Make WheelBuilder should_unpack argument explicit

src/pip/_internal/commands/wheel.py

@@ -196,6 +196,7 @@ class WheelCommand(RequirementCommand):
                 )
                 build_failures = wb.build(
                     requirement_set.requirements.values(),
+                    should_unpack=False,
                 )
                 self.save_wheelnames(
                     [req.link.filename for req in

src/pip/_internal/wheel_builder.py

@@ -369,7 +369,7 @@ class WheelBuilder(object):
     def build(
         self,
         requirements,  # type: Iterable[InstallRequirement]
-        should_unpack=False  # type: bool
+        should_unpack,  # type: bool
     ):
         # type: (...) -> List[InstallRequirement]
         """Build wheels.

tests/unit/test_wheel_builder.py

@@ -193,7 +193,7 @@ class TestWheelBuilder(object):
 
         wheel_req = Mock(is_wheel=True, editable=False, constraint=False)
         with caplog.at_level(logging.INFO):
-            wb.build([wheel_req])
+            wb.build([wheel_req], should_unpack=False)
 
         assert "due to already being wheel" in caplog.text
         assert mock_build_one.mock_calls == []