Add always-install-via-wheel feature flag

docs/html/cli/pip_install.rst

@@ -315,8 +315,9 @@ Per-requirement Overrides
 -------------------------
 
 Since version 7.0 pip supports controlling the command line options given to
-``setup.py`` via requirements files. This disables the use of wheels (cached or
-otherwise) for that package, as ``setup.py`` does not exist for wheels.
+``setup.py`` via requirements files.  Unless the ``always-install-via-wheel``
+feature is enabled, this disables the use of wheels (cached or otherwise),
+as ``setup.py`` does not exist for wheels.
 
 The ``--global-option`` and ``--install-option`` options are used to pass
 options to ``setup.py``. For example:
@@ -334,6 +335,10 @@ script as:
 
    python setup.py --no-user-cfg install --prefix='/usr/local' --no-compile
 
+When the ``always-install-via-wheel`` feature is enabled, ``--install-option``
+is ignored, and ``--global-option`` is passed to the ``setup.py bdist_wheel``
+command that is used to create a wheel that will be installed.
+
 Note that the only way of giving more than one option to ``setup.py``
 is through multiple ``--global-option`` and ``--install-option``
 options, as shown in the example above. The value of each option is

news/9778.feature.rst

@@ -0,0 +1,6 @@
+Add an ``always-install-via-wheel`` feature flag. When enabled, ``--no-binary``
+no longer implies using the legacy ``setup.py install`` path, and instead
+a wheel is built locally before installing. ``--build-option`` and
+``--global-option`` are now passed to ``setup.py bdist_wheel`` in ``pip
+install``, as it was already done in ``pip wheel``. ``--install-option`` is
+ignored (because there is no ``setup.py install`` involved).

src/pip/_internal/cli/cmdoptions.py

@@ -501,12 +501,15 @@ def no_binary():
         callback=_handle_no_binary,
         type="str",
         default=format_control,
-        help="Do not use binary packages. Can be supplied multiple times, and "
+        help="Do not download binary packages nor use the wheel cache. "
+        "Can be supplied multiple times, and "
         'each time adds to the existing value. Accepts either ":all:" to '
         'disable all binary packages, ":none:" to empty the set (notice '
         "the colons), or one or more package names with commas between "
         "them (no colons). Note that some packages are tricky to compile "
-        "and may fail to install when this option is used on them.",
+        "and may fail to install when this option is used on them. "
+        "Additionally, this option forces the use of the legacy 'setup.py install' "
+        "path, unless the 'always-install-via-wheel' feature is enabled.",
     )
 
 
@@ -821,7 +824,10 @@ def _handle_no_use_pep517(option, opt, value, parser):
     'command (use like --install-option="--install-scripts=/usr/local/'
     'bin"). Use multiple --install-option options to pass multiple '
     "options to setup.py install. If you are using an option with a "
-    "directory path, be sure to use absolute path.",
+    "directory path, be sure to use absolute path. "
+    "This option implies '--no-binary :all:'. "
+    "It is ignored by the 'pip install' command when the "
+    "'always-install-via-wheel' feature is enabled.",
 )  # type: Callable[..., Option]
 
 build_options = partial(
@@ -830,7 +836,10 @@ def _handle_no_use_pep517(option, opt, value, parser):
     dest="build_options",
     metavar="options",
     action="append",
-    help="Extra arguments to be supplied to 'setup.py bdist_wheel'.",
+    help="Extra arguments to be supplied to 'setup.py bdist_wheel'. "
+    "This option implies '--no-binary :all:'."
+    "It is ignored by the 'pip install' command unless the "
+    "'always-install-via-wheel' feature is enabled.",
 )  # type: Callable[..., Option]
 
 global_options = partial(
@@ -840,7 +849,8 @@ def _handle_no_use_pep517(option, opt, value, parser):
     action="append",
     metavar="options",
     help="Extra global options to be supplied to the setup.py "
-    "call before the install or bdist_wheel command.",
+    "call before the install or bdist_wheel command. "
+    "This option implies '--no-binary :all:'.",
 )  # type: Callable[..., Option]
 
