{"record":{"id":"5b82253165b9b88f","repo":"wasmerio/wasmer","slug":"getting-invalid-type-from-table-handle-this-error","errorCode":null,"errorMessage":"getting invalid type from table, handle this error","messagePattern":"getting invalid type from table, handle this error","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"lib/vm/src/table.rs","lineNumber":245,"sourceCode":"        // update table definition\n        unsafe {\n            let mut td_ptr = self.get_vm_table_definition();\n            let td = td_ptr.as_mut();\n            td.current_elements = new_len;\n            td.base = self.vec.as_mut_ptr() as _;\n        }\n        Some(size)\n    }\n\n    /// Get reference to the specified element.\n    ///\n    /// Returns `None` if the index is out of bounds.\n    pub fn get(&self, index: u32) -> Option<TableElement> {\n        let raw_data = self.vec.get(index as usize).cloned()?;\n        Some(match self.table.ty {\n            ValType::ExternRef => TableElement::ExternRef(unsafe { raw_data.extern_ref }),\n            ValType::FuncRef => TableElement::FuncRef(unsafe { raw_data.func_ref }),\n            _ => todo!(\"getting invalid type from table, handle this error\"),\n        })\n    }\n\n    /// Set reference to the specified element.\n    ///\n    /// # Errors\n    ///\n    /// Returns an error if the index is out of bounds.\n    pub fn set(&mut self, index: u32, reference: TableElement) -> Result<(), Trap> {\n        self.set_with_construction(index, reference, false)\n    }\n\n    pub(crate) fn set_with_construction(\n        &mut self,\n        index: u32,\n        reference: TableElement,\n        in_construction: bool,\n    ) -> Result<(), Trap> {","sourceCodeStart":227,"sourceCodeEnd":263,"githubUrl":"https://github.com/wasmerio/wasmer/blob/8c4b9ee9d33fb2068863fbb3d328683e7e6ff7f5/lib/vm/src/table.rs#L227-L263","documentation":"Table::get reads the raw table element and matches on the table's declared ValType; only ExternRef and FuncRef are handled. Any other ValType (should be impossible for a reference table) hits `todo!` — a defensive panic meant to be replaced with a proper error if invalid table types ever occur.","triggerScenarios":"Calling Table::get (directly or via table.copy's copy_within) on a table whose `table.ty` is neither ExternRef nor FuncRef, or on a table whose type descriptor got corrupted/misinitialized so the ValType match falls through.","commonSituations":"Embedders constructing tables programmatically (via Table::new with a Type carrying an unexpected ValType) rather than through wasm validation; fuzzing or memory corruption producing an out-of-contract table type; a wasmer version where table types were extended without updating this match.","solutions":["Only create tables via validated wasm or with Type limited to funcref/externref element types","Replace the todo! with a returned error/internal assertion so misuse surfaces as TableError instead of a panic","Audit embedder code that constructs Table/Type manually and fix the element ValType","Upgrade wasmer if a newly supported reference type needs handling here"],"exampleFix":"// before\n_ => todo!(\"getting invalid type from table, handle this error\"),\n// after\n_ => return None, // or record unreachable: tables may only hold references","handlingStrategy":"type-guard","validationCode":"// validate table element type before creating/accessing\nfn table_type_is_reference(ty: &ValType) -> bool {\n    matches!(ty, ValType::ExternRef | ValType::FuncRef)\n}","typeGuard":"fn elem_type_ok(table_type: &TableType) -> bool {\n    matches!(table_type.ty, ValType::ExternRef | ValType::FuncRef)\n}","tryCatchPattern":"// Table::get panics rather than returning Result; wrap table creation instead\nlet table = Table::new(store, TableType { ty: ValType::FuncRef, ..ty })?; // validated upstream\n// then get() can only see FuncRef/ExternRef","preventionTips":["Construct tables only via validated wasm imports/exports, not hand-built ValTypes","Validate TableType.ty is funcref/externref before Table::new","Update the match if new reference types (e.g. exnref) are introduced","Prefer API paths that return TableError over raw accessors"],"tags":["tables","wasm","runtime"],"backgroundTag":"invalid-table-element-type","analyzedSha":"8c4b9ee9d33fb2068863fbb3d328683e7e6ff7f5","analyzedAt":"2026-09-01T23:06:31.009Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-09T06:17:21.866Z"}