Merge pull request #9226 from uranusjr/new-resolver-skip-yanked-unles…

…s-only

Correctly implement yanking logic

news/9203.bugfix.rst

@@ -0,0 +1,2 @@
+New resolver: Correctly implement PEP 592. Do not return yanked versions from
+an index, unless the version range can only be satisfied by yanked candidates.

src/pip/_internal/resolution/resolvelib/factory.py

@@ -193,8 +193,17 @@ def iter_index_candidates():
                 specifier=specifier,
                 hashes=hashes,
             )
+            icans = list(result.iter_applicable())
+
+            # PEP 592: Yanked releases must be ignored unless only yanked
+            # releases can satisfy the version range. So if this is false,
+            # all yanked icans need to be skipped.
+            all_yanked = all(ican.link.is_yanked for ican in icans)
+
             # PackageFinder returns earlier versions first, so we reverse.
-            for ican in reversed(list(result.iter_applicable())):
+            for ican in reversed(icans):
+                if not all_yanked and ican.link.is_yanked:
+                    continue
                 yield self._make_candidate_from_link(
                     link=ican.link,
                     extras=extras,