Decouple WheelBuilder from RequirementSet (#4860)

src/pip/_internal/commands/install.py

@@ -281,16 +281,15 @@ class InstallCommand(RequirementCommand):
                     if wheel and options.cache_dir:
                         # build wheels before install.
                         wb = WheelBuilder(
-                            requirement_set,
-                            finder,
-                            preparer,
-                            wheel_cache,
-                            build_options=[],
-                            global_options=[],
+                            finder, preparer, wheel_cache,
+                            build_options=[], global_options=[],
                         )
                         # Ignore the result: a failed wheel will be
                         # installed from the sdist/vcs whatever.
-                        wb.build(session=session, autobuilding=True)
+                        wb.build(
+                            requirement_set.requirements.values(),
+                            session=session, autobuilding=True
+                        )
 
                     installed = requirement_set.install(
                         install_options,

src/pip/_internal/commands/wheel.py

@@ -177,15 +177,14 @@ class WheelCommand(RequirementCommand):
                 try:
                     # build wheels
                     wb = WheelBuilder(
-                        requirement_set,
-                        finder,
-                        preparer,
-                        wheel_cache,
+                        finder, preparer, wheel_cache,
                         build_options=options.build_options or [],
                         global_options=options.global_options or [],
                         no_clean=options.no_clean,
                     )
-                    wheels_built_successfully = wb.build(session=session)
+                    wheels_built_successfully = wb.build(
+                        requirement_set.requirements.values(), session=session,
+                    )
                     if not wheels_built_successfully:
                         raise CommandError(
                             "Failed to build one or more wheels"

src/pip/_internal/wheel.py

@@ -657,9 +657,8 @@ class BuildEnvironment(object):
 class WheelBuilder(object):
     """Build wheels from a RequirementSet."""
 
-    def __init__(self, requirement_set, finder, preparer, wheel_cache,
+    def __init__(self, finder, preparer, wheel_cache,
                  build_options=None, global_options=None, no_clean=False):
-        self.requirement_set = requirement_set
         self.finder = finder
         self.preparer = preparer
         self.wheel_cache = wheel_cache
@@ -791,7 +790,7 @@ class WheelBuilder(object):
             logger.error('Failed cleaning build dir for %s', req.name)
             return False
 
-    def build(self, session, autobuilding=False):
+    def build(self, requirements, session, autobuilding=False):
         """Build wheels.
 
         :param unpack: If True, replace the sdist we built from with the
@@ -805,10 +804,8 @@ class WheelBuilder(object):
         )
         assert building_is_possible
 
-        reqset = self.requirement_set.requirements.values()
-
         buildset = []
-        for req in reqset:
+        for req in requirements:
             if req.constraint:
                 continue
             if req.is_wheel:

tests/unit/test_wheel.py

@@ -364,10 +364,10 @@ class TestWheelBuilder(object):
         with patch('pip._internal.wheel.WheelBuilder._build_one') \
                 as mock_build_one:
             wheel_req = Mock(is_wheel=True, editable=False, constraint=False)
-            reqset = Mock(requirements=Mock(values=lambda: [wheel_req]),
-                          wheel_download_dir='/wheel/dir')
-            wb = wheel.WheelBuilder(reqset, Mock(), Mock(), wheel_cache=None)
-            wb.build(Mock())
+            wb = wheel.WheelBuilder(
+                finder=Mock(), preparer=Mock(), wheel_cache=None,
+            )
+            wb.build([wheel_req], session=Mock())
             assert "due to already being wheel" in caplog.text
             assert mock_build_one.mock_calls == []