Schema diff fails with MariaDB 10.2

[m-vo]

I upgraded to MariaDB 10.2.12 (10.2.12-MariaDB-10.2.12+maria~xenial) on my dev machine and noticed that now the schema diff stopped working properly (contao bundles 4.5.1, doctrine/dbal 2.6.3).

I haven't had time to investigate further but here is what I am seeing: There are lots of entries that request to alter tables (even without the tables existing) and - if existing - columns.

This is what's happening to a new install:

@leofeyer I noticed that you referred to the same or a similar problem here but I'm not sure if there was a solution.

Also there seems to be a related issue in the community forum.

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By the way: Having innodb_strict_mode disabled and/or sql_mode set to just NO_ENGINE_SUBSTITUTION doesn't make a difference.

[m-vo]

Had a quick look in the debugger. It's the same issue as in here: contao/core-bundle#918 (comment)

So _default equals "''" in $fromSchema vs. "" in $toSchema.

(Also: doctrine entities get created successfully but then are missing in the $fromSchema. Not sure if this had worked before.)

[leofeyer]

See contao/core-bundle#918 (comment)

[fritzmg]

@leofeyer all tickets (including https://jira.mariadb.org/browse/MDEV-13132) are closed now, yet the issue still exists.

[m-vo]

I am still not sure if it's a MariaDB or a doctrine issue. But it looks like it is the latter as doctrine seems to only support MariaDB 10.2. as of v2.7 which is not released yet.

I can confirm that using the current doctrine/dbal dev-master branch solves the default value problem but it could still take a long time until a stable branch will get released. So unfortunately Contao is not compatible to Maria DB 10.2 right now, right? :-/

[leofeyer]

Correct, you need Doctrine 2.7 (not yet released).