Move markers check into the ireq->req constructor

This makes the check apply to ALL requirement constructions, no
exceptions.

Author: uranusjr

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

@@ -233,8 +233,14 @@ def find_candidates(self, requirements, constraint):
             if all(req.is_satisfied_by(c) for req in requirements)
         )
 
-    def make_requirement_from_install_req(self, ireq):
-        # type: (InstallRequirement) -> Requirement
+    def make_requirement_from_install_req(self, ireq, requested_extras):
+        # type: (InstallRequirement, Iterable[str]) -> Optional[Requirement]
+        if not ireq.match_markers(requested_extras):
+            logger.info(
+                "Ignoring %s: markers '%s' don't match your environment",
+                ireq.name, ireq.markers,
+            )
+            return None
         if not ireq.link:
             return SpecifierRequirement(ireq)
         cand = self._make_candidate_from_link(
@@ -253,7 +259,7 @@ def make_requirement_from_candidate(self, candidate):
     def make_requirement_from_spec(self, specifier, comes_from):
         # type: (str, InstallRequirement) -> Requirement
         ireq = self._make_install_req_from_spec(specifier, comes_from)
-        return self.make_requirement_from_install_req(ireq)
+        return self.make_requirement_from_install_req(ireq, ())
 
     def make_requirement_from_spec_matching_extras(
         self,
@@ -263,13 +269,7 @@ def make_requirement_from_spec_matching_extras(
     ):
         # type: (...) -> Optional[Requirement]
         ireq = self._make_install_req_from_spec(specifier, comes_from)
-        if not ireq.match_markers(requested_extras):
-            logger.info(
-                "Ignoring %s: markers '%s' don't match your environment",
-                ireq.name, ireq.markers,
-            )
-            return None
-        return self.make_requirement_from_install_req(ireq)
+        return self.make_requirement_from_install_req(ireq, requested_extras)
 
     def make_requires_python_requirement(self, specifier):
         # type: (Optional[SpecifierSet]) -> Optional[Requirement]

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

@@ -106,8 +106,6 @@ def resolve(self, root_reqs, check_supported_wheels):
         user_requested = set()  # type: Set[str]
         requirements = []
         for req in root_reqs:
-            if not req.match_markers():
-                continue
             if req.constraint:
                 # Ensure we only accept valid constraints
                 reject_invalid_constraint_types(req)
@@ -120,9 +118,11 @@ def resolve(self, root_reqs, check_supported_wheels):
             else:
                 if req.is_direct and req.name:
                     user_requested.add(canonicalize_name(req.name))
-                requirements.append(
-                    self.factory.make_requirement_from_install_req(req)
+                r = self.factory.make_requirement_from_install_req(
+                    req, requested_extras=(),
                 )
+                if r is not None:
+                    requirements.append(r)
 
         provider = PipProvider(
             factory=self.factory,