Don't check for wheel when only build-system.requires is present (#11674)

Author: Jackenmen

news/11673.bugfix.rst

@@ -0,0 +1,3 @@
+Stop checking that ``wheel`` is present when ``build-system.requires``
+is provided without ``build-system.build-backend`` as ``setuptools``
+(which we still check for) will inject it anyway.

src/pip/_internal/pyproject.py

@@ -159,9 +159,8 @@ def load_pyproject_toml(
     if backend is None:
         # If the user didn't specify a backend, we assume they want to use
         # the setuptools backend. But we can't be sure they have included
-        # a version of setuptools which supplies the backend, or wheel
-        # (which is needed by the backend) in their requirements. So we
-        # make a note to check that those requirements are present once
+        # a version of setuptools which supplies the backend. So we
+        # make a note to check that this requirement is present once
         # we have set up the environment.
         # This is quite a lot of work to check for a very specific case. But
         # the problem is, that case is potentially quite common - projects that
@@ -170,6 +169,6 @@ def load_pyproject_toml(
         # tools themselves. The original PEP 518 code had a similar check (but
         # implemented in a different way).
         backend = "setuptools.build_meta:__legacy__"
-        check = ["setuptools>=40.8.0", "wheel"]
+        check = ["setuptools>=40.8.0"]
 
     return BuildSystemDetails(requires, backend, check, backend_path)