Postgres imports: Hide postgis internal views

Re #434

Hides these views/tables from `kart import '<postgres-url>'`:

```
 extname | extschema |      relname      | relkind
---------+-----------+-------------------+---------
 postgis | public    | spatial_ref_sys   | r
 postgis | public    | geography_columns | v
 postgis | public    | geometry_columns  | v
 postgis | public    | raster_columns    | v
 postgis | public    | raster_overviews  | v
```

These aren't importable things and they just cause potential problems,
especially when used with `--all-tables` (but they are noisy when
listing/prompting for tables also)

CHANGELOG.md

@@ -20,6 +20,7 @@ _When adding new entries to the changelog, please include issue/PR numbers where
 * A few bugfixes involving accurately roundtripping boolean and blob types through different working copy types.
 * Bugfix: 3D and 4D geometries are now properly roundtripped through SQL Server working copy.
 * Fix help text for discarding changes to refer to `kart restore` instead of `kart reset`, as `kart restore` is now the simplest way to discard changes. [#426](https://github.com/koordinates/kart/issues/426)
+* `import`: PostGIS internal views/tables are no longer listed by `--list` or imported by `--all-tables`, and can't be imported by name either. [#439](https://github.com/koordinates/kart/issues/439)
 
 ### Calculating feature counts for diffs
 

kart/sqlalchemy/postgis.py

@@ -31,31 +31,34 @@ def _on_checkout(dbapi_connection, connection_record, connection_proxy):
     @classmethod
     def list_tables(cls, sess, db_schema=None):
         if db_schema is not None:
-            r = sess.execute(
-                sqlalchemy.text(
-                    """
-                    SELECT table_name as name,
-                    obj_description(format('%s.%s', table_schema, table_name)::regclass::oid, 'pg_class') as title
-                    FROM information_schema.tables WHERE table_schema = :db_schema
-                    ORDER BY name;
-                    """
-                ),
-                {"db_schema": db_schema},
-            )
+            name_clause = "c.relname"
+            schema_clause = "n.nspname = :db_schema"
+            params = {"db_schema": db_schema}
         else:
-            r = sess.execute(
-                sqlalchemy.text(
-                    """
-                    SELECT format('%s.%s', table_schema, table_name) as name,
-                    obj_description(format('%s.%s', table_schema, table_name)::regclass::oid, 'pg_class') as title
-                    FROM information_schema.tables
-                    WHERE table_schema NOT IN ('information_schema', 'pg_catalog', 'tiger', 'topology')
-                    ORDER BY name;
-                    """
-                )
-            )
+            name_clause = "format('%s.%s', n.nspname, c.relname)"
+            schema_clause = "n.nspname NOT IN ('information_schema', 'pg_catalog', 'tiger', 'topology')"
+            params = {}
 
-        return {row['name']: row['title'] for row in r}
+        r = sess.execute(
+            sqlalchemy.text(
+                f"""
+                SELECT {name_clause} as name, obj_description(c.oid, 'pg_class') as title
+                FROM pg_catalog.pg_class c
+                    INNER JOIN pg_namespace n ON n.oid = c.relnamespace
+                WHERE c.relkind IN ('r', 'v') AND {schema_clause}
+                AND c.oid NOT IN (
+                    SELECT d.objid
+                    FROM pg_catalog.pg_extension AS e
+                        INNER JOIN pg_catalog.pg_depend AS d ON (d.refobjid = e.oid)
+                    WHERE d.deptype = 'e'
+                    AND e.extname = 'postgis'
+                )
+                ORDER BY {name_clause};
+                """
+            ),
+            params,
+        )
+        return {row["name"]: row["title"] for row in r}
 
     @classmethod
     def db_schema_searchpath(cls, sess):

kart/sqlalchemy_import_source.py

@@ -155,10 +155,10 @@ def validate_table(self, table):
         if table in all_tables:
             if (
                 self.db_schema is None
-                and '.' in table
+                and "." in table
                 and self.db_type is not DbType.GPKG
             ):
-                db_schema, table = table.split('.', maxsplit=1)
+                db_schema, table = table.split(".", maxsplit=1)
                 return db_schema, table
             else:
                 return self.db_schema, table

tests/test_import_source.py

@@ -2,6 +2,8 @@
 
 from osgeo import gdal
 
+import pytest
+
 from kart.ogr_import_source import postgres_url_to_ogr_conn_str
 from kart.repo import KartRepo
 
@@ -15,8 +17,8 @@ def _dataset_col_types(dataset):
     return cols
 
 
-def test_import_various_field_types(tmp_path, postgis_db, cli_runner):
-    # Using postgres here because it has the best type preservation
+@pytest.fixture
+def postgres_table_with_types(postgis_db):
     with postgis_db.connect() as conn:
         conn.execute(
             """
@@ -38,6 +40,17 @@ def test_import_various_field_types(tmp_path, postgis_db, cli_runner):
                 );
                 """
         )
+    yield
+    with postgis_db.connect() as conn:
+        conn.execute(
+            """
+            DROP TABLE IF EXISTS typoes;
+            """
+        )
+
+
+def test_import_various_field_types(tmp_path, postgres_table_with_types, cli_runner):
+    # Using postgres here because it has the best type preservation
 
     r = cli_runner.invoke(["init", str(tmp_path / "repo1")])
     assert r.exit_code == 0, r.stderr
@@ -115,3 +128,20 @@ def test_import_various_field_types(tmp_path, postgis_db, cli_runner):
         "reel": {"dataType": "float", "size": 64},
         "tumeric": {"dataType": "float", "size": 64},
     }
+
+
+def test_list_postgres_tables(postgis_db, postgres_table_with_types, cli_runner):
+    r = cli_runner.invoke(["import", "--list", os.environ["KART_POSTGRES_URL"]])
+    assert r.exit_code == 0, r.stderr
+
+    # NOTE: these tables are intentionally absent:
+    # '  public.geography_columns',
+    # '  public.geometry_columns',
+    # '  public.spatial_ref_sys',
+    assert r.stdout.splitlines() == ["Tables found:", "  public.typoes"]
+
+    r = cli_runner.invoke(
+        ["import", "--list", os.environ["KART_POSTGRES_URL"] + "/public"]
+    )
+    assert r.exit_code == 0, r.stderr
+    assert r.stdout.splitlines() == ["Tables found:", "  typoes"]