fix(android): Parse java exception name when message missing

CHANGELOG.md

@@ -12,6 +12,9 @@
 
 ### Bug fixes
 
+* (Android) Fix error class and message parsing for uncaught Java exceptions
+  without message contents
+  [#159](https://github.com/bugsnag/bugsnag-unity/pull/159)
 * Show report metadata added using `Bugsnag.Metadata.Add()` in native crash
   reports
   [#157](https://github.com/bugsnag/bugsnag-unity/pull/157)

src/BugsnagUnity/Payload/Exception.cs

@@ -133,16 +133,28 @@ public static Exception FromUnityLogMessage(UnityLogMessage logMessage, System.D
       {
         var errorClass = match.Groups["errorClass"].Value;
         var message = match.Groups["message"].Value.Trim();
+        // Exceptions starting with "AndroidJavaException" are uncaught Java exceptions reported
+        // via the Unity log handler
         if (errorClass == AndroidJavaErrorClass)
         {
           match = Regex.Match(message, ErrorClassMessagePattern, RegexOptions.Singleline);
 
+          // If the message matches the "class: message" pattern, then the Java class is followed
+          // by a description of the Java exception. These two values will be used as the error
+          // class and message.
           if (match.Success)
           {
             errorClass = match.Groups["errorClass"].Value;
             message = match.Groups["message"].Value.Trim();
-            lines = new StackTrace(logMessage.StackTrace, StackTraceFormat.AndroidJava).ToArray();
           }
+          else
+          {
+            // There was no Java exception description, so the Java class is the only content in
+            // the message.
+            errorClass = message;
+            message = "";
+          }
+          lines = new StackTrace(logMessage.StackTrace, StackTraceFormat.AndroidJava).ToArray();
           handledState = HandledState.ForUnhandledException();
         }
         return new Exception(errorClass, message, lines, handledState);

tests/BugsnagUnity.Tests/ExceptionTests.cs

@@ -52,6 +52,28 @@ public void ParseExceptionFromLogMessage()
 
     [Test]
     public void ParseAndroidExceptionFromLogMessage()
+    {
+      string condition = "AndroidJavaException: java.lang.IllegalArgumentException";
+      string stacktrace = @"java.lang.IllegalArgumentException
+com.example.bugsnagcrashplugin.CrashHelper.UnhandledCrash(CrashHelper.java:11)
+com.unity3d.player.UnityPlayer.nativeRender(Native Method)";
+      var logType = UnityEngine.LogType.Error;
+      var log = new UnityLogMessage(condition, stacktrace, logType);
+      var exception = Exception.FromUnityLogMessage(log, new System.Diagnostics.StackFrame[] {}, Severity.Warning);
+      var stack = exception.StackTrace.ToList();
+      Assert.AreEqual("java.lang.IllegalArgumentException", exception.ErrorClass);
+      Assert.True(System.String.IsNullOrEmpty(exception.ErrorMessage));
+      Assert.AreEqual(2, stack.Count);
+      Assert.AreEqual("com.example.bugsnagcrashplugin.CrashHelper.UnhandledCrash()", stack[0].Method);
+      Assert.AreEqual("CrashHelper.java", stack[0].File);
+      Assert.AreEqual(11, stack[0].LineNumber);
+      Assert.AreEqual("com.unity3d.player.UnityPlayer.nativeRender()", stack[1].Method);
+      Assert.AreEqual("Native Method", stack[1].File);
+      Assert.AreEqual(null, stack[1].LineNumber);
+    }
+
+    [Test]
+    public void ParseAndroidExceptionAndMessageFromLogMessage()
     {
       string condition = "AndroidJavaException: java.lang.ArrayIndexOutOfBoundsException: length=2; index=2";
       string stacktrace = @"java.lang.ArrayIndexOutOfBoundsException: length=2; index=2