Migration from D7 to D9

1. +++ b/migrations/mail_system_settings.yml
   @@ -0,0 +1,29 @@
   +  defaults/sender:
   
   +++ b/src/Plugin/migrate/process/MailSystemModules.php
   @@ -0,0 +1,42 @@
   +    unset($value['default-system']);
   

   Let's add a comment somewhat like this:

       // The "default-system" key-value pair is not for a module-specific
       // migration, but for the default. This is already handled elsewhere in the
       // migration process pipeline ("defaults/sender" and "defaults/formatter").
   

   … that will help future readers understand why this is happening.

2. +++ b/migrations/mail_system_settings.yml
   @@ -0,0 +1,29 @@
   +migration_dependencies:
   +  required:
   +    - drupal:filter
   

   This dependency does not seems to make sense? It looks like a module dependency in a module's *.info.yml file (see for example core/modules/editor/editor.info.yml), but that's not the same as a migration plugin's YAML file.

   I think these 3 lines can just be deleted entirely :)

3. +++ b/src/Plugin/migrate/process/MailSystemModules.php
   @@ -0,0 +1,42 @@
   +      $value['module'] = explode("_", $key);
   ...
   +        $value[$value['module'][0]][$value['module'][1]]['formatter'] = $data;
   

   $value['module'] makes it sound like the assigned value will be a module name (i.e. a string). But it won't be. It's always an array.

   So let's change this to

   [$module, $index] = explode("_", $key);
   

   Then you can simplify

   $value[$value['module'][0]][$value['module'][1]]['formatter'] = $data;
   

   to

   $value[$module][$index]['formatter'] = $data;
   

   Easier to read, right? 😊 Bonus: you can delete the

   unset($value['module']);
   

   at the end as well!

Perfect! 👍

> Perfect! 👍

I'll just believe you on that ;)

Personally, I'm not sure how useful this migration is. these things weren't plugins in D7, there's no guarantee that the plugin ID's are still the same and that you even still want to use the same modules in D8+. Seems like something that you should probably manually reconfigure, but I suppose it doesn't hurt.

It seems that this patch just adds a new directories structure (/b/..) with copies of the current (8.x-4.4) version files :
- mail_system_settings.yml
- MailSystemModules.php

I'm still getting a migration error which may not be related to mail_system :

[error]  Error: Cannot use string offset as an array in Drupal\mailsystem\Plugin\migrate\process\MailSystemModules->transform() (line 36 of /var/www/html/web/modules/contrib/mailsystem/src/Plugin/migrate/process/MailSystemModules.php) 
.. 
[04-Oct-2022 14:39:41 Europe/Berlin] Error: Cannot use string offset as an array in /var/www/html/web/modules/contrib/mailsystem/src/Plugin/migrate/process/MailSystemModules.php

So this patch can be applied but it just adds useless files as far as I know.

I'm also getting that same error.

I'm not sure that adding broken functionality is a great UX?

Inserting some debugging I see that in the transform function in
web/modules/contrib/mailsystem/src/Plugin/migrate/process/MailSystemModules.php

the code expects $value to be a 3xn array i.e. $value[a][b][c] however the error occurs due to it receiving

array (
  'mimemail' => 'MimeMailSystem',
  'update_status_notify' => 'MimeMailSystem',
)

interesting the "index" is NULL in this case?

There is still error with this module during the Migration.

Error: Cannot use string offset as an array in Drupal\mailsystem\Plugin\migrate\process\MailSystemModules->transform() (line 36 of /web/modules/contrib/mailsystem/src/Plugin/migrate/process/MailSystemModules.php).

The code line at Line # 36 of MailSystemModules.php file -
$value[$module][$index]['formatter'] = $data;

Since this issue is closed(fixed) and only maintainers can reopen, so would like this to be attended by the maintainers please and @srishtiiee at Acquia to please fix this broken functionality.

Thanks

I have applied the patch and this issue is not yet resolved.

Created a follow-up issue for the reports after the initial commit #3463222: Error: Cannot use string offset as an array in MailSystemModules.php on line 36