{"record":{"id":"4bbc99397e843875","repo":"pathwaycom/pathway","slug":"schema-without-argument-name-r-has-to-refer-to","errorCode":null,"errorMessage":"Schema.without() argument {name!r} has to refer to an existing column.","messagePattern":"Schema\\.without\\(\\) argument (.+?) has to refer to an existing column\\.","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"python/pathway/internals/schema.py","lineNumber":411,"sourceCode":"                    f\"Schema.with_types() argument name has to be an existing column name, received f{name}.\"\n                )\n            columns[name] = dataclasses.replace(columns[name], dtype=dt.wrap(dtype))\n\n        return schema_builder(columns=columns, id_dtype=self.id.dtype)\n\n    def without(self, *args: str | expr.ColumnReference) -> type[Schema]:\n        columns: dict[str, ColumnDefinition] = {\n            col.name: col.to_definition() for col in self.__columns__.values()\n        }\n        for arg in args:\n            if isinstance(arg, str):\n                name = arg\n            else:\n                name = arg._name\n            try:\n                columns.pop(name)\n            except KeyError:\n                raise ValueError(\n                    f\"Schema.without() argument {name!r} has to refer to an existing column.\"\n                )\n        return schema_builder(columns=columns, id_dtype=self.id.dtype)\n\n    def with_id_type(self, type, *, append_only: bool | None = None):\n        type = dt.wrap(type)\n        assert isinstance(type, dt.Pointer)\n        columns: dict[str, ColumnDefinition] = {\n            col.name: col.to_definition() for col in self.__columns__.values()\n        }\n        return schema_builder(\n            columns=columns, id_dtype=type, id_append_only=append_only\n        )\n\n    def update_properties(self, **kwargs) -> type[Schema]:\n        columns: dict[str, ColumnDefinition] = {\n            col.name: dataclasses.replace(col.to_definition(), **kwargs)\n            for col in self.__columns__.values()","sourceCodeStart":393,"sourceCodeEnd":429,"githubUrl":"https://github.com/pathwaycom/pathway/blob/fa2f74a4649b7c5908690cf60137263d8d80de5f/python/pathway/internals/schema.py#L393-L429","documentation":"Schema.without(*args) removes columns by name (plain str or ColumnReference). Each name is popped from the columns dict; a KeyError on pop means the schema has no such column, converted into this ValueError naming the offending argument.","triggerScenarios":"MySchema.without('user_id') when the column is called 'id' or 'userId'; also passing a ColumnReference whose _name belongs to a different table/schema.","commonSituations":"Trimming input schemas before a join or connector read; casing mismatches ('ID' vs 'id'); references taken from another table's column.","solutions":["List the schema's columns (MySchema.column_names()) and pass exact names.","When passing a ColumnReference, ensure it comes from this schema's columns (e.g. via MySchema columns or the corresponding table's pw.this).","Prefer without(pw.this.col) form inside table operations so names are checked against the right table."],"exampleFix":"# before\nS2 = MySchema.without('user_id')  # actual column: 'userId'\n\n# after\nS2 = MySchema.without('userId')","handlingStrategy":"validation","validationCode":"import pathway as pw\n\ndef without_args_valid(schema_cls, args) -> bool:\n    names = {a if isinstance(a, str) else a._name for a in args}\n    return names <= set(schema_cls.keys())","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Pass exact column names; verify with schema_cls.column_names() first.","Take ColumnReferences only from the schema/table being trimmed."],"tags":["pathway","schema","api-misuse","validation"],"backgroundTag":null,"analyzedSha":"fa2f74a4649b7c5908690cf60137263d8d80de5f","analyzedAt":"2026-08-15T01:48:17.006Z","schemaVersion":2},"datasetVersion":"2026-08-15T17:31:12.345Z"}