SNOW-846301: SnowflakeDialect.get_columns gives error for columns absent in ischema_names

[mayurinehate]

1. What version of Python are you using?

   Python 3.10.6

2. What operating system and processor architecture are you using?

   Linux-5.19.0-43-generic-x86_64-with-glibc2.35

3. What are the component versions in the environment (pip freeze)?

    snowflake-connector-python==3.0.4
    snowflake-sqlalchemy==1.4.7

4. What did you do?

from sqlalchemy import create_engine, inspect
engine = create_engine("snowflake://XXXX")
connection = engine.connect()
connection.execute("create table geospatial_table (id INTEGER, g GEOMETRY);")
inspector = inspect(connection)
columns = inspector.get_columns("geospatial_table")

5. What did you expect to see?

   Expected that program would return column details. Instead, received this error -

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/mayuri/.local/lib/python3.10/site-packages/snowflake/sqlalchemy/snowdialect.py", line 680, in get_columns
    schema_columns = self._get_schema_columns(connection, schema, **kw)
  File "<string>", line 2, in _get_schema_columns
  File "/home/mayuri/.local/lib/python3.10/site-packages/sqlalchemy/engine/reflection.py", line 47, in cache
    return fn(self, con, *args, **kw)
  File "/home/mayuri/.local/lib/python3.10/site-packages/snowflake/sqlalchemy/snowdialect.py", line 553, in _get_schema_columns
    type_instance = col_type(**col_type_kw)
TypeError: 'NullType' object is not callable

[sfc-gh-dszmolka]

hi and thank you for raising this issue with us and adding the reproduction is really appreciated! this seems to be working now

    columns = inspector.get_columns("geospatial_table")
    print(columns)

returns

[{'name': 'id', 'type': _CUSTOM_DECIMAL(precision=38, scale=0), 'nullable': True, 'default': None, 'autoincrement': False, 'comment': None, 'primary_key': False}, {'name': 'g', 'type': GEOMETRY(), 'nullable': True, 'default': None, 'autoincrement': False, 'comment': None, 'primary_key': False}]

closing for now but let us know please in a comment if you need further help with this