my.hypothesis: better mypy coverage

my/core/compat.py

@@ -1,6 +1,8 @@
 '''
 Some backwards compatibility stuff/deprecation helpers
 '''
+from types import ModuleType
+
 from . import warnings
 from .common import LazyLogger
 
@@ -13,7 +15,7 @@ def pre_pip_dal_handler(
         e: ModuleNotFoundError,
         cfg,
         requires=[],
-) -> None:
+) -> ModuleType:
     '''
     https://github.com/karlicoss/HPI/issues/79
     '''

my/core/error.py

@@ -4,7 +4,7 @@ See https://beepb00p.xyz/mypy-error-handling.html#kiss for more detail
 """
 
 from itertools import tee
-from typing import Union, TypeVar, Iterable, List, Tuple, Type, Optional
+from typing import Union, TypeVar, Iterable, List, Tuple, Type, Optional, Callable, Any
 
 
 T = TypeVar('T')
@@ -44,7 +44,7 @@ def split_errors(l: Iterable[ResT[T, E]], ET: Type[E]) -> Tuple[Iterable[T], Ite
     return (values, errors)
 
 
-def sort_res_by(items: Iterable[ResT], key) -> List[ResT]:
+def sort_res_by(items: Iterable[Res[T]], key: Callable[[T], Any]) -> List[Res[T]]:
     """
     The general idea is: just alaways carry errors with the entry that precedes them
     """
@@ -58,7 +58,7 @@ def sort_res_by(items: Iterable[ResT], key) -> List[ResT]:
             groups.append((i, group))
             group = []
 
-    results = []
+    results: List[Res[T]] = []
     for v, errs in sorted(groups, key=lambda p: key(p[0])):
         results.extend(errs)
         results.append(v)
@@ -125,7 +125,7 @@ def extract_error_datetime(e: Exception) -> Optional[datetime]:
     return None
 
 
-def test_datetime_errors():
+def test_datetime_errors() -> None:
     import pytz
     dt_notz = datetime.now()
     dt_tz   = datetime.now(tz=pytz.timezone('Europe/Amsterdam'))

my/hypothesis.py

@@ -2,7 +2,8 @@
 [[https://hypothes.is][Hypothes.is]] highlights and annotations
 """
 from dataclasses import dataclass
-from typing import Optional
+from datetime import datetime
+from typing import Optional, Callable
 
 from .core import Paths
 
@@ -50,12 +51,17 @@ def _dal() -> dal.DAL:
 
 
 def highlights() -> List[Res[Highlight]]:
-    return sort_res_by(_dal().highlights(), key=lambda h: h.created)
+    # todo hmm. otherwise mypy complans
+    key: Callable[[Highlight], datetime] = lambda h: h.created
+    return sort_res_by(_dal().highlights(), key=key)
 
 
 # TODO eh. always provide iterators? although sort_res_by could be neat too...
 def pages() -> List[Res[Page]]:
-    return sort_res_by(_dal().pages(), key=lambda h: h.created)
+    # note: mypy report shows "No Anys on this line here", apparently a bug with type aliases
+    # https://github.com/python/mypy/issues/8594
+    key: Callable[[Page], datetime] = lambda h: h.created
+    return sort_res_by(_dal().pages(), key=key)
 
 
 # todo not public api yet
@@ -67,12 +73,12 @@ def stats():
     }
 
 
-def _main():
+def _main() -> None:
     for page in get_pages():
         print(page)
 
 if __name__ == '__main__':
     _main()
 
-get_highlights = highlights # TODO deprecate
-get_pages = pages # TODO deprecate
+get_highlights = highlights # todo deprecate
+get_pages = pages # todo deprecate