RFC: Use a PackageFinder with ignore_compatibility when collecting …

…hashes

This fixes #4885

This is totally not ready to merge up yet, but I wanted to some early
feedback on this, as this is come I'm quite unfamiliar with.

Open questions:

1. Is "ignore_compatibility" really the right functionality to be using
   here? Hopefully it only ignores platform-related compatibility but
   not Python version?
2. I've made some minor changes here to vendored pip code to thread this
   `ignore_compatibility` parameter around. Is that ok?

TODO:

1. Actually write a unittest of this case if possible.

pipenv/patched/notpip/_internal/cli/req_command.py

@@ -430,6 +430,7 @@ def _build_package_finder(
         session: PipSession,
         target_python: Optional[TargetPython] = None,
         ignore_requires_python: Optional[bool] = None,
+        ignore_compatibility: bool = False,
     ) -> PackageFinder:
         """
         Create a package finder appropriate to this requirement command.
@@ -450,4 +451,5 @@ def _build_package_finder(
             link_collector=link_collector,
             selection_prefs=selection_prefs,
             target_python=target_python,
+            ignore_compatibility=ignore_compatibility,
         )

pipenv/patched/notpip/_internal/index/package_finder.py

@@ -628,6 +628,7 @@ def create(
         link_collector: LinkCollector,
         selection_prefs: SelectionPreferences,
         target_python: Optional[TargetPython] = None,
+        ignore_compatibility: bool=False,
     ) -> "PackageFinder":
         """Create a PackageFinder.
 
@@ -652,6 +653,7 @@ def create(
             allow_yanked=selection_prefs.allow_yanked,
             format_control=selection_prefs.format_control,
             ignore_requires_python=selection_prefs.ignore_requires_python,
+            ignore_compatibility=ignore_compatibility,
         )
 
     @property

pipenv/utils.py

@@ -428,6 +428,7 @@ def __init__(
         self._parsed_constraints = None
         self._resolver = None
         self._finder = None
+        self._ignore_compatibility_finder = None
         self._session = None
         self._constraint_file = None
         self._pip_options = None
@@ -798,6 +799,18 @@ def finder(self):
             )
         return self._finder
 
+    @property
+    def ignore_compatibility_finder(self):
+        from pipenv.vendor.pip_shims import shims
+        if self._ignore_compatibility_finder is None:
+            self._ignore_compatibility_finder = shims.get_package_finder(
+                install_cmd=self.pip_command,
+                options=self.pip_options,
+                session=self.session,
+                ignore_compatibility=False,
+            )
+        return self._ignore_compatibility_finder
+
     @property
     def parsed_constraints(self):
         from pipenv.vendor.pip_shims import shims
@@ -950,7 +963,7 @@ def collect_hashes(self, ireq):
             if hashes:
                 return hashes
 
-        applicable_candidates = self.finder.find_best_candidate(
+        applicable_candidates = self.ignore_compatibility_finder.find_best_candidate(
             ireq.name, ireq.specifier
         ).iter_applicable()
         return {

pipenv/vendor/pip_shims/compat.py

@@ -588,6 +588,7 @@ def get_package_finder(
     ignore_requires_python=None,  # type: Optional[bool]
     target_python_builder=None,  # type: Optional[TShimmedFunc]
     install_cmd_provider=None,  # type: Optional[TShimmedFunc]
+    ignore_compatibility=False,
 ):
     # type: (...) -> TFinder
     """Shim for compatibility to generate package finders.
@@ -693,6 +694,8 @@ def get_package_finder(
         and "ignore_requires_python" in builder_args.args
     ):
         build_kwargs["ignore_requires_python"] = ignore_requires_python
+
+    build_kwargs['ignore_compatibility'] = ignore_compatibility
     return install_cmd._build_package_finder(**build_kwargs)  # type: ignore