Address review comments

src/pip/_internal/build_env.py

@@ -67,7 +67,7 @@ class BuildEnvironment(object):
         self._temp_dir.cleanup()
 
 
-class FakeBuildEnvironment(BuildEnvironment):
+class NoOpBuildEnvironment(BuildEnvironment):
     def __enter__(self):
         pass
 

src/pip/_internal/operations/prepare.py

@@ -25,7 +25,7 @@ from pip._internal.utils.ui import open_spinner
 from pip._internal.vcs import vcs
 from pip._internal.req.req_install import InstallRequirement
 from pip._internal.index import FormatControl
-from pip._internal.build_env import FakeBuildEnvironment
+from pip._internal.build_env import NoOpBuildEnvironment
 
 logger = logging.getLogger(__name__)
 
@@ -113,6 +113,9 @@ class IsSDist(DistAbstraction):
         return dist
 
     def prep_for_dist(self, finder):
+        # Before calling "setup.py egg_info", we need to set-up the build
+        # environment.
+        
         build_requirements, isolate = self.req.get_pep_518_info()
 
         if 'setuptools' not in build_requirements:
@@ -122,11 +125,9 @@ class IsSDist(DistAbstraction):
                 "upgrade to a newer version of pip.")
 
         if not isolate:
-            self.req.build_environment = FakeBuildEnvironment(no_clean=False)
+            self.req.build_env = NoOpBuildEnvironment(no_clean=False)
 
-        with self.req.build_environment as prefix:
-            # Ignore the --no-binary option when installing the build system, so
-            # we don't recurse trying to build a self-hosting build system.
+        with self.req.build_env as prefix:
             if isolate:
                 _install_build_reqs(finder, prefix, build_requirements)
 

src/pip/_internal/req/req_install.py

@@ -129,7 +129,7 @@ class InstallRequirement(object):
         self.prepared = False
 
         self.isolated = isolated
-        self.build_environment = BuildEnvironment(no_clean=True)
+        self.build_env = BuildEnvironment(no_clean=True)
 
     @classmethod
     def from_editable(cls, editable_req, comes_from=None, isolated=False,
@@ -882,7 +882,7 @@ class InstallRequirement(object):
             rmtree(self.source_dir)
         self.source_dir = None
         self._temp_build_dir.cleanup()
-        self.build_environment.cleanup()
+        self.build_env.cleanup()
 
     def install_editable(self, install_options,
                          global_options=(), prefix=None):

src/pip/_internal/resolve.py

@@ -187,7 +187,7 @@ class Resolver(object):
 
         if req.editable:
             return self.preparer.prepare_editable_requirement(
-                req, self.require_hashes, self.finder
+                req, self.require_hashes, self.finder,
             )
 
         # satisfied_by is only evaluated by calling _check_skip_installed,