 no_clean = partial(
@@ -965,7 +975,7 @@ def check_list_path_option(options):
     metavar="feature",
     action="append",
     default=[],
-    choices=["2020-resolver", "fast-deps", "in-tree-build"],
+    choices=["2020-resolver", "fast-deps", "in-tree-build", "always-install-via-wheel"],
     help="Enable new functionality, that may be backward incompatible.",
 )  # type: Callable[..., Option]
 

src/pip/_internal/commands/install.py

@@ -45,10 +45,12 @@
 logger = logging.getLogger(__name__)
 
 
-def get_check_binary_allowed(format_control):
-    # type: (FormatControl) -> BinaryAllowedPredicate
+def get_check_binary_allowed(format_control, features_enabled):
+    # type: (FormatControl, List[str]) -> BinaryAllowedPredicate
     def check_binary_allowed(req):
         # type: (InstallRequirement) -> bool
+        if "always-install-via-wheel" in features_enabled:
+            return True
         canonical_name = canonicalize_name(req.name or "")
         allowed_formats = format_control.get_allowed_formats(canonical_name)
         return "binary" in allowed_formats
@@ -174,6 +176,7 @@ def add_options(self):
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
 
         self.cmd_opts.add_option(cmdoptions.install_options())
+        self.cmd_opts.add_option(cmdoptions.build_options())
         self.cmd_opts.add_option(cmdoptions.global_options())
 
         self.cmd_opts.add_option(
@@ -329,7 +332,7 @@ def run(self, options, args):
             )
 
             check_binary_allowed = get_check_binary_allowed(
-                finder.format_control
+                finder.format_control, options.features_enabled
             )
 
             reqs_to_build = [
@@ -343,8 +346,8 @@ def run(self, options, args):
                 reqs_to_build,
                 wheel_cache=wheel_cache,
                 verify=True,
-                build_options=[],
-                global_options=[],
+                build_options=options.build_options or [],
+                global_options=options.global_options or [],
             )
 
             # If we're using PEP 517, we cannot do a direct install

src/pip/_internal/wheel_builder.py

@@ -75,7 +75,7 @@ def _should_build(
 
     if not check_binary_allowed(req):
         logger.info(
-            "Skipping wheel build for %s, due to binaries "
+            "Using legacy 'setup.py install' for %s, due to binaries "
             "being disabled for it.", req.name,
         )
         return False

tests/functional/test_install.py

@@ -724,6 +724,17 @@ def test_install_global_option(script):
     assert not result.files_created
 
 
+def test_install_global_option_does_not_disable_wheel_building(
+    script, data, with_wheel
+):
+    res = script.pip(
+        'install', '--no-index', '--global-option=-v', '-f', data.find_links,
+        '--use-feature=always-install-via-wheel',
+        'upper', expect_stderr=True)
+    assert "Successfully installed upper-2.0" in str(res), str(res)
+    assert "Building wheel for upper" in str(res), str(res)
+
+
 def test_install_with_hacked_egg_info(script, data):
     """
     test installing a package which defines its own egg_info class
@@ -1439,6 +1450,17 @@ def test_install_no_binary_disables_building_wheels(script, data, with_wheel):
     assert "Running setup.py install for upper" in str(res), str(res)
 
 
+def test_install_no_binary_does_not_disable_building_wheels(
+    script, data, with_wheel
+):
+    res = script.pip(
+        'install', '--no-index', '--no-binary=upper', '-f', data.find_links,
+        '--use-feature=always-install-via-wheel',
+        'upper', expect_stderr=True)
+    assert "Successfully installed upper-2.0" in str(res), str(res)
+    assert "Building wheel for upper" in str(res), str(res)
+
+
 @pytest.mark.network
 def test_install_no_binary_builds_pep_517_wheel(script, data, with_wheel):
     to_install = data.packages.joinpath('pep517_setup_and_pyproject')