Error if the --python option is specified after the subcommand name

news/12067.bugfix.rst

@@ -0,0 +1 @@
+Fail with an error if the ``--python`` option is specified after the subcommand name.

src/pip/_internal/cli/base_command.py

@@ -131,6 +131,17 @@ def _main(self, args: List[str]) -> int:
                 ", ".join(sorted(always_enabled_features)),
             )
 
+        # Make sure that the --python argument isn't specified after the
+        # subcommand. We can tell, because if --python was specified,
+        # we should only reach this point if we're running in the created
+        # subprocess, which has the _PIP_RUNNING_IN_SUBPROCESS environment
+        # variable set.
+        if options.python and "_PIP_RUNNING_IN_SUBPROCESS" not in os.environ:
+            logger.critical(
+                "The --python option must be placed before the pip subcommand name"
+            )
+            sys.exit(ERROR)
+
         # TODO: Try to get these passing down from the command?
         #       without resorting to os.environ to hold these.
         #       This also affects isolated builds and it should.

tests/functional/test_install.py

@@ -1157,7 +1157,7 @@ def test_install_nonlocal_compatible_wheel(
         "--find-links",
         data.find_links,
         "--only-binary=:all:",
-        "--python",
+        "--python-version",
         "3",
         "--platform",
         "fakeplat",
@@ -1177,7 +1177,7 @@ def test_install_nonlocal_compatible_wheel(
         "--find-links",
         data.find_links,
         "--only-binary=:all:",
-        "--python",
+        "--python-version",
         "3",
         "--platform",
         "fakeplat",

tests/functional/test_python_option.py

@@ -39,3 +39,15 @@ def test_python_interpreter(
     script.pip("--python", env_path, "uninstall", "simplewheel", "--yes")
     result = script.pip("--python", env_path, "list", "--format=json")
     assert json.loads(result.stdout) == before
+
+
+def test_error_python_option_wrong_location(
+    script: PipTestEnvironment,
+    tmpdir: Path,
+    shared_data: TestData,
+) -> None:
+    env_path = os.fspath(tmpdir / "venv")
+    env = EnvBuilder(with_pip=False)
+    env.create(env_path)
+
+    script.pip("list", "--python", env_path, "--format=json", expect_error=True)