bevyengine/bevy · error

Data buffer should exist if we're in the fast path

Error message

Data buffer should exist if we're in the fast path

What it means

Internal invariant expect in the bindless fast path: a Data-buffer binding range was encountered for a bindless slot whose data buffer was never created, indicating the descriptor tables and allocator disagree.

Source

Thrown at crates/bevy_render/src/material_bind_groups.rs:1584

                // Ignore all resources other than data.
                UnpreparedBindingResource::Buffer(_)
                | UnpreparedBindingResource::ShaderBuffer(_)
                | UnpreparedBindingResource::TextureView(..)
                | UnpreparedBindingResource::Sampler(..) => {}

                UnpreparedBindingResource::Data(data_range) => {
                    // Ignore this resource unless it represents data we're
                    // responsible for.
                    let Some(binding_index) =
                        bindless_index_table.get_binding(bind_group_slot, bindless_index)
                    else {
                        continue;
                    };

                    // Poke the new data into the buffer.
                    self.data_buffers
                        .get_mut(&bindless_index)
                        .expect("Data buffer should exist if we're in the fast path")
                        .set(
                            binding_index,
                            &unprepared_bind_group.data_buffer
                                [(data_range.start as usize)..(data_range.end as usize)],
                        );
                }
            }
        }
    }

    /// Recreates the bind group and bindless index table buffer if necessary.
    fn prepare(
        &mut self,
        render_device: &RenderDevice,
        pipeline_cache: &PipelineCache,
        label: &'static str,
        bind_group_layout: &BindGroupLayoutDescriptor,
        fallback_bindless_resources: &FallbackBindlessResources,

View on GitHub (pinned to 396ca72708)

Solutions

1. Report as a Bevy engine bug with a reproducing project
2. Re-check material binding descriptors for consistency

When it happens

Trigger: Thrown at crates/bevy_render/src/material_bind_groups.rs:1584 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@396ca72708 (2026-08-20). Data as JSON: /api/errors/0695872a5cafd24f. Report an issue: GitHub.