Date field empty after migration d7 d8

The date stored there in D8 is actually wrong - the format is 2016-10-25T16:43:21. Looks like we need a process plugin to translate.

See also #2566779: Migration D6 > D8 of CCK date fields.

If you need a quick fix for this problem until the bug is really fixed the code below will get things semi-working. It's not the right way to do this but it will convert the date to the correct format for drupal 8. My table name was node__field_eventstart and the column is field_eventstart_value. Change those in the code below to match your table and field. Backup your database first... then save this file as fix_date.php and run with the command line php fix_date.php.

$link = mysqli_connect("127.0.0.1", "user", "pass", "db_name");

if (!$link) {
    echo "Error: Unable to connect to MySQL." . PHP_EOL;
    echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
    echo "Debugging error: " . mysqli_connect_error() . PHP_EOL;
    exit;
}

$res = mysqli_query($link, "select entity_id, field_eventstart_value from node__field_eventstart");
while ($row = $res->fetch_assoc()) {
    echo $row['entity_id'] . " " . $row['field_eventstart_value']. "\n";
    $res2 = mysqli_query($link, "UPDATE node__field_eventstart dest, (select field_eventstart_value from node__field_eventstart where entity_id = ".$row['entity_id']." ) src SET dest.field_eventstart_value = DATE_FORMAT( src.field_eventstart_value, '%Y-%m-%dT%H:%i:%S') WHERE entity_id =".$row['entity_id']."");
}

mysqli_close($link);

@mikeryan
Our team built process plugin to convert date (attache here, custom_migrate.zip). What is best way to package it so it can be tested and included in core?

This work is already in progress at #2820490: FormatDate process plugin and #2566779: Migration D6 > D8 of CCK date fields.

Thanks for pointing me to the new thread! I will do testing and report results. Can I ask here - is there thread for converting longtext-plaintext format for drupal7 to text-plain,long in drupal8?
thanks!

@irinaz: I was a bit short in my previous reply, just threw that out there on my way out the door. For information on contributing to Drupal, the main resource is https://www.drupal.org/docs/develop. More specifically, for contributing patches to Drupal, see https://www.drupal.org/node/707484.

In terms of finding an existing issue, the issue queue is searchable - for example, https://www.drupal.org/project/issues/search/drupal?text=format&project_... searches for open migration system issues mentioning "format". In that list, #2842222: D7 Plain text fields incorrectly migrated to D8 as Text (formatted) may be what you're looking for.

@mikeryan - thank you VERY much, it is the issue. Our team with try to contribute what we can to have both issues moved forward.

$link = mysqli_connect("127.0.0.1", "user", "pass", "db_name");

if (!$link) {
    echo "Error: Unable to connect to MySQL." . PHP_EOL;
    echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
    echo "Debugging error: " . mysqli_connect_error() . PHP_E&lt;code&gt;</code>OL;
    exit;
}

$res = mysqli_query($link, "select entity_id, field_date_value from table");
while ($row = $res->fetch_assoc()) {
    echo $row['entity_id'] . " " . $row['field_date_value ']. "\n";
    $res2 = mysqli_query($link, "UPDATE table dest SET dest.field_date_value = DATE(STR_TO_DATE(field_date_value , '%Y-%m-%dT%H:%i:%S')) WHERE entity_id =".$row['entity_id']."");
}

mysqli_close($link);

@vpa24 I restored the original issue summary. The meaning of the edit you made is not clear.

Sorry guys, but I don't understand why this was closed as duplicate refering to a d6 > d8 issue.
Reopening this cause I'm facing the issue on d7 > d8 hoping it helps someone.

I've two field date on two different content types. One of them is working, the other one is not... I figured out that the one is working was set (in the configuration file in the sync folder) on datetime_type: datetime and the other one was datetime_type: date.

I used the code suggested above to change the format to date only and it worked!

basically I've changed this part:
DATE_FORMAT( src.field_eventstart_value, '%Y-%m-%dT%H:%i:%S')
to this:
DATE_FORMAT( src.field_eventstart_value, '%Y-%m-%d')

This is my custom module can help fix date. You just go to admin/config/development/fix-date
https://github.com/vpa24/fix_date/

This is my custom module can help fix date. You just go to admin/config/development/fix-date
https://github.com/vpa24/fix_date/

Here is a patch without a test. Once applied, recreate migrations and you should get the right to_format for fields that have a granularity of just the date.

Oops. I marked it as not to be tested. Uploading again.

Here is an updated patch that should fix the multiple test warnings.

Here I have extended test coverage. This is the coverage report for the class that I modified before this patch:

And here is using this patch:

This patch adds an adjustment to core/modules/datetime/tests/src/Unit/Plugin/migrate/field/DateFieldLegacyTest.php so tests pass.

ON a very brief look, the change here looks similar to what is done in #3007102: Migrating to Date-only field does not drop time value. What is the difference?

Yeah, it seems the same bug @quietone, just that I am testing the class differently.

Feel free to mark this one as a duplicate if you consider it fit.

@juampynr, thanks that helped. I don't see similar tests in the other issue so let move the tests here over to #3007102: Migrating to Date-only field does not drop time value. Once that is done this can be marked as a duplicate.

I've merged the explicit unit tests from here into #3007102: Migrating to Date-only field does not drop time value and am closing this as a duplicate.
@juampynr is already credited on that issue, and I've transferred @vpa24's credit over there as well.