add comments

Author: arnaud-daroussin

modules/scala-api/src/main/scala-3/org/apache/flinkx/api/TypeTagMacro.scala

@@ -12,6 +12,7 @@ object TypeTagMacro:
     val flagsA         = symA.flags
     val isModuleExpr   = Expr(flagsA.is(Flags.Module))
     val isCachableExpr = Expr(A match {
+      // this type is not cachable if one of its type args is abstract
       case a: AppliedType => !a.args.exists { t => t.typeSymbol.isAbstractType }
       case _              => true
     })

modules/scala-api/src/test/scala-2/org/apache/flinkx/api/GenericCaseClassScala2Test.scala

@@ -36,14 +36,15 @@ class GenericCaseClassScala2Test extends AnyFlatSpec with should.Matchers {
 
     if (classOf[Cat].isAssignableFrom(aClass)) {
       aInfo should be theSameInstanceAs catInfo
-      aBasketInfo should be theSameInstanceAs catBasketInfo
+      aBasketInfo should be theSameInstanceAs catBasketInfo // Type info of Basket[A] finds the cached type info of Basket[Cat]
     }
     if (classOf[Dog].isAssignableFrom(aClass)) {
       aInfo should be theSameInstanceAs dogInfo
-      aBasketInfo should be theSameInstanceAs dogBasketInfo
+      aBasketInfo should be theSameInstanceAs dogBasketInfo // Type info of Basket[A] finds the cached type info of Basket[Dog]
     }
     catBasketInfo.asInstanceOf[ProductTypeInformation[A]].getFieldTypes()(0) should be theSameInstanceAs catInfo
     dogBasketInfo.asInstanceOf[ProductTypeInformation[A]].getFieldTypes()(0) should be theSameInstanceAs dogInfo
+    // Type info of Basket[A] holds a type info of the good type (Cat or Dog) found in the cache
     aBasketInfo.asInstanceOf[ProductTypeInformation[A]].getFieldTypes()(0) should be theSameInstanceAs aInfo
   }
 

modules/scala-api/src/test/scala-3/org/apache/flinkx/api/GenericCaseClassScala3Test.scala

@@ -28,19 +28,20 @@ class GenericCaseClassScala3Test extends AnyFlatSpec with should.Matchers {
     val catBasketInfo: TypeInformation[Basket[Cat]] = implicitly[TypeInformation[Basket[Cat]]]
     // cacheKey=org.apache.flinkx.api.GenericCaseClassTest.Basket[org.apache.flinkx.api.GenericCaseClassTest.Dog] => OK
     val dogBasketInfo: TypeInformation[Basket[Dog]] = implicitly[TypeInformation[Basket[Dog]]]
-    // cacheKey=org.apache.flinkx.api.GenericCaseClassTest.Basket[A] => not cached
+    // cacheKey=org.apache.flinkx.api.GenericCaseClassTest.Basket[A] => Basket[A] is not cachable
     val aBasketInfo: TypeInformation[Basket[A]]     = implicitly[TypeInformation[Basket[A]]]
 
     if (classOf[Cat].isAssignableFrom(aClass)) {
       aInfo should be theSameInstanceAs catInfo
-      // aBasketInfo should be theSameInstanceAs catBasketInfo // Fails => aBasketInfo is not cached
+      aBasketInfo shouldNot be theSameInstanceAs catBasketInfo // Basket[A] is not cachable
     }
     if (classOf[Dog].isAssignableFrom(aClass)) {
       aInfo should be theSameInstanceAs dogInfo
-      // aBasketInfo should be theSameInstanceAs dogBasketInfo // Fails => aBasketInfo is not cached
+      aBasketInfo shouldNot be theSameInstanceAs dogBasketInfo // Basket[A] is not cachable
     }
     catBasketInfo.asInstanceOf[ProductTypeInformation[A]].getFieldTypes()(0) should be theSameInstanceAs catInfo
     dogBasketInfo.asInstanceOf[ProductTypeInformation[A]].getFieldTypes()(0) should be theSameInstanceAs dogInfo
+    // Type info of Basket[A] is not cached, but it holds a type info of the good type (Cat or Dog) found in the cache
     aBasketInfo.asInstanceOf[ProductTypeInformation[A]].getFieldTypes()(0) should be theSameInstanceAs aInfo
   }