Fix searching serialized classes package contains multiple fragments

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/ClassDeserializer.kt

@@ -55,13 +55,8 @@ class ClassDeserializer(private val components: DeserializationComponents) {
         }
         else {
             val fragments = components.packageFragmentProvider.getPackageFragments(classId.packageFqName)
-            assert(fragments.size == 1) { "There should be exactly one package: $fragments, class id is $classId" }
-
-            val fragment = fragments.single()
-            if (fragment is DeserializedPackageFragment) {
-                // Similarly, verify that the containing package has information about this class
-                if (!fragment.hasTopLevelClass(classId.shortClassName)) return null
-            }
+            val fragment = fragments.firstOrNull { it !is DeserializedPackageFragment || it.hasTopLevelClass(classId.shortClassName) }
+                           ?: return null
 
             components.createContext(
                     fragment, nameResolver,

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/DeserializedClassDataFinder.kt

@@ -22,9 +22,12 @@ import org.jetbrains.kotlin.serialization.ClassDataWithSource
 
 class DeserializedClassDataFinder(private val packageFragmentProvider: PackageFragmentProvider) : ClassDataFinder {
     override fun findClassData(classId: ClassId): ClassDataWithSource? {
-        val packageFragment =
-                packageFragmentProvider.getPackageFragments(classId.packageFqName).singleOrNull()
-                        as? DeserializedPackageFragment ?: return null
-        return packageFragment.classDataFinder.findClassData(classId)
+        val packageFragments = packageFragmentProvider.getPackageFragments(classId.packageFqName)
+        for (fragment in packageFragments) {
+            if (fragment !is DeserializedPackageFragment) continue
+
+            fragment.classDataFinder.findClassData(classId)?.let { return it }
+        }
+        return null
     }
 }