Fix zero length matches

Grepl.Tests/Commands/BasicCommands.cs

@@ -627,5 +627,24 @@ public void Should_30_show_only_file_name_replace_save()
 
 		}
 
+		[TestMethod]
+		public void Should_10_exclude_zero_length_match()
+		{
+			File.WriteAllText("test.txt", "abc\n");
+
+			var r = GreplEntry(".*", "-r");
+			Assert.AreEqual(0, r.Code);
+
+			var raw = r.Output;
+			var exp = @"
+test.txt
+abc
+";
+
+			CompareDetails(exp, raw);
+
+			Assert.AreEqual(exp, raw);
+
+		}
 	}
 }

Grepl/Executor.cs

@@ -269,6 +269,10 @@ void Process(string file, bool printFileName, Dictionary<ColoredMessage, Capture
 				// var currentlnStart = -2; // initially unknown
 				foreach (Match match in matches)
 				{
+					if (match.Length == 0)
+					{
+						continue; // ignore zero-length matches and prevent index out of range when index >= length (zero length match at the end of a string)
+					}
 					// find the start of the line
 					var lineStart = body.LastIndexOf('\n', match.Index);
 					lineStart++;