What causes "{e.Message}" in egametang/ET?

Inspect the chained InnerException (the original IOException) for the true cause.

egametang/ET · error · Exception

{e.Message}

Error message

{e.Message}

What it means

CompressTileCacheLayer wraps the underlying byte compression in a try/catch and rethrows any IOException as a generic Exception whose message is the original IOException's message (and chains it as inner). The thrown text is therefore the compressor/IO error verbatim, e.g. a buffer or stream failure from IRcCompressor.Compress. The real cause is an IO/compression failure during layer serialization.

Source

Thrown at Packages/cn.etetet.recast/Scripts/Core/Share/Detour.TileCache/DtTileCacheBuilder.cs:1931

            try
            {
                hw.Write(bw, layer.header, order, cCompatibility);
                int gridSize = layer.header.width * layer.header.height;
                byte[] buffer = new byte[gridSize * 3];
                for (int i = 0; i < gridSize; i++)
                {
                    buffer[i] = (byte)layer.heights[i];
                    buffer[gridSize + i] = (byte)layer.areas[i];
                    buffer[gridSize * 2 + i] = (byte)layer.cons[i];
                }

                var compressed = comp.Compress(buffer);
                bw.Write(compressed);
                return ms.ToArray();
            }
            catch (IOException e)
            {
                throw new Exception(e.Message, e);
            }
        }

        public byte[] CompressTileCacheLayer(DtTileCacheLayerHeader header, int[] heights, int[] areas, int[] cons, RcByteOrder order, bool cCompatibility, IRcCompressor comp)
        {
            using var ms = new MemoryStream();
            using var bw = new BinaryWriter(ms);
            DtTileCacheLayerHeaderWriter hw = new DtTileCacheLayerHeaderWriter();
            try
            {
                hw.Write(bw, header, order, cCompatibility);
                int gridSize = header.width * header.height;
                byte[] buffer = new byte[gridSize * 3];
                for (int i = 0; i < gridSize; i++)
                {
                    buffer[i] = (byte)heights[i];
                    buffer[gridSize + i] = (byte)areas[i];
                    buffer[gridSize * 2 + i] = (byte)cons[i];

View on GitHub (pinned to 5cab01f7a8)

Solutions

Inspect the chained InnerException (the original IOException) for the true cause.
Validate header.width*height and the heights/areas/cons array lengths equal gridSize before calling.
If using a custom IRcCompressor, ensure Compress never throws IOException on valid input.

Example fix

// before
byte[] bytes = builder.CompressTileCacheLayer(header, heights, areas, cons, order, cCompat, comp);

// after: validate inputs and surface the real cause
int gridSize = header.width * header.height;
if (heights.Length < gridSize || areas.Length < gridSize || cons.Length < gridSize)
    throw new InvalidOperationException("layer arrays smaller than width*height");
try { byte[] bytes = builder.CompressTileCacheLayer(header, heights, areas, cons, order, cCompat, comp); }
catch (Exception ex) { throw new InvalidOperationException("layer compress failed", ex.InnerException ?? ex); }

Defensive patterns

Strategy: try-catch

Validate before calling

int gridSize = header.width * header.height;
if (heights.Length < gridSize || areas.Length < gridSize || cons.Length < gridSize)
    throw new InvalidOperationException("layer arrays smaller than width*height");
byte[] bytes = builder.CompressTileCacheLayer(header, heights, areas, cons, order, cCompat, comp);

Try / catch

try { return builder.CompressTileCacheLayer(header, heights, areas, cons, order, cCompat, comp); }
catch (Exception e) { throw new InvalidDataException("layer compress failed", e.InnerException ?? e); }

Prevention

Always inspect ex.InnerException for the real IOException.
Validate header.width*height against array lengths first.
Confirm IRcCompressor.Compress is robust on valid input.

When it happens

Trigger: Calling CompressTileCacheLayer when IRcCompressor.Compress throws (bad buffer, unsupported format, or a custom compressor fault); writing to a MemoryStream that is closed/disposed.

Common situations: A custom IRcCompressor implementation raising IOException; malformed header (width*height producing wrong gridSize) feeding a too-small buffer; endianness/C-compat flag mismatch corrupting the stream mid-write.

Related errors

AI-assisted analysis of egametang/ET@5cab01f7a8 (2026-08-13). Data as JSON: /api/errors/01847ace1f1f34c4. Report an issue: GitHub.