fix: use existing executable or unversioned python

Co-Authored-By: Claude <svc-devxp-claude@slack-corp.com>

Author: zimeg

README.md

@@ -57,8 +57,8 @@ Below is an example `/slack.json` file that overrides the default `start`:
 ```json
 {
   "hooks": {
-    "get-hooks": "python3 -m slack_cli_hooks.hooks.get_hooks",
-    "start": "python3 app.py"
+    "get-hooks": "python -m slack_cli_hooks.hooks.get_hooks",
+    "start": "python app.py"
   }
 }
 ```

slack_cli_hooks/hooks/get_hooks.py

@@ -7,7 +7,7 @@
 PROTOCOL: Protocol
 
 # Wrap sys.executable in quotes to prevent execution failures if a white space is present in the absolute python path
-EXEC = f"'{sys.executable}'" or "python3"
+EXEC = f"'{sys.executable}'" if sys.executable else "python"
 
 
 hooks_payload = {

tests/slack_cli_hooks/hooks/test_get_hooks.py

@@ -1,7 +1,22 @@
+import importlib
+import sys
+from unittest.mock import patch
+
+from slack_cli_hooks.hooks import get_hooks
 from slack_cli_hooks.hooks.get_hooks import hooks_payload
 
 
 class TestGetHooks:
+    def test_exec_uses_sys_executable(self):
+        with patch.object(sys, "executable", "/usr/bin/python3"):
+            importlib.reload(get_hooks)
+            assert get_hooks.EXEC == "'/usr/bin/python3'"
+
+    def test_exec_falls_back_to_python_when_sys_executable_is_empty(self):
+        with patch.object(sys, "executable", ""):
+            importlib.reload(get_hooks)
+            assert get_hooks.EXEC == "python"
+
     def test_hooks_payload(self):
         hooks = hooks_payload["hooks"]