User defined functions with reserved keyword names raise ParseError in BigQuery dialect

[sean-rose]

While BigQuery doesn't allow reserved keywords to be used as standalone identifiers unless they're quoted, it does allow unquoted reserved keywords to be used as part of a qualified identifier (e.g. a UDF qualified with its dataset, or a subfield qualified with its parent fields).

This was originally reported in #1535 "User defined functions with keyword or built in function names throw ParseError for BigQuery dialect" (though the code snippet there only demonstrated the built-in function case, not the keyword case).

Fully reproducible code snippet

sqlglot.parse_one("SELECT assert.true(1=1)", read="bigquery")

Official Documentation

• https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#path_expressions

  Subsequent parts of a path expression can include non-identifiers, such as reserved keywords.