Include Python runtime in CLI version output

Author: ac1982

README.md

@@ -76,6 +76,10 @@ Only on Alpine Linux the package is named differently. You can install it there
 apk add py3-lsp-server
 ```
 
+Run `pylsp --version` (or `pylsp -V`) to see both the server version and the
+Python version running it. This reports the server runtime, which may differ
+from the interpreter or target Python version configured for individual plugins.
+
 ### 3rd Party Plugins
 
 Installing these plugins will add extra functionality to the language server:

pylsp/__main__.py

@@ -4,6 +4,7 @@
 import argparse
 import logging
 import logging.config
+import platform
 import sys
 import time
 
@@ -63,7 +64,10 @@ def add_arguments(parser) -> None:
     )
 
     parser.add_argument(
-        "-V", "--version", action="version", version="%(prog)s v" + __version__
+        "-V",
+        "--version",
+        action="version",
+        version=f"%(prog)s v{__version__} (Python {platform.python_version()})",
     )
 
 

test/test_main.py

@@ -0,0 +1,23 @@
+# Copyright 2021- Python Language Server Contributors.
+
+import platform
+import subprocess
+import sys
+
+import pytest
+
+from pylsp._version import __version__
+
+
+@pytest.mark.parametrize("flag", ["--version", "-V"])
+def test_version_includes_python_runtime(flag):
+    result = subprocess.run(
+        [sys.executable, "-m", "pylsp", flag],
+        capture_output=True,
+        text=True,
+        check=True,
+        timeout=10,
+    )
+    assert f"v{__version__}" in result.stdout
+    assert f"Python {platform.python_version()}" in result.stdout
+    assert result.stderr == ""