inspect: add experimental status warning

src/pip/_internal/commands/inspect.py

@@ -1,3 +1,4 @@
+import logging
 from optparse import Values
 from typing import Any, Dict, List
 
@@ -12,6 +13,8 @@ from pip._internal.metadata import BaseDistribution, get_environment
 from pip._internal.utils.compat import stdlib_pkgs
 from pip._internal.utils.urls import path_to_url
 
+logger = logging.getLogger(__name__)
+
 
 class InspectCommand(Command):
     """
@@ -43,6 +46,11 @@ class InspectCommand(Command):
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options: Values, args: List[str]) -> int:
+        logger.warning(
+            "pip inspect is currently an experimental command. "
+            "The output format may change in a future release without prior warning."
+        )
+
         cmdoptions.check_list_path_option(options)
         dists = get_environment(options.path).iter_installed_distributions(
             local_only=options.local,

tests/functional/test_inspect.py

@@ -28,7 +28,7 @@ def test_inspect_basic(simple_script: PipTestEnvironment) -> None:
     """
     Test default behavior of inspect command.
     """
-    result = simple_script.pip("inspect")
+    result = simple_script.pip("inspect", allow_stderr_warning=True)
     report = json.loads(result.stdout)
     installed = report["installed"]
     assert len(installed) == 4