Schema Magnolia Derivation inlines a null that breaks Scala 3's -Yexplicit-nulls compiler option

[coryfklein]

Tapir version: 1.10.15

Scala version: 3.4.2

The generated example Tapir project won't compile with Scala 3's -Yexplicit-nulls compiler option due to how SchemaMagnoliaDerivation#derived inlines an unsafe call to java.lang.ThreadLocal#get

What is the problem?

Generate a project with these settings:

Then turn on the -Yexplicit-nulls flag.

You can see the issue manifesting in booksListing in my IntelliJ setup like so:

Error at the end of line 40

Found:    scala.collection.mutable.Set[String] | Null
Required: scala.collection.mutable.Set[String]

Explanation
===========

Tree:       9|SchemaMagnoliaDerivation_this.
    119|  sttp$tapir$generic$auto$SchemaMagnoliaDerivation$$inline$deriveCache.
    119|  get()
I tried to show that
  scala.collection.mutable.Set[String] | Null
conforms to
  scala.collection.mutable.Set[String]
but none of the attempts shown below succeeded:

  ==> scala.collection.mutable.Set[String] | Null  <:  scala.collection.mutable.Set[String]
    ==> Null  <:  scala.collection.mutable.Set[String]  = false

The tests were made under a constraint with:
 uninstantiated variables: T, A, T, A
 constrained types: [T](value: T): sttp.tapir.generic.Derived[T],
  [A](elems: A*): scala.collection.mutable.Set[A],
  [T]
    (schemaType: sttp.tapir.SchemaType[T],
      name: Option[sttp.tapir.Schema.SName], isOptional: Boolean,
      description: Option[String], default: Option[(T, Option[Any])],
      format: Option[String], encodedExample: Option[Any],
      deprecated: Boolean, hidden: Boolean,
      validator: sttp.tapir.Validator[T], attributes:
      sttp.tapir.AttributeMap): sttp.tapir.Schema[T]
  ,
[A](using x$1: scala.deriving.Mirror.Of[A]): sttp.tapir.Schema[A]
 bounds:
     T
     A
     T
     A
 ordering:
 co-deps:
 contra-deps:
 [30:36]

[adamw]

Do you think that #3970 will satisfy the compiler? I'm not familiar with explicit-nullss