Configuration translation save triggers an undefined index notice

The bug exists in all 8.x branches.

I added a comment to the patch.

#2 tested and works well: notice is not exist!

Looks like we're missing test coverage then.

In fact this patch applies to 8.2, and does not applies to 8.1.
In my opinion this ticket should target 8.2 first, and then be moved to 8.1. I am wrong ?
I guess we need @alexpott 's opinion.

To me, this seems to fit the definition of a Major bug.

This is a minor bug, because PHP notices do not break anything, and as far as I can see nothing's buggy apart from the notice.

I think this is almost ready to be RTBC'd. However, the newly introduced test method must also confirm the existence of the new translation.

At some point in configuring my Drupal 8 site I experienced the same Notice, but the field wasn't translatable anymore to other languages.
I can confirm the patch in #18 (configuration-2746253-14--d8.1.patch) resolved this issue (using Drupal 8.1.8)

RTBC.

PS: I do consider this a major issue. Not because of the notice but because it prevented saving and thus translating a label. In my case I had a non-translatable field (value) with a label that needed translating.

Exceptions are thrown.

+++ b/core/modules/config_translation/src/Form/ConfigTranslationFormBase.php
@@ -193,6 +193,12 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     foreach ($this->mapper->getConfigNames() as $name) {
+
+      // Skip the config if it does not have translatable data.
+      if (!isset($form_values[$name])) {
+        continue;
+      }
+

Maybe we can do this better by doing:
foreach ($form_values as $name => $value) {
And then doing
$element->setConfig($base_config, $config_translation, $value);

It's great to see a test. I've confirmed it fails without the fix.

Will this be fixed in the next Drupal version? Do I need the patch or can I wait?
Thanks

Fix worked for me.

Fixed per comments in #24

Tested, worked

#28 fix the issue and I can now translate fields label.

Committed and pushed 240524f to 8.4.x and fb8b2ce to 8.3.x. Thanks!

Thanks to everyone for all the comments confirming the fix works. I credited myself because my comment in #24 directly changed the patch.