fix: make click a truly optional dependency of the s7 command

CHANGES.md

@@ -13,6 +13,8 @@ Unreleased
 
 ### Bug fixes
 
+* The `s7` command now prints an install hint and exits when the optional `click` dependency is missing, instead of
+  failing with an `ImportError` traceback, so `click` stays an optional `cli` extra (#954).
 * `get_string` and `get_wstring` now raise `ValueError` when the buffer is shorter than the declared current length,
   instead of silently returning a truncated value (#945).
 * USERDATA responses whose last-data-unit byte is neither `0x00` nor `0x01` are rejected with `S7ProtocolError`

pyproject.toml

@@ -47,7 +47,7 @@ include = ["snap7*", "s7*"]
 
 [project.scripts]
 snap7-server = "snap7.server:mainloop"
-s7 = "snap7.cli:main"
+s7 = "snap7._console:main"
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]

snap7/_console.py

@@ -0,0 +1,19 @@
+"""
+Console entry point for the ``s7`` command.
+
+The CLI depends on the optional ``click`` package (``pip install python-snap7[cli]``). This wrapper checks for it before
+importing :mod:`snap7.cli`, so a plain install prints an install hint instead of an ``ImportError`` traceback.
+"""
+
+import importlib.util
+import sys
+
+
+def main() -> None:
+    if importlib.util.find_spec("click") is None:
+        print("The s7 command requires the CLI dependencies. Install them with: pip install python-snap7[cli]", file=sys.stderr)
+        sys.exit(1)
+
+    from snap7.cli import main as cli_main
+
+    cli_main()

tests/test_console.py

@@ -0,0 +1,35 @@
+"""Tests for the s7 console entry point wrapper."""
+
+import importlib.util
+from typing import Any
+from unittest.mock import patch
+
+import pytest
+
+from snap7 import _console
+
+
+@pytest.mark.client
+def test_missing_click_prints_install_hint(capsys: pytest.CaptureFixture[str]) -> None:
+    real_find_spec = importlib.util.find_spec
+
+    def find_spec(name: str, *args: Any, **kwargs: Any) -> Any:
+        if name == "click":
+            return None
+        return real_find_spec(name, *args, **kwargs)
+
+    with patch.object(importlib.util, "find_spec", find_spec):
+        with pytest.raises(SystemExit) as exc_info:
+            _console.main()
+
+    assert exc_info.value.code == 1
+    assert "pip install python-snap7[cli]" in capsys.readouterr().err
+
+
+@pytest.mark.client
+def test_runs_cli_when_click_installed() -> None:
+    pytest.importorskip("click")
+    with patch("sys.argv", ["s7", "--help"]):
+        with pytest.raises(SystemExit) as exc_info:
+            _console.main()
+    assert exc_info.value.code == 0