Allow nested transactions when global transaction is in place

[MZanggl]

Proposed changes

The fix addresses the following issue adonisjs/vow#22.
I also had issues on my own, where I would get Error: Test timeout, ensure "done()" is called; if returning a Promise, ensure it resolves. in some places.

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

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Further comments

Ideally beginTransaction would just be

if (this._globalTrx) {
   return this._globalTrx.transaction()
}

return this.knex.transaction()

but I think the knex version first has to be updated to include this fix here knex/knex#3393

[coveralls]

Coverage decreased (-78.6%) to 17.926% when pulling ce10f16 on MZanggl:bugfix/savepoints into 6cd666d on adonisjs:develop.

[davebot9000]

May be off topic, but why are we catching without rejecting? Not ever rejecting just causes the promise to be left pending indefinitely. In a web app this can cause a server to crash if enough transactions fail (e.g. database is overloaded). A preferable outcome would be to reject so that the server can handle the result gracefully.

[MZanggl]

Seems the builds are failing for reasons outside of my change. I remember the first time they were all successful. I also tried retriggering it :/

$ npm install sqlite3 --save

Cannot find module '/home/travis/build/adonisjs/adonis-lucid/node_modules/sqlite3/lib/binding/node-v79-linux-x64/node_sqlite3.node'

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.