A failed start is decided in RunStart.Launch; the scene steps nothing without a live run

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Assets/Scripts/Gameplay/ActionGameManager.cs

@@ -854,21 +854,12 @@ public class ActionGameManager : MonoBehaviour
         var scenario = PendingScenario;
         PendingScenario = null;
         var failures = new List<string>();
-        RunStart.Staged staged = null;
-        try
+        var staged = RunStart.Launch(() => RunSave.Replace(CultCache, () =>
         {
-            staged = RunSave.Replace(CultCache, () =>
-            {
-                RunStart.GenerateArena(ItemManager, Settings.ZoneSettings, Settings.PlanetSettings, CurrentGalaxy, scenario);
-                PopulateLevel(CurrentGalaxy.Entrance);
-                return RunStart.Stage(ItemManager, Zone, scenario, Settings.StartingHullName, Settings.TutorialGenerationSettings, failures);
-            });
-        }
-        catch (Exception exception)
-        {
-            Debug.LogException(exception);
-            failures.Add(exception.Message);
-        }
+            RunStart.GenerateArena(ItemManager, Settings.ZoneSettings, Settings.PlanetSettings, CurrentGalaxy, scenario);
+            PopulateLevel(CurrentGalaxy.Entrance);
+            return RunStart.Stage(ItemManager, Zone, scenario, Settings.StartingHullName, Settings.TutorialGenerationSettings, failures);
+        }), failures, Debug.LogException);
 
         if (staged == null)
         {
@@ -1348,6 +1339,8 @@ public class ActionGameManager : MonoBehaviour
 
     void Update()
     {
+        // No live run (a start that failed, a run that ended): the main menu is up, and nothing steps a zone or reads a player.
+        if (CurrentGalaxy == null) return;
         if(!_paused)
         {
             _time += Time.deltaTime;

Assets/Scripts/ServerShared/RunStart.cs

@@ -30,6 +30,21 @@ public static class RunStart
             itemManager, zoneSettings, planetSettings, galaxy, galaxy.Entrance, galaxy.IsPrelude, scenario.Ambient);
     }
 
+    // Runs a start and answers whether it produced a run: null, with the reason in `failures`, when `start` throws or
+    // returns nothing. The caller shows the failure and clears its run; nothing past a null may run the game.
+    public static Staged Launch(Func<Staged> start, List<string> failures, Action<Exception> log = null)
+    {
+        Staged staged = null;
+        try { staged = start(); }
+        catch (Exception exception)
+        {
+            log?.Invoke(exception);
+            failures.Add(exception.Message);
+        }
+        if (staged == null && failures.Count == 0) failures.Add("the start produced no run");
+        return staged;
+    }
+
     // Runs the scenario's Stage, then admits its player and everything it placed: each entity's stance set both ways
     // with the player, a pilot for each piloted one. Returns null, with every failure listed and the arena unchanged,
     // unless the whole scenario staged.

tests/Aetheria.Shared.Tests/RunLaunchTests.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+// RunStart.Launch decides whether a start produced a run; the game scene halts on its answer (a failed start clears the
+// galaxy, and a scene with no galaxy steps nothing). Kills: a start that throws or returns nothing reading as a run, a
+// failure with no reason to show on the menu, a thrown exception that is neither logged nor listed, and a start that
+// worked being reported failed.
+public sealed class RunLaunchTests
+{
+    [Fact]
+    public void AStartThatThrowsIsNoRunAndSaysWhy()
+    {
+        var failures = new List<string>();
+        var logged = new List<Exception>();
+        var staged = RunStart.Launch(() => throw new InvalidOperationException("the arena would not generate"), failures, logged.Add);
+        Assert.Null(staged);
+        Assert.Equal(new[] { "the arena would not generate" }, failures);
+        Assert.Single(logged);
+    }
+
+    [Fact]
+    public void AStartThatReturnsNothingIsNoRunAndKeepsItsOwnReasons()
+    {
+        var failures = new List<string>();
+        Assert.Null(RunStart.Launch(() => { failures.Add("player: the scenario places no player"); return null; }, failures));
+        Assert.Equal(new[] { "player: the scenario places no player" }, failures);
+    }
+
+    [Fact]
+    public void AStartThatReturnsNothingAndSaysNothingStillGivesAReason()
+    {
+        var failures = new List<string>();
+        Assert.Null(RunStart.Launch(() => null, failures));
+        Assert.Single(failures);
+    }
+
+    [Fact]
+    public void AStartThatStagedIsARunWithNoFailures()
+    {
+        var failures = new List<string>();
+        var made = new RunStart.Staged();
+        Assert.Same(made, RunStart.Launch(() => made, failures));
+        Assert.Empty(failures);
+    }
+}