From 6b5e83ce1de2072d9efee1b89b18eaef0235b7ec Mon Sep 17 00:00:00 2001
From: Starlight220 <53231611+Starlight220@users.noreply.github.com>
Date: Fri, 13 Nov 2020 21:06:46 +0200
Subject: [PATCH] [wpilibj] DrivetrainSim: Initialize m_u to default value
 (#2854)

m_u wasn't being initialized, so if user called update() before setInputs() the program would crash with an NPE.
---
 .../wpi/first/wpilibj/simulation/DifferentialDrivetrainSim.java  | 1 +
 1 file changed, 1 insertion(+)

diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/DifferentialDrivetrainSim.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/DifferentialDrivetrainSim.java
index 2e608bc36c..ab3d003d1c 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/DifferentialDrivetrainSim.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/DifferentialDrivetrainSim.java
@@ -98,6 +98,7 @@ public class DifferentialDrivetrainSim {
     m_currentGearing = m_originalGearing;
 
     m_x = new Matrix<>(Nat.N7(), Nat.N1());
+    m_u = VecBuilder.fill(0, 0);
   }
 
   /**