?

For a few reasons, first, the three scripts are being run all together, one after the other, on a single build. This gives us less visibility on what is breaking or not.

Second, adding the validation on the first stage is interesting because we can do a quick sanity check before starting running more heavy jobs. We are doing so for Play and Lagom and is paying off.

I agree that we don't need the scripts and we could inline them. Actually, I realise now that the reason why we had this travis_terminate thing was that we were running all three scripts in one single job.

Another reason for using stages is that we can select some stages to run on PRs and others on merges or cron (although there is no cron for twirl)

Now, I personally don't like the matrix in Travis. I find stages with explicitly env variables more obvious. At least I can immediately see what is going to happen.

[marcospereira]

Thanks for the explanation regarding the use of stages, @renatocaval.

This LGTM.