Hello,

I was using panels on the 8.x-3.x-dev branch but due to recent changes (one or two weeks I think) I can't add Panels Variant anymore.
I am using the Page Manager and the Layout Plugin modules with Panels.

Steps to reproduce:
1 - Enable page manager, layout plugin and panels modules (on dev branch for panels)
2 - Create a new page with page manager module
3 - Try to add a new variant and choose panels

You should have the builder select but not anymore the layout select in the popin. And when you continue clicking on "Save", an exception is thrown by Drupal:

Drupal\Component\Plugin\Exception\PluginNotFoundException: The "" plugin does not exist. in Drupal\Core\Plugin\DefaultPluginManager->doGetDefinition() (line 52 of core/lib/Drupal/Component/Plugin/Discovery/DiscoveryTrait.php).

I have reverted the panels module on 8.x-3.0-beta4 version and the bug doesn't exist. I don't really know why it happens...

Thank you for reading this and I hope it is not too hard to fix.

Comments

phjou created an issue. See original summary.

phjou’s picture

phjou
he/him
Location Vancouver 🇨🇦 🇪🇺
commented

I have tried to update the modules one by one but apparently we need to update all of them. Updating the three modules: layout_plugin, page_manager and panels with the dev branches fix the problem or at least you can resolve it without a crash page.

After updating the modules and clear caches. The interface has changed a lot but it is pretty cool. You have now tabs to configure your page. You can choose again your panel in the "Layout" tab and the "Content" tab will appear correctly again instead of displaying an error.

I hope it will help some people.

I have fixed the modules states to avoid updating their code automatically on the production environment. So there is my drush make file if some of you are interested.

projects[layout_plugin][type] = module
projects[layout_plugin][subdir] = contrib
projects[layout_plugin][download][type] = "git"
projects[layout_plugin][download][url] = "git://git.drupal.org/project/layout_plugin.git"
projects[layout_plugin][download][revision] = "822e51a9d1a798ebc4ec30dced6da2484f580400"
projects[layout_plugin][download][branch] = "8.x-1.x"

projects[page_manager][type] = module
projects[page_manager][download][type] = git
projects[page_manager][subdir] = contrib
projects[page_manager][download][url] = "git://git.drupal.org/project/page_manager.git"
projects[page_manager][download][revision] = "ca4ee1a72f812625f8ed767f50c43c81146e1769"
projects[page_manager][download][branch] = "8.x-1.x"

projects[panels][type] = module
projects[panels][download][type] = git
projects[panels][subdir] = contrib
projects[panels][download][url] = "git://git.drupal.org/project/panels.git"
projects[panels][download][revision] = "f1156f534f394c6daea7c6838ef95aab0cc6ad3d"
projects[panels][download][branch] = "8.x-3.x"

Have a nice day.

phjou’s picture

phjou
he/him
Location Vancouver 🇨🇦 🇪🇺
commented
Status: Active » Closed (outdated)
ransomweaver’s picture

ransomweaver commented
Priority: Normal » Major
Status: Closed (outdated) » Active

I confirm this problem is present in beta-5/dev but not beta-4. You can no longer create any panels variation (doesn't show the layout selector), but it doesn't break any existing layouts.

The problem is resolved if you use the dev version of page_manager (after alpha-24). I am making this an open bug because of the severity of the problem if encountered, and because it seems problematic to have a beta that opaquely depends on another module's dev branch.

millionleaves’s picture

millionleaves commented

I'm experiencing something similar to this. Unsure if it's the same issue, or something else since I am able to choose a layout but get this error in the server logs when trying to proceed.

I've just installed the release version of Panels, 8.x-4.0. This requires the experimental core module Layout Discovery rather than the contrib Layout Plugin.

With Page Manager I am able to create a new variant and get the option to select the type of variant (e.g. Panels).

I am then asked for the Builder (Standard is the only option) after which I am asked to choose a layout. Various layouts are available. Whichever layout I choose, I get the error described above.

venge’s picture

venge commented

I have the same problem as #5 since I updated panels beta1 to 8.X-4.0 and page_manager 4.0.0-beta1 to beta2. Layout selection when creating a new page give the same error.

majdi’s picture

majdi commented

I confirm the error #2 on selecting layout

arijits.drush’s picture

arijits.drush
Primary language English
Location India
commented

This bug again coming up after updating to panel 8.x-4.0

karolus’s picture

karolus commented
Version: 8.x-3.x-dev » 8.x-4.x-dev

Quick addition to this--with Drupal core 8.3.x onward, the Layout Plugin module is no longer needed, since Layout Discovery is now in core (but experimental).

Nonetheless, I'm still getting this error message:
Drupal\Component\Plugin\Exception\PluginNotFoundException: The "onecol" plugin does not exist. in Drupal\Core\Plugin\DefaultPluginManager->doGetDefinition() (line 52 of /Users/karolus/Sites/drupal8panels/core/lib/Drupal/Component/Plugin/Discovery/DiscoveryTrait.php).

I'm rooting through the code to try to find a solution.

japerry’s picture

japerry
Location KOMK
commented
Status: Active » Closed (duplicate)

This is a duplicate of #2874489: Drupal\Component\Plugin\Exception\PluginNotFoundException: The "" plugin does not exist. and partially a duplicate of the layout_discovery change. While we've made an update path for core, you must manually change any theme layouts you may have on your site.

millionleaves’s picture

millionleaves commented

Thanks. I installed Panels 4.1 and this issue no longer occurs.