fix: paginator generator nullability bug caused by documents (#1155)

Author: 0marperez

.changes/f71f083b-6e5f-4a3c-9069-464b1f9f6d36.json

@@ -0,0 +1,5 @@
+{
+    "id": "f71f083b-6e5f-4a3c-9069-464b1f9f6d36",
+    "type": "bugfix",
+    "description": "Fix paginator generator `List<*>` & `Map.Entry<String, *>` nullability"
+}

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/core/KotlinSymbolProvider.kt

@@ -166,7 +166,7 @@ class KotlinSymbolProvider(private val model: Model, private val settings: Kotli
         val fullyQualifiedKeyType = keyReference.fullName
 
         val valueReference = toSymbol(shape.value)
-        val valueSuffix = if (valueReference.isNullable) "?" else ""
+        val valueSuffix = if (valueReference.isNullable || shape.isSparse) "?" else ""
         val valueType = "${valueReference.name}$valueSuffix"
         val fullyQualifiedValueType = "${valueReference.fullName}$valueSuffix"
 

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/rendering/PaginatorGenerator.kt

@@ -272,18 +272,22 @@ private fun getItemDescriptorOrNull(paginationInfo: PaginationInfo, ctx: Codegen
     val itemMember = ctx.model.expectShape(itemMemberId)
     val isSparse = itemMember.isSparse
     val (collectionLiteral, targetMember) = when (itemMember) {
-        is MapShape ->
-            ctx.symbolProvider.toSymbol(itemMember)
-                .expectProperty(SymbolProperty.ENTRY_EXPRESSION) as String to itemMember
-        is CollectionShape ->
-            ctx.symbolProvider.toSymbol(ctx.model.expectShape(itemMember.member.target)).name to ctx.model.expectShape(
-                itemMember.member.target,
-            )
+        is MapShape -> {
+            val symbol = ctx.symbolProvider.toSymbol(itemMember)
+            val entryExpression = symbol.expectProperty(SymbolProperty.ENTRY_EXPRESSION) as String
+            entryExpression to itemMember
+        }
+        is CollectionShape -> {
+            val target = ctx.model.expectShape(itemMember.member.target)
+            val symbol = ctx.symbolProvider.toSymbol(target)
+            val literal = symbol.name + if (symbol.isNullable || isSparse) "?" else ""
+            literal to target
+        }
         else -> error("Unexpected shape type ${itemMember.type}")
     }
 
     return ItemDescriptor(
-        collectionLiteral + if (isSparse) "?" else "",
+        collectionLiteral,
         targetMember,
         itemLiteral,
         itemPathLiteral,