From f5755cc4af67355e3a986714fac08088034dbf56 Mon Sep 17 00:00:00 2001
From: JoePfeiffer <joseph@pfeifferfamily.net>
Date: Thu, 11 Jan 2024 09:30:41 -0700
Subject: [PATCH] Add explicit test and abort for "no stages defined" running
 simulation

---
 core/resources/l10n/messages.properties           |  3 +++
 .../sf/openrocket/logging/SimulationAbort.java    |  3 +++
 .../simulation/BasicEventSimulationEngine.java    | 15 +++++++++++++--
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/core/resources/l10n/messages.properties b/core/resources/l10n/messages.properties
index 8467d4d03..7a3f369da 100644
--- a/core/resources/l10n/messages.properties
+++ b/core/resources/l10n/messages.properties
@@ -655,8 +655,11 @@ BasicEventSimulationEngine.error.noConfiguredIgnition = No motors configured to
 BasicEventSimulationEngine.error.noIgnition = No motors ignited.
 BasicEventSimulationEngine.error.NaNResult = Simulation resulted in not-a-number (NaN) value, please report a bug.
 
+BasicEventSimlationEngine.nullBranchName = (null)
+
 RK4SimulationStepper.error.valuesTooLarge = Simulation values exceeded limits.  Try selecting a shorter time step.
 
+SimulationAbort.noActiveStages = No active stages
 SimulationAbort.noMotorsDefined = No motors defined in the simulation
 SimulationAbort.noConfiguredIgnition = No motors configured to ignite at liftoff
 SimulationAbort.noIgnition = No motors ignited
diff --git a/core/src/net/sf/openrocket/logging/SimulationAbort.java b/core/src/net/sf/openrocket/logging/SimulationAbort.java
index e692c3f4a..7f1ed6ccd 100644
--- a/core/src/net/sf/openrocket/logging/SimulationAbort.java
+++ b/core/src/net/sf/openrocket/logging/SimulationAbort.java
@@ -24,6 +24,9 @@ public class SimulationAbort extends Message {
 	 * Possible causes of sim aborts
 	 */
 	public enum Cause {
+		// No active stages in simulation
+		NO_ACTIVE_STAGES(trans.get("SimulationAbort.noActiveStages")),
+		
 		// No motors are defined in the sim configuration
 		NOMOTORSDEFINED(trans.get("SimulationAbort.noMotorsDefined")),
 
diff --git a/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java b/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java
index d169c9595..107ed4eff 100644
--- a/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java
+++ b/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java
@@ -75,8 +75,14 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 		simulationConfig.copyStages(origConfig);	// Clone the stage activation configuration
 		
 		currentStatus = new SimulationStatus(simulationConfig, simulationConditions);
-		// main simulation branch 
-		final String branchName = simulationConfig.getRocket().getTopmostStage(currentStatus.getConfiguration()).getName();
+		// main simulation branch. Need to watch for pathological case with no stages defined
+		final AxialStage topStage = simulationConfig.getRocket().getTopmostStage(currentStatus.getConfiguration());
+		final String branchName;
+			if (topStage != null) {
+				branchName = topStage.getName();
+			} else {
+				branchName = trans.get("BasicEventSimulationEngine.nullBranchName");
+			}
 		FlightDataBranch initialBranch = new FlightDataBranch( branchName, FlightDataType.TYPE_TIME);
 
 		// put a point on it so we can plot if we get an early abort event
@@ -90,6 +96,11 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 
 		// Problems that keep us from simulating at all
 
+		// No active stages
+		if (topStage == null) {
+			currentStatus.abortSimulation(SimulationAbort.Cause.NO_ACTIVE_STAGES);
+		}
+		
 		// No motors in configuration
 		if (!simulationConfig.hasMotors() ) {
 			currentStatus.abortSimulation(SimulationAbort.Cause.NOMOTORSDEFINED);