Fix various Flake8 issues in the codebase (#43)

This patch fixes various Flake8 issues in the codebase to make the 
Github Actions CI closer to passing. Issues were related to whitespace,
unused imports, bad indentation, etc.

Most missing imports were caused by typing annotations that were only 
in comments. I upgraded those to actual type annotations when Tox was 
complaining, except for a few __all__ instances: I really don't think 
there is a large benefit from using strong typing for the __all__ 
module variable.

Author: ldionne

lnt/__init__.py

@@ -3,11 +3,4 @@
 __versioninfo__ = (0, 4, 2)
 __version__ = '.'.join(map(str, __versioninfo__)) + '.dev0'
 
-# lnt module is imported from the setup script before modules are installed so
-# modules might not be available.
-try:
-    from typing import Sequence
-except Exception:
-    pass
-
-__all__ = []  # type: Sequence[str]
+__all__ = []

lnt/formats/__init__.py

@@ -11,9 +11,9 @@
 from .PlistFormat import format as plist
 from .JSONFormat import format as json
 
-formats = [plist, json]  # type: List[Dict]
-formats_by_name = dict((f['name'], f) for f in formats)  # type: Dict[str, Dict]
-format_names = list(formats_by_name.keys())  # type: List[str]
+formats: List[Dict] = [plist, json]
+formats_by_name: Dict[str, Dict] = dict((f['name'], f) for f in formats)
+format_names: List[str] = list(formats_by_name.keys())
 
 
 def get_format(name):

lnt/server/__init__.py

@@ -1,3 +1 @@
-from typing import Sequence
-
-__all__ = []  # type: Sequence[str]
+__all__ = []

lnt/server/db/__init__.py

@@ -1,3 +1 @@
-from typing import Sequence
-
-__all__ = []  # type: Sequence[str]
+__all__ = []

lnt/server/db/fieldchange.py

@@ -27,8 +27,7 @@ def post_submit_tasks(session, ts, run_id):
     regenerate_fieldchanges_for_run(session, ts, run_id)
 
 
-def delete_fieldchange(session, ts, change):
-    # type: (Session, TestSuiteDB, TestSuiteDB.FieldChange) -> List[int]
+def delete_fieldchange(session: Session, ts: TestSuiteDB, change: TestSuiteDB.FieldChange) -> List[int]:
     """Delete this field change.  Since it might be attahed to a regression
     via regression indicators, fix those up too.  If this orphans a regression
     delete it as well."""
@@ -64,8 +63,7 @@ def delete_fieldchange(session, ts, change):
 
 
 @timed
-def regenerate_fieldchanges_for_run(session, ts, run_id):
-    # type: (Session, TestSuiteDB, int) -> None
+def regenerate_fieldchanges_for_run(session: Session, ts: TestSuiteDB, run_id: int) -> None:
     """Regenerate the set of FieldChange objects for the given run.
     """
     # Allow for potentially a few different runs, previous_runs, next_runs
@@ -213,8 +211,7 @@ def is_overlaping(fc1, fc2):
            (r1_min < r2_max and r2_min < r1_max)
 
 
-def percent_similar(a, b):
-    # type: (str, str) -> float
+def percent_similar(a: str, b: str) -> float:
     """
     Percent similar: are these strings similar to each other?
     :param a: first string
@@ -225,8 +222,10 @@ def percent_similar(a, b):
 
 
 @timed
-def identify_related_changes(session, ts, fc, active_changes):
-    # type: (Session, TestSuiteDB, TestSuiteDB.FieldChange, List) -> Tuple[bool, List]
+def identify_related_changes(session: Session,
+                             ts: TestSuiteDB,
+                             fc: TestSuiteDB.FieldChange,
+                             active_changes: List) -> Tuple[bool, List]:
     """Can we find a home for this change in some existing regression? If a
     match is found add a regression indicator adding this change to that
     regression, otherwise create a new regression for this change.

lnt/server/db/migrations/upgrade_2_to_3.py

@@ -46,7 +46,7 @@ def upgrade_testsuite(engine, session, name):
     # Grab Test Suite.
     test_suite = session.query(upgrade_0_to_1.TestSuite).\
                  filter_by(name=name).first()
-    assert(test_suite is not None)
+    assert test_suite is not None
 
     # Add FieldChange to the test suite.
     Base = add_fieldchange(test_suite)

lnt/server/db/migrations/upgrade_7_to_8.py

@@ -87,7 +87,7 @@ def upgrade_testsuite(engine, session, name):
     # Grab Test Suite.
     test_suite = session.query(upgrade_0_to_1.TestSuite).\
                  filter_by(name=name).first()
-    assert(test_suite is not None)
+    assert test_suite is not None
 
     # Add FieldChange to the test suite.
     Base = add_regressions(test_suite)

lnt/server/db/rules/__init__.py

@@ -1,3 +1 @@
-from typing import Sequence
-
-__all__ = []  # type: Sequence[str]
+__all__ = []

lnt/server/db/rules/rule_update_fixed_regressions.py

@@ -34,8 +34,7 @@ def is_fixed(session, ts, regression):
     return all(fixes)
 
 
-def impacts(session, ts, run_id, regression):
-    # type: (Session, TestSuiteDB, int, TestSuiteDB.Regression) -> bool
+def impacts(session: Session, ts: TestSuiteDB, run_id: int, regression: TestSuiteDB.Regression) -> bool:
     """Does this run have a chance of impacting this regression?
 
     This is just to prevent doing a full comparison, so we don't have
@@ -51,8 +50,7 @@ def impacts(session, ts, run_id, regression):
     return machine_id in regression_machines_set
 
 
-def age_out_oldest_regressions(session, ts, num_to_keep=50):
-    # type: (Session, TestSuiteDB, int) -> int
+def age_out_oldest_regressions(session: Session, ts: TestSuiteDB, num_to_keep: int = 50) -> int:
     """Find the oldest regressions that are still in the detected state,
     and age them out.  This is needed when regressions are not manually
     acknowledged, regression analysis can grow unbounded.
@@ -69,7 +67,7 @@ def age_out_oldest_regressions(session, ts, num_to_keep=50):
         .join(ts.FieldChange) \
         .all()
 
-    regression_newest_change = {}  # type: Dict[int, int]
+    regression_newest_change: Dict[int, int] = {}
     for regression_id, order_id in regression_orders:
         current = regression_newest_change.get(regression_id)
         if current is None or current < order_id:

lnt/server/db/rules_manager.py

@@ -49,12 +49,12 @@ def load_rules():
 
 
 # Places our rules can hook to.
-HOOKS = {
+HOOKS: Dict['str', List[Callable]] = {
     'post_test_hook': [],
     'post_submission_hook': [],
     'post_regression_create_hook': [],
     'is_useful_change': [],
-}  # type: Dict['str', List[Callable]]
+}
 
 DESCRIPTIONS = {}
 HOOKS_LOADED = False