Warning: Invalid argument supplied for foreach() in /ds/ds.module on line 504

I'm assuming this is happening when you use "class: '\Drupal\ds\Plugin\DsLayout'" in your layout definition, so why don't we merge the DsLayout default configuration to $variables['settings'] before is processed on ds_preprocess_ds_layout() or - even better - ds_theme_registry_alter()?

Worth noticing re-saving the affected view mode settings fixes the issue.

Re-saving the view mode settings didn't fix this for me.

The patch in #2 gets rid of the Warning but produces a Notice in its place:

Undefined index: wrappers in ds_preprocess_ds_layout() (line 504

Line 504 should be:
if (isset($layout_settings['wrappers']) && !empty($layout_settings['wrappers'])) {
instead of:
if (!is_null($layout_settings['wrappers'])) {

Revised patch attached.

@DigitalFrontiersMedia can you provide the interdiff ?

Thanks!

interdiff attached. However, it gave an odd message upon completion:

stephen@MotherPhoenix-3:~/Downloads [10:52:05]: interdiff invalid_argument_in_ds_module-2904575-2.patch invalid_argument_in_ds_module-2904575-7.patch > interdiff_7-9.txt
patch unexpectedly ends in middle of line

+++ b/ds.module
@@ -501,6 +501,6 @@
+  if (isset($layout_settings['wrappers']) && !empty($layout_settings['wrappers'])) {

!empty() produces in this case the same effect as isset() and still doesn't ensure $layout_settings['wrappers'] is an array.

I think what you want is isset($layout_settings['wrappers']) && is_array($layout_settings['wrappers']) (or !empty($layout_settings['wrappers']) && is_array($layout_settings['wrappers'])).

!empty() produces in this case the same effect as isset() and still doesn't ensure $layout_settings['wrappers'] is an array.

No, use of !empty in addition to isset is for different reasons. isset makes sure the array key 'wrappers' is actually valid and its value is not NULL, !empty makes sure its value isn't just ''.

Additional assurance that it is an array (and not null and not an empty array) is a good safety check.

Thanks @DigitalFrontiersMedia, the preprocess warning is no longer bugging my users! (Not marking RTBC since I have not reviewed the code.)

No, use of !empty in addition to isset is for different reasons. isset makes sure the array key 'wrappers' is actually valid and its value is not NULL, !empty makes sure its value isn't just ''.

From empty() PHP documentation: " No warning is generated if the variable does not exist. That means empty() is essentially the concise equivalent to !isset($var) || $var == false. ".

So "!empty() produces in this case the same effect as isset() and still doesn't ensure $layout_settings['wrappers'] is an array." is still valid. One between isset() and !empty() can be removed, and the only remaining task is still to make sure is_array($layout_settings['wrappers']).

I see what you're saying now.

That being the case, and since checking if it's an array before passing into the loop is recommended, we should probably use
!empty($layout_settings['wrappers']) && is_array($layout_settings['wrappers'])
since there's no point bothering to enter that loop if it's set and an array but that array is empty.

@akalata Glad to hear! I know how hard it can be when you've got lots of users coming to you with complaints.

Per discussion with gambry, it looks like while the patch stops the warnings and such, it may not yet be the ideal, final solution. Hopefully, we'll get that done and hopefully have it committed soon.

Totally agree @DigitalFrontiersMedia !

Thanks

New patch with suggestion per gambry.

Patch in #17 looks good and works well.

Patch in 17 also fixed my issues! Thanks!

Does anyone have steps to reproduce to trigger this notice ? I'm trying to think if the actual problem isn't somewhere else.

Also, maybe something like this:

  $layout_settings += ['wrappers' => []];

is a more elegant line than moving the complete code into one if check.

Also, maybe something like this:

$layout_settings += ['wrappers' => []];
is a more elegant line than moving the complete code into one if check.

Pffft. Yeah, sure that works too...if you want to get all fancy and elegant. :-D

If you're looking for initial cause, I think Gambry is probably on the right track in #5.

Can't say I really know how to consistently reproduce, unfortunately.

Can't say I really know how to consistently reproduce, unfortunately.

Mmm, no problem. I committed it like my suggestion, should be good. You're all still credited though, don't worry :)

Amazing solution though! Thanks @swentel