CameraX PreviewView in RelativeLayout goes beyond the bounds - android-studio

Question

I have an XML file that is a RelativeLayout with two children: a PreviewView and a LinearLayout like so:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".MainActivity">
<RelativeLayout
android:layout_width="200dp"
android:layout_height="200dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.camera.view.PreviewView
android:id="#+id/preview_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="10px"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/border"
android:orientation="vertical">
</LinearLayout>
</RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
border.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<stroke android:width="5dip" android:color="#android:color/white" />
</shape>
The LinearLayout is intended to overlay the PreviewView and show a border. But the PreviewView seems to go beyond the size LinearLayout even though both have the match_parent constraint. How do I constrain it to actually match_parent?
These are dependencies i am using:
// Barcode model dependencies
implementation 'com.google.mlkit:barcode-scanning:16.1.0'
// CameraX dependencies
implementation "androidx.camera:camera-camera2:1.0.0-rc01"
implementation "androidx.camera:camera-lifecycle:1.0.0-rc01"
implementation "androidx.camera:camera-view:1.0.0-alpha20"