[chalmerlowe]

Problem / Context

In GeoAlchemy2 >= 0.21.0, GenericFunction.__init__ wraps raw string arguments (isinstance(elem, str)) in an _UntypedString(NullType) bind parameter so PostgreSQL drivers send raw strings untyped.

In sqlalchemy-bigquery:

1. _fixup_st_arguments only overrides BindParameter.type for functions registered in _argument_types (which maps functions expecting GEOGRAPHY parameters). For geography constructor functions that accept a STRING argument (such as ST_GeogFromText), the BindParameter.type remains _UntypedString(NullType).
2. Furthermore, GeoAlchemy2 registers dialect-specific @compiles handlers (e.g., for "mssql") on GenericFunction subclasses such as ST_GeogFromText, giving those subclasses their own _compiler_dispatcher that shadows GenericFunction._compiler_dispatcher.

When BigQueryCompiler.visit_bindparam inspects a NullType bind parameter, it returns %(ST_GeogFromText_1)s without the :STRING type suffix, breaking sqlalchemy-bigquery's typed bind parameter contract and unit tests (test_geoalchemy2_core and test_calling_st_functions_that_dont_take_geographies).

Solution

• packages/sqlalchemy-bigquery/sqlalchemy_bigquery/geography.py:
  • In _fixup_st_arguments, restore argument.type = sqlalchemy.types.String() for any BindParameter whose type is NullType and whose value is a str prior to applying _argument_types overrides.
  • Recursively register _fixup_st_arguments across _get_all_subclasses(geoalchemy2.functions.GenericFunction) for the "bigquery" dialect so subclasses with their own _compiler_dispatcher invoke _fixup_st_arguments.
• packages/sqlalchemy-bigquery/tests/unit/test_geography.py:
  • Expanded test_fixup_st_arguments to verify that NullType bind parameters with str values are coerced to String(), while NullType bind parameters with non-string values (None) remain NullType.
  • Added test_nested_generic_function_subclasses_register_compiler to verify recursive subclass discovery and compiler dispatcher registration.
  • See CI results for test verification.

[gemini-code-assist]

Code Review

This pull request updates the BigQuery geography compiler to support GeoAlchemy2 >= 0.21.0 by restoring the String type for string bind parameters wrapped in NullType, and registers the fixup hook on all GenericFunction subclasses. The review feedback recommends wrapping the subclass registration in a try-except block to prevent import errors in environments where geoalchemy2 is not installed.