{"record":{"id":"47221247d2d76a57","repo":"bevyengine/bevy","slug":"cannot-convert-vertexattributevalues-variant-to","errorCode":null,"errorMessage":"cannot convert VertexAttributeValues::{variant} to {into}","messagePattern":"cannot convert VertexAttributeValues::(.+?) to (.+?)","errorType":"exception","errorClass":"FromVertexAttributeError","httpStatus":null,"severity":"error","filePath":"crates/bevy_mesh/src/conversions.rs","lineNumber":32,"sourceCode":"//!\n//! // converting bevy_mesh::VertexAttributeValues to std::vec::Vec with two ways\n//! let result_into: Vec<[u32; 4]> = values.clone().try_into().unwrap();\n//! let result_from: Vec<[u32; 4]> = Vec::try_from(values.clone()).unwrap();\n//!\n//! // getting an error when trying to convert incorrectly\n//! let error: Result<Vec<u32>, _> = values.try_into();\n//!\n//! assert_eq!(buffer, result_into);\n//! assert_eq!(buffer, result_from);\n//! assert!(error.is_err());\n//! ```\n\nuse super::VertexAttributeValues;\nuse bevy_math::{IVec2, IVec3, IVec4, UVec2, UVec3, UVec4, Vec2, Vec3, Vec3A, Vec4};\nuse thiserror::Error;\n\n#[derive(Debug, Clone, Error)]\n#[error(\"cannot convert VertexAttributeValues::{variant} to {into}\")]\npub struct FromVertexAttributeError {\n    from: VertexAttributeValues,\n    variant: &'static str,\n    into: &'static str,\n}\n\nimpl FromVertexAttributeError {\n    fn new<T: 'static>(from: VertexAttributeValues) -> Self {\n        Self {\n            variant: from.enum_variant_name(),\n            into: core::any::type_name::<T>(),\n            from,\n        }\n    }\n}\n\nmacro_rules! impl_from {\n    ($from:ty, $variant:tt) => {","sourceCodeStart":14,"sourceCodeEnd":50,"githubUrl":"https://github.com/bevyengine/bevy/blob/396ca727080776bd313bb892423b7d94e03b81b4/crates/bevy_mesh/src/conversions.rs#L14-L50","documentation":"bevy_mesh implements TryFrom<VertexAttributeValues> for concrete Vec<T> types in crates/bevy_mesh/src/conversions.rs. Conversion succeeds only when the enum variant exactly matches the target component type (Float32x3 -> Vec<Vec3>, Uint32x3 -> Vec<UVec3>, and so on). Any other pairing returns FromVertexAttributeError, whose message names the stored variant and the requested target type.","triggerScenarios":"let positions: Vec<u32> = values.try_into()?; on VertexAttributeValues::Float32x3; requesting Vec<Vec2> from a Float32x3 attribute; requesting Vec<Vec4> from Unorm8x4 color data; reading Uint16-based data as Vec<u32>.","commonSituations":"Generic mesh-processing code that assumes one component type for all meshes; handling compressed (half-float/unorm) attributes as f32 vectors; mixing u16/u32 conventions when reading attributes from imported assets.","solutions":["Match on the VertexAttributeValues variant and read the concrete Vec inside it","Request the target type that matches VertexFormat::from(&values)","Use variant helpers such as VertexAttributeValues::as_float3() (crates/bevy_mesh/src/vertex.rs:460) for position data"],"exampleFix":"// before\nlet positions: Vec<Vec3> = values.try_into().unwrap(); // Err when variant != Float32x3\n\n// after\nlet positions: Option<&[[f32; 3]]> = values.as_float3();\nmatch positions {\n    Some(data) => use_positions(data),\n    None => warn!(?values, \"positions are not Float32x3\"),\n}","handlingStrategy":"try-catch","validationCode":"use bevy_mesh::VertexAttributeValues;\n\n// check the exact pairing before converting\nfn convertible_to_vec3(values: &VertexAttributeValues) -> bool {\n    matches!(values, VertexAttributeValues::Float32x3(_))\n}","typeGuard":"fn as_float3_slice(values: &VertexAttributeValues) -> Option<&[[f32; 3]]> {\n    values.as_float3() // Some only for the Float32x3 variant\n}","tryCatchPattern":"// inspect the variant instead of guessing a target type\nmatch values {\n    VertexAttributeValues::Float32x3(data) => { /* data: &Vec<[f32; 3]> */ }\n    VertexAttributeValues::Uint32x3(data) => { /* data: &Vec<[u32; 3]> */ }\n    other => warn!(?other, \"unsupported attribute variant\"),\n}","preventionTips":["Derive the target type from VertexFormat::from(&values) instead of hardcoding","Prefer the as_* accessors on VertexAttributeValues for known attributes","Match enum variants rather than try_into when meshes come from untrusted sources"],"tags":["bevy","bevy-mesh","rust","mesh","vertex-attributes","type-conversion"],"backgroundTag":"vertex-attribute-type-mismatch","analyzedSha":"396ca727080776bd313bb892423b7d94e03b81b4","analyzedAt":"2026-08-20T16:12:39.808Z","contentChangedAt":"2026-08-20T16:12:39.808Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}