Magento 2.1.0: db fields with mysql default value CURRENT_TIMESTAMP cannot be updated through the EntityManager

[heldchen]

Steps to reproduce

1. Install Magento from develop branch.
2. load a CMS Page through $model = $pageRepository->getById(1);
3. modify the last update timestamp: $model->setUpdateTime('2016-09-01 00:00:00');
4. save through $pageRepository->save($model);

Expected result

1. the cms_pagedatabase column update_time of entity 1 contains 2016-09-01 00:00:00

Actual result

1. the database column "update_time" contains the old value

the reason being in Magento\Framework\EntityManager\Db\UpdateRow:prepareData:

        foreach ($connection->describeTable($metadata->getEntityTable()) as $column) {
            if ($column['DEFAULT'] == 'CURRENT_TIMESTAMP' || $column['IDENTITY']) {
                continue;
            }

as the column update_time has the default value CURRENT_TIMESTAMP, the field is not appended to the $output array.

please note: i'm aware that cms_page.update_time is auto-updated through mysql's "on update" attribute, I'm merely using this existing model as an example that can be easily reproduced without having to write tons of code.

[SerhiyShkolyarenko]

@heldchen thank you for reporting!
We created internal issue MAGETWO-58479.

[veloraven]

This issue was already fixed for develop.
Internal ticket for ver. 2.1 - MAGETWO-58514