Fatal error when setting the body of a mailable with null

[jonasraoni]

Describe the bug
When trying to create a submission in OMP, I've got the Exception below, due to the absence of a body at the email template SUBMISSION_NEEDS_EDITOR.
Perhaps the template body shouldn't be null, but the Mailable class should deal with it.

Slim Application Error:
Type: TypeError
Message: PKP\mail\Mailable::body(): Argument #1 ($view) must be of type string, null given, called in /var/www/html/lib/pkp/classes/observers/listeners/AssignEditors.php on line 115
File: /var/www/html/lib/pkp/classes/mail/Mailable.php
Line: 257
Trace: #0 /var/www/html/lib/pkp/classes/observers/listeners/AssignEditors.php(115): PKP\mail\Mailable->body(NULL)
#1 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(441): PKP\observers\listeners\AssignEditors->handle(Object(PKP\observers\events\SubmissionSubmitted))
#2 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(249): Illuminate\Events\Dispatcher->Illuminate\Events\{closure}('PKP\\observers\\e...', Array)
#3 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php(451): Illuminate\Events\Dispatcher->dispatch('PKP\\observers\\e...')
#4 /var/www/html/lib/pkp/classes/submission/Repository.php(595): event(Object(PKP\observers\events\SubmissionSubmitted))
#5 /var/www/html/lib/pkp/api/v1/submissions/PKPSubmissionHandler.php(717): PKP\submission\Repository->submit(Object(APP\submission\Submission), Object(APP\press\Press))
#6 [internal function]: PKP\API\v1\submissions\PKPSubmissionHandler->submit(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Array)
#7 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/Handlers/Strategies/RequestResponse.php(40): call_user_func(Array, Object(Slim\Http\Request), Object(PKP\core\APIResponse), Array)
#8 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/Route.php(281): Slim\Handlers\Strategies\RequestResponse->__invoke(Array, Object(Slim\Http\Request), Object(PKP\core\APIResponse), Array)
#9 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(117): Slim\Route->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#10 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/Route.php(268): Slim\Route->callMiddlewareStack(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#11 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/App.php(503): Slim\Route->run(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#12 /var/www/html/lib/pkp/classes/security/authorization/internal/ApiAuthorizationMiddleware.php(90): Slim\App->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#13 [internal function]: PKP\security\authorization\internal\ApiAuthorizationMiddleware->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Slim\App))
#14 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(PKP\security\authorization\internal\ApiAuthorizationMiddleware), Array)
#15 [internal function]: Slim\DeferredCallable->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Slim\App))
#16 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\DeferredCallable), Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Slim\App))
#17 /var/www/html/lib/pkp/classes/security/authorization/internal/ApiCsrfMiddleware.php(56): Slim\App->Slim\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#18 [internal function]: PKP\security\authorization\internal\ApiCsrfMiddleware->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#19 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(PKP\security\authorization\internal\ApiCsrfMiddleware), Array)
#20 [internal function]: Slim\DeferredCallable->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#21 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\DeferredCallable), Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#22 /var/www/html/lib/pkp/classes/security/authorization/internal/ApiTokenDecodingMiddleware.php(140): Slim\App->Slim\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#23 [internal function]: PKP\security\authorization\internal\ApiTokenDecodingMiddleware->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#24 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(PKP\security\authorization\internal\ApiTokenDecodingMiddleware), Array)
#25 [internal function]: Slim\DeferredCallable->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#26 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\DeferredCallable), Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#27 /var/www/html/lib/pkp/classes/handler/APIHandler.php(83): Slim\App->Slim\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#28 [internal function]: PKP\handler\APIHandler->PKP\handler\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#29 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array)
#30 [internal function]: Slim\DeferredCallable->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#31 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\DeferredCallable), Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#32 /var/www/html/lib/pkp/classes/handler/APIHandler.php(100): Slim\App->Slim\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#33 [internal function]: PKP\handler\APIHandler->PKP\handler\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#34 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array)
#35 [internal function]: Slim\DeferredCallable->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#36 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\DeferredCallable), Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#37 /var/www/html/lib/pkp/classes/handler/APIHandler.php(105): Slim\App->Slim\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#38 [internal function]: PKP\handler\APIHandler->PKP\handler\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#39 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array)
#40 [internal function]: Slim\DeferredCallable->__invoke(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#41 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(70): call_user_func(Object(Slim\DeferredCallable), Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#42 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(117): Slim\App->Slim\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#43 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/App.php(392): Slim\App->callMiddlewareStack(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#44 /var/www/html/lib/pkp/classes/handler/APIHandler.php(98): Slim\App->process(Object(Slim\Http\Request), Object(PKP\core\APIResponse))
#45 [internal function]: PKP\handler\APIHandler->PKP\handler\{closure}(Object(Slim\Http\Request), Object(PKP\core\APIResponse), Object(Closure))
#46 /var/www/html/lib/pkp/lib/vendor/slim/slim/Slim/DeferredCallable.php(57): call_user_func_array(Object(Closure), Array)
#47 [internal function]: Slim\DeferredCallable->__invoke(Object(Slim\Http

What application are you using?
OMP 3.4

[jonasraoni]

@asmecher / @Vitaliy-1 I was going to merge right away, but as I've created PRs, here they are:

• pkp/pkp-lib#9444 Allowed passing null to the Mailable::body() method #9445
• pkp/pkp-lib#9444 Allowed passing null to the Mailable::body() method #9446

I've got this exception in our test drive, AFAICR it was missing some template data for the en locale.
I didn't see how the email migration is working, but perhaps there's something missing to create/recreate non-existent templates.

[jonasraoni]

I've merged the PRs as there's nothing special on them.

I just wanted to:

• Discuss the non-existent template data: @Vitaliy-1 said that will take a look at the https://omp34.testdrive.publicknowledgeproject.org
• Send a heads up about typed arguments: I think it's better for us to use ?type, unless a value is really required 🤔

[Vitaliy-1]

Thanks, @jonasraoni!

This issue is related: #9202, I'm planning to migrate all of the missing template for 3.5 release

I'd add a warning if mailable is sent with an empty body, just for such cases - to know if the template is missing.