{"record":{"id":"27911608f70400e2","repo":"pathwaycom/pathway","slug":"incompatible-types-in-for-a-binary-operator-the-t","errorCode":null,"errorMessage":"Incompatible types in for a binary operator.\nThe types are: {left} and {right}. You might try casting the expressions to Any type to circumvent this, but this is most probably an error.","messagePattern":"Incompatible types in for a binary operator\\.\nThe types are: (.+?) and (.+?)\\. You might try casting the expressions to Any type to circumvent this, but this is most probably an error\\.","errorType":"exception","errorClass":"TypeError","httpStatus":null,"severity":"error","filePath":"python/pathway/internals/operator_mapping.py","lineNumber":204,"sourceCode":"\ntuple_handling_operators = {\n    operator.eq,\n    operator.ne,\n    operator.le,\n    operator.lt,\n    operator.ge,\n    operator.gt,\n}\n\n\ndef get_binary_operators_mapping(op, left, right):\n    if isinstance(left, dt.Array) and isinstance(right, dt.Array):\n        left, right = dt.coerce_arrays_pair(left, right)\n    if isinstance(left, dt.Pointer) and isinstance(right, dt.Pointer):\n        try:\n            dt.types_lca(left, right, raising=True)\n        except TypeError:\n            raise TypeError(\n                \"Incompatible types in for a binary operator.\\n\"\n                + f\"The types are: {left} and {right}. \"\n                + \"You might try casting the expressions to Any type to circumvent this,\"\n                + \" but this is most probably an error.\"\n            )\n    return _binary_operators_mapping.get(\n        (op, dt.normalize_dtype(left), dt.normalize_dtype(right))\n    )\n\n\ndef get_binary_expression(\n    left, right, op, left_dtype: dt.DType, right_dtype: dt.DType, default=None\n):\n    op_engine = _binary_operators_to_engine.get(op)\n    left_dtype_engine = left_dtype.to_engine()\n    right_dtype_engine = right_dtype.to_engine()\n    if op_engine is None:\n        return default","sourceCodeStart":186,"sourceCodeEnd":222,"githubUrl":"https://github.com/pathwaycom/pathway/blob/fa2f74a4649b7c5908690cf60137263d8d80de5f/python/pathway/internals/operator_mapping.py#L186-L222","documentation":"For binary operators (==, <, +, etc.) on pointer columns, Pathway computes the least common ancestor of the two pointer dtypes; when the two pointer types are unrelated (no common supertype other than mismatched generics), types_lca(raising=True) raises and the mapping layer converts it into this TypeError suggesting an explicit cast. The message text is slightly garbled ('Incompatible types in for a binary operator') but always concerns a binary operation between two incompatible Pointer dtypes.","triggerScenarios":"Comparing or joining-related operations between columns of different pointer types, e.g. table_a.some_id == table_b.other_id where one id is Pointer and the other is a different specialized pointer class; also comparisons between id columns of tables built with different with_id_type() schemas.","commonSituations":"Comparing ids from two differently-typed sources after with_id_type() was applied to one schema, or mixing pw.this.id with a pointer produced by a join/index_with on a differently typed table.","solutions":["Cast one side to a common type as the message suggests: pw.this.id.astype(pw.Pointer) or .astype(Any) on one operand.","Align id types at the source: build both tables with the same with_id_type(...) schema so their pointers share a type.","Re-check whether you actually want pointer equality — use table.join(...) / ix() for cross-table references instead of == on unrelated pointers."],"exampleFix":"# before\njoined = a.filter(a.ref_id == b_row.id)  # incompatible pointer types\n\n# after\njoined = a.filter(a.ref_id.astype(pw.Pointer) == b_row.id.astype(pw.Pointer))","handlingStrategy":"type-guard","validationCode":"from pathway.internals import dtype as dt\n\ndef pointers_compatible(l, r) -> bool:\n    if isinstance(l, dt.Pointer) and isinstance(r, dt.Pointer):\n        try:\n            dt.types_lca(l, r, raising=True)\n            return True\n        except TypeError:\n            return False\n    return True","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Build related tables from one schema (or with_types aligned) so id pointers share a type.","Cast pointer operands to pw.Pointer explicitly in cross-table comparisons."],"tags":["pathway","dtype","pointer","binary-operator","type-mismatch"],"backgroundTag":null,"analyzedSha":"fa2f74a4649b7c5908690cf60137263d8d80de5f","analyzedAt":"2026-08-15T01:48:17.006Z","schemaVersion":2},"datasetVersion":"2026-08-15T17:31:12.345Z"}