{"record":{"id":"2045b38c70ff9425","repo":"stride3d/stride","slug":"the-length-of-the-destination-data-buffer-is-larger-than-the","errorCode":null,"errorMessage":"The length of the destination data buffer is larger than the size of the Buffer","messagePattern":"The length of the destination data buffer is larger than the size of the Buffer","errorType":"exception","errorClass":"ArgumentException","httpStatus":null,"severity":"error","filePath":"sources/engine/Stride.Graphics/Buffer.cs","lineNumber":397,"sourceCode":"        /// <summary>\n        ///   Copies the content of the Buffer from GPU memory to a CPU memory pointer using a specific staging resource.\n        /// </summary>\n        /// <typeparam name=\"TData\">The type of the data to read from the Buffer.</typeparam>\n        /// <param name=\"commandList\">The <see cref=\"CommandList\"/>.</param>\n        /// <param name=\"stagingBuffer\">The staging buffer used to transfer the data from GPU memory.</param>\n        /// <param name=\"toData\">To destination span where the read data will be written.</param>\n        /// <exception cref=\"ArgumentException\">\n        ///   The length of the destination data buffer (<paramref name=\"toData\"/>) is larger than the size of the Buffer.\n        /// </exception>\n        /// <remarks>\n        ///   This method only works when called from the main thread that is accessing the main <see cref=\"GraphicsDevice\"/>.\n        /// </remarks>\n        public unsafe void GetData<TData>(CommandList commandList, Buffer stagingBuffer, Span<TData> toData) where TData : unmanaged\n        {\n            // Check destination buffer has valid size\n            int toDataSizeInBytes = toData.Length * sizeof(TData);\n            if (toDataSizeInBytes > SizeInBytes)\n                throw new ArgumentException(\"The length of the destination data buffer is larger than the size of the Buffer\");\n\n            // Copy the Buffer to a staging resource\n            if (!ReferenceEquals(this, stagingBuffer))\n                commandList.Copy(this, stagingBuffer);\n\n            // Map the staging resource to CPU-readable memory\n            var mappedResource = commandList.MapSubResource(stagingBuffer, subResourceIndex: 0, MapMode.Read);\n            var fromData = new ReadOnlySpan<TData>((void*) mappedResource.DataBox.DataPointer, toData.Length);\n            fromData.CopyTo(toData);\n            //Utilities.CopyWithAlignmentFallback(pointer, (void*)mappedResource.DataBox.DataPointer, (uint)toDataInBytes);\n            commandList.UnmapSubResource(mappedResource);\n        }\n\n        #endregion\n\n        #region SetData: Writing data into the Buffer\n\n        /// <summary>","sourceCodeStart":379,"sourceCodeEnd":415,"githubUrl":"https://github.com/stride3d/stride/blob/96fad776d210c221682aac1ccdf4c79dc046fc38/sources/engine/Stride.Graphics/Buffer.cs#L379-L415","documentation":"Buffer.GetData validates that the destination Span<TData>'s size in bytes does not exceed the GPU buffer's SizeInBytes before copying from a staging resource. Throwing ArgumentException here prevents reading past the end of the buffer into unrelated GPU-mapped memory.","triggerScenarios":"Calling buffer.GetData(commandList, stagingBuffer, span) where span.Length * sizeof(TData) > buffer.SizeInBytes, e.g. a Span<float> of 1024 elements read from a 2KB buffer or a larger element type than was uploaded.","commonSituations":"Buffer resized after the read code was written; reading a vertex buffer into a struct array with bigger stride; copying a partial buffer into a span sized for a larger buffer.","solutions":["Size the destination Span so its byte length is <= buffer.SizeInBytes.","Check buffer.SizeInBytes before the call and clamp/slice the span accordingly.","Recreate the buffer with a larger SizeInBytes if the data legitimately grew.","Verify the element type TData matches the type the buffer was created with."],"exampleFix":"// before\nvar data = new float[buffer.SizeInBytes]; // 4x too large in elements? actually larger than buffer\nbuffer.GetData(cmd, staging, data);\n// after\nvar data = new float[buffer.SizeInBytes / sizeof(float)];\nbuffer.GetData(cmd, staging, data.AsSpan());","handlingStrategy":"validation","validationCode":"if (toData.Length * sizeof(TData) > buffer.SizeInBytes)\n    throw new ArgumentException(\"Destination span too large for buffer\");","typeGuard":"bool CanReadInto<TData>(Buffer b, Span<TData> dst) where TData : unmanaged => dst.Length * sizeof(TData) <= b.SizeInBytes;","tryCatchPattern":"try { buffer.GetData(cmd, staging, span); }\ncatch (ArgumentException ex) when (ex.Message.Contains(\"destination data buffer\"))\n{\n    span = span.Slice(0, buffer.SizeInBytes / sizeof(TData));\n    buffer.GetData(cmd, staging, span);\n}","preventionTips":["Derive span sizes from buffer.SizeInBytes.","Recheck sizes after buffer reallocation.","Match TData to the buffer's element type."],"tags":["graphics","buffer","argument-validation","gpu"],"backgroundTag":"value-out-of-range","analyzedSha":"96fad776d210c221682aac1ccdf4c79dc046fc38","analyzedAt":"2026-09-14T02:59:31.279Z","contentChangedAt":"2026-09-14T02:59:31.279Z","schemaVersion":2},"datasetVersion":"2026-09-15T23:17:13.987Z"}