Merge pull request #569 from studioph/435-print-line-on-failed-plugin…

…s-parse

Print line number and offending entry on plugins parse failure

Mutagen.Bethesda.Core.UnitTests/Plugins/Order/PluginListingsParserTests.cs

@@ -73,4 +73,22 @@ public void CommentTrimming()
             new LoadOrderListing("ModB.esp", false),
             new LoadOrderListing("ModC.esp", true));
     }
+
+    [Fact]
+    public void PrintLinesOnFailure()
+    {
+        var parser = new PluginListingsParser(
+            new PluginListingCommentTrimmer(),
+            new LoadOrderListingParser(
+                new HasEnabledMarkersInjection(true)));
+
+        parser.Invoking(p => p.Parse(GetStream(
+@"*ModA.esm
+ModB.esp
+*Malformed"))
+            .ToList())
+            .Should()
+            .Throw<InvalidDataException>()
+            .WithMessage("Load order file had malformed entry at line 3: \"*Malformed\"");
+    }
 }

Mutagen.Bethesda.Core/Plugins/Order/DI/PluginListingsParser.cs

@@ -30,13 +30,23 @@ public PluginListingsParser(
     /// <inheritdoc />
     public IEnumerable<ILoadOrderListingGetter> Parse(Stream stream)
     {
+        uint currentLine = 0;
         using var streamReader = new StreamReader(stream);
         while (!streamReader.EndOfStream)
         {
+            currentLine++;
             var str = streamReader.ReadLine().AsSpan();
             str = _commentTrimmer.Trim(str);
             if (MemoryExtensions.IsWhiteSpace(str) || str.Length == 0) continue;
-            yield return _listingParser.FromString(str);
+
+            if (_listingParser.TryFromString(str, out var listing))
+            {
+                yield return listing;
+            }
+            else
+            {
+                throw new InvalidDataException($"Load order file had malformed entry at line {currentLine}: \"{str}\"");
+            }
         }
     }
 }