fix errors during overridden update loop immediately crashing the game with no log entry

release-notes.md

@@ -15,6 +15,7 @@ See [log](https://github.com/Pathoschild/SMAPI/compare/1.12...1.13).
 
 For players:
 * SMAPI now recovers better from mod draw errors and detects when the error is irrecoverable.
+* SMAPI now recovers automatically from update errors if possible.
 * SMAPI now remembers if your game crashed and offers help next time you launch it.
 * Fixed installer finding redundant game paths on Linux.
 * Fixed save events not being raised after the first day on Linux/Mac.

src/StardewModdingAPI/Framework/Countdown.cs

@@ -0,0 +1,44 @@
+namespace StardewModdingAPI.Framework
+{
+    /// <summary>Counts down from a baseline value.</summary>
+    internal class Countdown
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The initial value from which to count down.</summary>
+        public int Initial { get; }
+
+        /// <summary>The current value.</summary>
+        public int Current { get; private set; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="initial">The initial value from which to count down.</param>
+        public Countdown(int initial)
+        {
+            this.Initial = initial;
+            this.Current = initial;
+        }
+
+        /// <summary>Reduce the current value by one.</summary>
+        /// <returns>Returns whether the value was decremented (i.e. wasn't already zero).</returns>
+        public bool Decrement()
+        {
+            if (this.Current <= 0)
+                return false;
+
+            this.Current--;
+            return true;
+        }
+        
+        /// <summary>Restart the countdown.</summary>
+        public void Reset()
+        {
+            this.Current = this.Initial;
+        }
+    }
+}

src/StardewModdingAPI/Framework/SGame.cs

@@ -30,15 +30,15 @@ namespace StardewModdingAPI.Framework
         ** SMAPI state
         ****/
         /// <summary>The maximum number of consecutive attempts SMAPI should make to recover from a draw error.</summary>
-        private readonly int MaxFailedDraws = 60; // roughly one second
+        private readonly Countdown DrawCrashTimer = new Countdown(60); // 60 ticks = roughly one second
+
+        /// <summary>The maximum number of consecutive attempts SMAPI should make to recover from an update error.</summary>
+        private readonly Countdown UpdateCrashTimer = new Countdown(60); // 60 ticks = roughly one second
 
         /// <summary>The number of ticks until SMAPI should notify mods that the game has loaded.</summary>
         /// <remarks>Skipping a few frames ensures the game finishes initialising the world before mods try to change it.</remarks>
         private int AfterLoadTimer = 5;
 
-        /// <summary>The number of consecutive failed draws.</summary>
-        private int FailedDraws;
-
         /// <summary>Whether the game is returning to the menu.</summary>
         private bool IsExiting;
 
@@ -233,6 +233,8 @@ namespace StardewModdingAPI.Framework
         /// <summary>The method called when the game is updating its state. This happens roughly 60 times per second.</summary>
         /// <param name="gameTime">A snapshot of the game timing state.</param>
         protected override void Update(GameTime gameTime)
+        {
+            try
             {
                 /*********
                 ** Skip conditions
@@ -316,7 +318,7 @@ namespace StardewModdingAPI.Framework
                 /*********
                 ** After load events
                 *********/
-            if (Context.IsSaveLoaded && !SaveGame.IsProcessing/*still loading save*/ && this.AfterLoadTimer >= 0)
+                if (Context.IsSaveLoaded && !SaveGame.IsProcessing /*still loading save*/ && this.AfterLoadTimer >= 0)
                 {
                     if (this.AfterLoadTimer == 0)
                     {
@@ -567,6 +569,18 @@ namespace StardewModdingAPI.Framework
                 this.KStatePrior = this.KStateNow;
                 for (PlayerIndex i = PlayerIndex.One; i <= PlayerIndex.Four; i++)
                     this.PreviouslyPressedButtons[(int)i] = this.GetButtonsDown(i);
+
+                this.UpdateCrashTimer.Reset();
+            }
+            catch (Exception ex)
+            {
+                // log error
+                this.Monitor.Log($"An error occured in the overridden update loop: {ex.GetLogSummary()}", LogLevel.Error);
+
+                // exit if irrecoverable
+                if (!this.UpdateCrashTimer.Decrement())
+                    this.Monitor.ExitGameImmediately("the game crashed when updating, and SMAPI was unable to recover the game.");
+            }
         }
 
         /// <summary>The method called to draw everything to the screen.</summary>
@@ -577,7 +591,7 @@ namespace StardewModdingAPI.Framework
             try
             {
                 this.DrawImpl(gameTime);
-                this.FailedDraws = 0;
+                this.DrawCrashTimer.Reset();
             }
             catch (Exception ex)
             {
@@ -585,12 +599,11 @@ namespace StardewModdingAPI.Framework
                 this.Monitor.Log($"An error occured in the overridden draw loop: {ex.GetLogSummary()}", LogLevel.Error);
 
                 // exit if irrecoverable
-                if (this.FailedDraws >= this.MaxFailedDraws)
+                if (!this.DrawCrashTimer.Decrement())
                 {
                     this.Monitor.ExitGameImmediately("the game crashed when drawing, and SMAPI was unable to recover the game.");
                     return;
                 }
-                this.FailedDraws++;
 
                 // abort in known unrecoverable cases
                 if (Game1.toolSpriteSheet?.IsDisposed == true)

src/StardewModdingAPI/StardewModdingAPI.csproj

@@ -121,6 +121,7 @@
     <Compile Include="Events\EventArgsStringChanged.cs" />
     <Compile Include="Events\GameEvents.cs" />
     <Compile Include="Events\GraphicsEvents.cs" />
+    <Compile Include="Framework\Countdown.cs" />
     <Compile Include="Framework\ModLoading\IModMetadata.cs" />
     <Compile Include="Framework\ModLoading\InvalidModStateException.cs" />
     <Compile Include="Framework\ModLoading\ModDependencyStatus.cs" />