Notice: Undefined index: #default_value in Drupal\Core\Datetime\Element\Datetime::valueCallback() (line 103

Please update the issue summary with the steps needed to reproduce the bug. We must understand the conditions that cause the notice. Please use the issue template.

Adding the Patch for the fix.

Thank you for posting this patch, however you are using the wrong status. We still need the issue summary updated it to understand what situation causes this error.

Hi,

I have contacted Shah, who created bug and updated info and tested with the patch and it is working fine. please review and mark it as fixed.

Thanks
Elan

This issue is over 2 years old. Will it be committed to core?
I've re-rolled the patch for 8.4.

I tested the patch in #14 on a clean install of Drupal 8.6 and it works. No more warning showing up in the logs after applying the patch.

The patch looks good, we just need to fix one thing before it can be committed:

+++ b/core/lib/Drupal/Core/Datetime/Element/Datetime.php
@@ -96,7 +96,7 @@ public static function valueCallback(&$element, $input, FormStateInterface $form
+      $date = isset($element['#default_value']) ? $element['#default_value'] : null;

According to our coding standards, null needs to be upper case.

Perfect :)

Sorry, if this is a bug and we're fixing a regression, we need a test

I agree with @larowlan we need a test.

Attaching patch with test.

Fixed typo.

+++ b/core/modules/datetime/src/Tests/Form/DateDefaultValueTest.php
@@ -0,0 +1,32 @@
+class DateDefaultValueTest extends WebTestBase {

The test case should be added to the existing \Drupal\KernelTests\Core\Datetime\DatetimeElementFormTest test class.

Please review and let me know if any changes required.

Looks great!

I think we should add a comment describing what we are testing in this form element. In the future, we will not know for what purpose this element has been added.

Agreed, that comment is very useful.

Crediting @larowlan and @amateescu for patch review. Crediting @shahgm for creating the issue.

Committed ea33b15 and pushed to 8.7.x. Thanks!

Doesn't apply to 8.6.x so have only fixed 8.7.x. If someone wants to backport then this would be eligible.

Found this via #2419131-93: [PP-1] #states attribute does not work on #type datetime

Backporting this would be trivial if #2992580: Custom callbacks doesn't work was also in 8.6.x, since that's where the test class this patch is extending was first added.

With 2992580-09.patch applied to 8.6.x, this patch applies (with minor fuzz).

Can we get #2992580 in and then I'll upload a backport here? I queued a re-test of that against 8.6.x, and I'll RTBC once the bot is happy.

Thanks!
-Derek

Yay, @alexpott just committed #2992580: Custom callbacks doesn't work to 8.6.x, and now #32 applies cleanly, and core/tests/Drupal/KernelTests/Core/Datetime/DatetimeElementFormTest.php passes locally.

RTBC.

Thanks!
-Derek

Bot is confused. #32 is all green for 8.6.x.

According to @drumm in Slack, the bot will continue to be confused until a new file is uploaded in this case. :/ So here's #32 again, so we don't keep getting this marked 'needs work' each day it isn't backported.

Cherry-picked the 8.7.x back to 8.6.x

Thanks!