1 files changed, 76 insertions, 0 deletions
diff --git a/src/SMAPI.Internal/ExceptionHelper.cs b/src/SMAPI.Internal/ExceptionHelper.cs
new file mode 100644
index 00000000..4bc55f95
--- /dev/null
+++ b/src/SMAPI.Internal/ExceptionHelper.cs
@@ -0,0 +1,76 @@
+using System;
+using System.Reflection;
+using System.Text.RegularExpressions;
+
+namespace StardewModdingAPI.Internal
+{
+    /// <summary>Provides extension methods for handling exceptions.</summary>
+    internal static class ExceptionHelper
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Get a string representation of an exception suitable for writing to the error log.</summary>
+        /// <param name="exception">The error to summarize.</param>
+        public static string GetLogSummary(this Exception exception)
+        {
+            try
+            {
+                string message;
+                switch (exception)
+                {
+                    case TypeLoadException ex:
+                        message = $"Failed loading type '{ex.TypeName}': {exception}";
+                        break;
+
+                    case ReflectionTypeLoadException ex:
+                        string summary = ex.ToString();
+                        foreach (Exception childEx in ex.LoaderExceptions ?? new Exception[0])
+                            summary += $"\n\n{childEx?.GetLogSummary()}";
+                        message = summary;
+                        break;
+
+                    default:
+                        message = exception?.ToString() ?? $"<null exception>\n{Environment.StackTrace}";
+                        break;
+                }
+
+                return ExceptionHelper.SimplifyExtensionMessage(message);
+            }
+            catch (Exception ex)
+            {
+                throw new InvalidOperationException($"Failed handling {exception?.GetType().FullName} (original message: {exception?.Message})", ex);
+            }
+        }
+
+        /// <summary>Get the lowest exception in an exception stack.</summary>
+        /// <param name="exception">The exception from which to search.</param>
+        public static Exception GetInnermostException(this Exception exception)
+        {
+            while (exception.InnerException != null)
+                exception = exception.InnerException;
+            return exception;
+        }
+
+        /// <summary>Simplify common patterns in exception log messages that don't convey useful info.</summary>
+        /// <param name="message">The log message to simplify.</param>
+        public static string SimplifyExtensionMessage(string message)
+        {
+            // remove namespace for core exception types
+            message = Regex.Replace(
+                message,
+                @"(?:StardewModdingAPI\.Framework\.Exceptions|Microsoft\.Xna\.Framework|System|System\.IO)\.([a-zA-Z]+Exception):",
+                "$1:"
+            );
+
+            // remove unneeded root build paths for SMAPI and Stardew Valley
+            message = message
+                .Replace(@"C:\source\_Stardew\SMAPI\src\", "")
+                .Replace(@"C:\GitlabRunner\builds\Gq5qA5P4\0\ConcernedApe\", "");
+
+            // remove placeholder info in Linux/macOS stack traces
+            return message
+                .Replace(@"<filename unknown>:0", "");
+        }
+    }
+}