Postgres 10 support

[PVince81]

From #29997.

• update to dbal v2.8 on master
• setup Drone target for Postgres 10
• fix all found issues, if any

[ownclouders]

GitMate.io thinks possibly related issues are #29625 (Drop sqlite support), #9889 (Setup for Postgres), #31352 (Update to 10.0.8 failed; Possible Postgres 10 Doctrine regression), #15124 (MPO support), and #8269 (Gravatar support?).

[PVince81]

we already have the drone target https://github.com/owncloud/core/blob/master/.drone.yml#L622, closing

[gramakri]

@PVince81 Will Postgres 10 be supported in oc 10.1.0 or just oc 11? When can we expect oc 11 (I don't see a beta even).

[phil-davis]

Note: https://github.com/doctrine/dbal/releases/tag/v2.6.0
"PHP 7.1.0 is the minimum supported PHP version"

core stable10 is dropping PHP 5.6 support, but for now keeps support for PHP 7.0. So composer in stable10 finds doctrine/dbal v2.5.13 - it can't yet use doctrine/dbal v2.6.0 or above.

In particular, we can't get to doctrine/dbal v2.8.0 in stable10 just yet :(

[phil-davis]

Note:

• PR Bump doctrine/dbal from 2.6.3 to 2.7.1 #31059 was also an essential part of Postgres 10 support.
• PR drop php 7.0 [DO NOT MERGE YET] #35786 has the backports needed for stable10. It can be implemented once "drop PHP 7.0" is allowed in stable10

[phil-davis]

Now that core master is the old core stable10 we no longer have the PostgreSQL 10 support code sitting in core master. It is now waiting in PR #35962

PostgreSQL 10 needs minimum PHP 7.1. So getting this into a release is blocked until we can drop PHP 7.0.

Reopening the issue so it gains visibility again.

[phil-davis]

Code for this is in the commits waiting in #36289 and #36290

[phil-davis]

PR #36498 runs the full test suite with postgres:10.3 as the database and passes.

[phil-davis]

PR #36290 was merged. This is now in master for release in 10.4