Add a fallback type check to Utility::isTextType()

Thanks for your work!

There are some issues with your patch, though:

1. +++ b/src/Utility.php
   @@ -68,9 +68,11 @@ public static function isTextType($type, array $text_types = array('text')) {
   +    $default = in_array($type, $text_types);
   +    $fallback = in_array($type->getFallbackType(), $text_types);
   +    return ($default || $fallback) ? TRUE : FALSE;
   

   I would return early in case the first check works out. Also, you should only check the fallback type if !$type->isDefault().
   Mostly, though, $type is a string at this point. You'll first need to load the appropriate data type plugin for this to work.

2. +++ b/src/Utility.php
   @@ -68,9 +68,11 @@ public static function isTextType($type, array $text_types = array('text')) {
   +    return ($default || $fallback) ? TRUE : FALSE;
   

   The condition already produces a boolean, the trinary operator serves no purpose there.

3. +++ b/src/Utility.php
   @@ -68,9 +68,11 @@ public static function isTextType($type, array $text_types = array('text')) {
   -
   +
   

   What is this change?
   Might be the reason the patch fails to apply.

Also, if we fix this, we can remove the @todo comment in that method. (Speaking of which – that comment moved yesterday, so maybe that's the reason the patch won't apply. Please use the very latest dev version!)

Yes, this looks a lot better, thanks a lot!
Except that you can just use $manager->createInstance() instead of iterating over all instances (which we might want to override to add caching, come to think of it) this already looks like the correct solution. We'll just have to fix the test cases to add a mockup of the plugin manager in a container. (See, e.g., our EntitySerializationTest for an example of adding mockup services.)

Thanks, great work!
I just reformatted according to my preferences, but your version was completely correct. Thanks again!
The attached patch also contains the discussed caching and should fix the reported test fails. (I get some more fails now, but want to make sure the test bot sees them, too, before working on them.)

I'm not very good at this.

Committed.
Thanks again for your work on this, everyone!