Merge pull request #11714 from uranusjr/strict-optional-free

Enable strict optional checking in PackageFinder

Author: pradyunsg

src/pip/_internal/index/package_finder.py

@@ -1,14 +1,11 @@
 """Routines related to PyPI, indexes"""
 
-# The following comment should be removed at some point in the future.
-# mypy: strict-optional=False
-
 import enum
 import functools
 import itertools
 import logging
 import re
-from typing import FrozenSet, Iterable, List, Optional, Set, Tuple, Union
+from typing import TYPE_CHECKING, FrozenSet, Iterable, List, Optional, Set, Tuple, Union
 
 from pip._vendor.packaging import specifiers
 from pip._vendor.packaging.tags import Tag
@@ -39,6 +36,9 @@
 from pip._internal.utils.packaging import check_requires_python
 from pip._internal.utils.unpacking import SUPPORTED_EXTENSIONS
 
+if TYPE_CHECKING:
+    from pip._vendor.typing_extensions import TypeGuard
+
 __all__ = ["FormatControl", "BestCandidateResult", "PackageFinder"]
 
 
@@ -251,7 +251,7 @@ def evaluate_link(self, link: Link) -> Tuple[LinkType, str]:
 
 def filter_unallowed_hashes(
     candidates: List[InstallationCandidate],
-    hashes: Hashes,
+    hashes: Optional[Hashes],
     project_name: str,
 ) -> List[InstallationCandidate]:
     """
@@ -540,6 +540,7 @@ def _sort_key(self, candidate: InstallationCandidate) -> CandidateSortingKey:
                 binary_preference = 1
             if wheel.build_tag is not None:
                 match = re.match(r"^(\d+)(.*)$", wheel.build_tag)
+                assert match is not None, "guaranteed by filename validation"
                 build_tag_groups = match.groups()
                 build_tag = (int(build_tag_groups[0]), build_tag_groups[1])
         else:  # sdist
@@ -942,43 +943,46 @@ def _format_versions(cand_iter: Iterable[InstallationCandidate]) -> str:
                 "No matching distribution found for {}".format(req)
             )
 
-        best_installed = False
-        if installed_version and (
-            best_candidate is None or best_candidate.version <= installed_version
-        ):
-            best_installed = True
+        def _should_install_candidate(
+            candidate: Optional[InstallationCandidate],
+        ) -> "TypeGuard[InstallationCandidate]":
+            if installed_version is None:
+                return True
+            if best_candidate is None:
+                return False
+            return best_candidate.version > installed_version
 
         if not upgrade and installed_version is not None:
-            if best_installed:
+            if _should_install_candidate(best_candidate):
                 logger.debug(
-                    "Existing installed version (%s) is most up-to-date and "
-                    "satisfies requirement",
+                    "Existing installed version (%s) satisfies requirement "
+                    "(most up-to-date version is %s)",
                     installed_version,
+                    best_candidate.version,
                 )
             else:
                 logger.debug(
-                    "Existing installed version (%s) satisfies requirement "
-                    "(most up-to-date version is %s)",
+                    "Existing installed version (%s) is most up-to-date and "
+                    "satisfies requirement",
                     installed_version,
-                    best_candidate.version,
                 )
             return None
 
-        if best_installed:
-            # We have an existing version, and its the best version
+        if _should_install_candidate(best_candidate):
             logger.debug(
-                "Installed version (%s) is most up-to-date (past versions: %s)",
-                installed_version,
+                "Using version %s (newest of versions: %s)",
+                best_candidate.version,
                 _format_versions(best_candidate_result.iter_applicable()),
             )
-            raise BestVersionAlreadyInstalled
+            return best_candidate
 
+        # We have an existing version, and its the best version
         logger.debug(
-            "Using version %s (newest of versions: %s)",
-            best_candidate.version,
+            "Installed version (%s) is most up-to-date (past versions: %s)",
+            installed_version,
             _format_versions(best_candidate_result.iter_applicable()),
         )
-        return best_candidate
+        raise BestVersionAlreadyInstalled
 
 
 def _find_name_version_sep(fragment: str, canonical_name: str) -> int:

src/pip/_internal/self_outdated_check.py

@@ -155,7 +155,7 @@ def was_installed_by_pip(pkg: str) -> bool:
 
 def _get_current_remote_pip_version(
     session: PipSession, options: optparse.Values
-) -> str:
+) -> Optional[str]:
     # Lets use PackageFinder to see what the latest pip version is
     link_collector = LinkCollector.create(
         session,
@@ -176,7 +176,7 @@ def _get_current_remote_pip_version(
     )
     best_candidate = finder.find_best_candidate("pip").best_candidate
     if best_candidate is None:
-        return
+        return None
 
     return str(best_candidate.version)
 
@@ -186,11 +186,14 @@ def _self_version_check_logic(
     state: SelfCheckState,
     current_time: datetime.datetime,
     local_version: DistributionVersion,
-    get_remote_version: Callable[[], str],
+    get_remote_version: Callable[[], Optional[str]],
 ) -> Optional[UpgradePrompt]:
     remote_version_str = state.get(current_time)
     if remote_version_str is None:
         remote_version_str = get_remote_version()
+        if remote_version_str is None:
+            logger.debug("No remote pip version found")
+            return None
         state.set(remote_version_str, current_time)
 
     remote_version = parse_version(remote_version_str)