Unhandled exception when importing from a Postgres DB which doesn't have the postgis extension

[pfw]

Describe the bug

kart import dumps a stack trace rather than showing an error when importing from a Postgres DB which hasn't had `CREATE EXTENSION...' run.

To Reproduce
Steps to reproduce the behaviour:

1. Create a new PG database
2. Import some data eg. ogr2ogr -f PostgreSQL PG:dbname=data_gov_au mdb-boundaries.geojson
3. In an existing Kart repo try to import that table kart import postgresql://pfw:@localhost/data_gov_au mdb_boundaries
4. See error

If between step 1 and 2 create EXTENSION postgis; is run then it will complete correctly.

Expected behaviour
Kart should probably show an error on Postgis missing

Kart show allow importing (non-spatial) tables from PostgreSQL installs that don't have postGIS installed.

Output

Traceback (most recent call last):
  File "sqlalchemy/engine/base.py", line 1901, in _execute_context
  File "sqlalchemy/engine/default.py", line 732, in do_execute
psycopg2.errors.UndefinedFunction: function postgis_typmod_type(integer) does not exist
LINE 6:                 upper(postgis_typmod_type(A.atttypmod)) AS g...
                              ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "kart_cli.py", line 4, in <module>
  File "kart/cli.py", line 392, in entrypoint
  File "click/core.py", line 1130, in __call__
  File "click/core.py", line 1055, in main
  File "kart/cli_util.py", line 68, in invoke
  File "click/core.py", line 1657, in invoke
  File "click/core.py", line 1404, in invoke
  File "click/core.py", line 760, in invoke
  File "click/decorators.py", line 26, in new_func
  File "kart/tabular/import_.py", line 322, in import_
  File "kart/tabular/import_source.py", line 57, in check_valid
  File "kart/list_of_conflicts.py", line 91, in check_sources_are_importable
  File "kart/tabular/sqlalchemy_import_source.py", line 229, in meta_items
  File "kart/tabular/sqlalchemy_import_source.py", line 237, in meta_items_from_db
  File "kart/sqlalchemy/adapter/base.py", line 155, in all_v2_meta_items
  File "kart/utils.py", line 22, in wrapper
  File "kart/sqlalchemy/adapter/postgis.py", line 176, in all_v2_meta_items_including_empty
  File "sqlalchemy/orm/session.py", line 1712, in execute
  File "sqlalchemy/engine/base.py", line 1705, in _execute_20
  File "sqlalchemy/sql/elements.py", line 334, in _execute_on_connection
  File "sqlalchemy/engine/base.py", line 1582, in _execute_clauseelement
  File "sqlalchemy/engine/base.py", line 1944, in _execute_context
  File "sqlalchemy/engine/base.py", line 2125, in _handle_dbapi_exception
  File "sqlalchemy/util/compat.py", line 208, in raise_
  File "sqlalchemy/engine/base.py", line 1901, in _execute_context
  File "sqlalchemy/engine/default.py", line 732, in do_execute
sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedFunction) function postgis_typmod_type(integer) does not exist
LINE 6:                 upper(postgis_typmod_type(A.atttypmod)) AS g...
                              ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

[SQL: 
            SELECT
                C.column_name, C.ordinal_position, C.data_type, C.udt_name,
                C.character_maximum_length, C.numeric_precision, C.numeric_scale,
                PK.ordinal_position AS pk_ordinal_position,
                upper(postgis_typmod_type(A.atttypmod)) AS geometry_type,
                postgis_typmod_srid(A.atttypmod) AS geometry_srid
            FROM information_schema.columns C
            LEFT OUTER JOIN (
            SELECT KCU.* FROM information_schema.key_column_usage KCU
            INNER JOIN information_schema.table_constraints TC
            ON KCU.constraint_schema = TC.constraint_schema
            AND KCU.constraint_name = TC.constraint_name
            WHERE TC.constraint_type = 'PRIMARY KEY'
        ) PK
            ON (PK.table_schema = C.table_schema)
            AND (PK.table_name = C.table_name)
            AND (PK.column_name = C.column_name)
            LEFT OUTER JOIN pg_attribute A
            ON (A.attname = C.column_name)
            AND (A.attrelid = (%(table_identifier)s)::regclass::oid)
            WHERE C.table_schema=%(table_schema)s AND C.table_name=%(table_name)s
            ORDER BY C.ordinal_position;
        ]
[parameters: {'table_identifier': 'public.mdb_boundaries', 'table_schema': 'public', 'table_name': 'mdb_boundaries'}]
(Background on this error at: https://sqlalche.me/e/14/f405)
[48283] Failed to execute script 'kart_cli' due to unhandled exception!

Version Info

❯ kart --version
Kart v0.11.5, Copyright (c) Kart Contributors
» GDAL v3.4.0; PROJ v6.3.0
» PyGit2 v1.9.0; Libgit2 v1.4.2; Git v2.33.GIT
» SQLAlchemy v1.4.40; pysqlite3 v2.6.0/v3.31.1; SpatiaLite v5.0.1; Libpq v14.0.5
» SpatialIndex v1.9.3

[jhunjhunwala1234]

Hi, I would like to work on this bug. it would be great could you please assign this issue to me

[rcoup]

@jhunjhunwala1234 Great! Open a PR when you have something ready.