CI: Fix some mypy issues in backends (#2857)

ibis/backends/postgres/registry.py

@@ -239,7 +239,7 @@ def _string_agg(t, expr):
 
 
 # translate strftime spec into mostly equivalent PostgreSQL spec
-_scanner = re.Scanner(
+_scanner = re.Scanner(  # type: ignore # re does have a Scanner attribute
     # double quotes need to be escaped
     [('"', lambda scanner, token: r'\"')]
     + [
@@ -439,7 +439,7 @@ def _compile_regex_extract(element, compiler, **kw):
     return result
 
 
-def _regex_extract(t, expr):
+def _regex_extract_(t, expr):
     string, pattern, index = map(t.translate, expr.op().args)
     result = sa.case(
         [
@@ -652,7 +652,7 @@ def _day_of_week_name(t, expr):
         ops.RegexSearch: infix_op('~'),
         ops.RegexReplace: _regex_replace,
         ops.Translate: fixed_arity('translate', 3),
-        ops.RegexExtract: _regex_extract,
+        ops.RegexExtract: _regex_extract_,
         ops.StringSplit: fixed_arity(sa.func.string_to_array, 2),
         ops.StringJoin: _string_join,
         ops.FindInSet: _find_in_set,

ibis/backends/postgres/tests/conftest.py

@@ -15,7 +15,7 @@
 
 import os
 from pathlib import Path
-from typing import Optional
+from typing import Generator, Optional
 
 import pytest
 
@@ -76,6 +76,7 @@ def connect(data_directory: Path):
     def geo(self) -> Optional[ir.TableExpr]:
         if 'geo' in self.db.list_tables():
             return self.db.geo
+        return None
 
 
 def _random_identifier(suffix):
@@ -139,7 +140,7 @@ def translate():
 
 
 @pytest.fixture
-def temp_table(con) -> str:
+def temp_table(con) -> Generator[str, None, None]:
     """
     Return a temporary table name.
 

ibis/backends/postgres/udf.py

@@ -2,6 +2,7 @@
 import inspect
 import itertools
 from textwrap import dedent
+from typing import Any, Dict
 
 import sqlalchemy as sa
 from sqlalchemy.dialects.postgresql import dialect
@@ -17,7 +18,7 @@
 )
 from ibis.expr.signature import Argument as Arg
 
-_udf_name_cache = collections.defaultdict(itertools.count)
+_udf_name_cache: Dict[str, Any] = collections.defaultdict(itertools.count)
 
 
 class PostgresUDFError(IbisError):

ibis/backends/sqlite/tests/conftest.py

@@ -22,7 +22,7 @@ def connect(data_directory: Path):
                 'IBIS_TEST_SQLITE_DATABASE', data_directory / 'ibis_testing.db'
             )
         )
-        return ibis.sqlite.connect(str(path))
+        return ibis.sqlite.connect(str(path))  # type: ignore
 
     @property
     def functional_alltypes(self) -> ir.TableExpr:

ibis/backends/sqlite/tests/test_functions.py

@@ -9,17 +9,12 @@
 import pandas.testing as tm
 import pytest
 import sqlalchemy as sa
+from packaging.version import parse
 
-import ibis  # noqa: E402
-import ibis.config as config  # noqa: E402
-import ibis.expr.datatypes as dt  # noqa: E402
-from ibis import literal as L  # noqa: E402
-
-try:
-    from packaging.version import parse as get_version
-except ImportError:
-    from distutils.version import LooseVersion as get_version
-
+import ibis
+import ibis.expr.datatypes as dt
+from ibis import config
+from ibis import literal as L
 
 pytestmark = pytest.mark.sqlite
 
@@ -426,7 +421,7 @@ def test_category_label(alltypes, df):
 
 
 @pytest.mark.xfail(
-    get_version(sqlite3.sqlite_version) < get_version('3.8.3'),
+    parse(sqlite3.sqlite_version) < parse('3.8.3'),
     raises=sa.exc.OperationalError,
     reason='SQLite versions < 3.8.3 do not support the WITH statement',
 )