[watchmedo] Fix usage of os.setsid() and os.killpg() Unix-only functi…

…ons (#810)

Fixes #809.

Co-authored-by: Mickaël Schoentgen <contact@tiger-222.fr>

.github/workflows/tests.yml

@@ -6,7 +6,7 @@ on:
       - ".github/workflows/tests.yml"
       - "requirements-tests.txt"
       - "setup.*"
-      - "src/*"
+      - "src/**/*"
       - "tests/*.py"
 
 jobs:

changelog.rst

@@ -8,7 +8,8 @@ Changelog
 
 2021-xx-x • `full history <https://github.com/gorakhargosh/watchdog/compare/v2.1.3...master>`__
 
-- Thanks to our beloved contributors: @
+- [watchmedo] Fix usage of ``os.setsid()`` and ``os.killpg()`` Unix-only functions.  (`#809 <https://github.com/gorakhargosh/watchdog/pull/809>`_)
+- Thanks to our beloved contributors: @replabrobin, @BoboTiG
 
 2.1.3
 ~~~~~

src/watchdog/tricks/__init__.py

@@ -170,13 +170,21 @@ def __init__(self, command, patterns=None, ignore_patterns=None,
         self.process = None
 
     def start(self):
-        self.process = subprocess.Popen(self.command, preexec_fn=os.setsid)
+        # windows doesn't have setsid
+        self.process = subprocess.Popen(self.command, preexec_fn=getattr(os, 'setsid', None))
 
     def stop(self):
         if self.process is None:
             return
+
+        def kill_process(stop_signal):
+            if hasattr(os, 'getpgid') and hasattr(os, 'killpg'):
+                os.killpg(os.getpgid(self.process.pid), stop_signal)
+            else:
+                os.kill(self.process.pid, self.stop_signal)
+
         try:
-            os.killpg(os.getpgid(self.process.pid), self.stop_signal)
+            kill_process(self.stop_signal)
         except OSError:
             # Process is already gone
             pass
@@ -188,7 +196,7 @@ def stop(self):
                 time.sleep(0.25)
             else:
                 try:
-                    os.killpg(os.getpgid(self.process.pid), 9)
+                    kill_process(9)
                 except OSError:
                     # Process is already gone
                     pass

tests/test_watchmedo.py

@@ -48,3 +48,26 @@ def test_load_config_invalid(tmpdir):
         watchmedo.load_config(yaml_file)
 
     assert not os.path.exists(critical_dir)
+
+
+def make_dummy_script(tmpdir, n=10):
+    script = os.path.join(tmpdir, 'auto-test-%d.py' % n)
+    with open(script, 'w') as f:
+        f.write('import time\nfor i in range(%d):\n\tprint("+++++ %%d" %% i, flush=True)\n\ttime.sleep(1)\n' % n)
+    return script
+
+
+def test_kill_auto_restart(tmpdir, capfd):
+    from watchdog.tricks import AutoRestartTrick
+    import sys
+    import time
+    script = make_dummy_script(tmpdir)
+    a = AutoRestartTrick([sys.executable, script])
+    a.start()
+    time.sleep(5)
+    a.stop()
+    cap = capfd.readouterr()
+    assert '+++++ 0' in cap.out
+    assert '+++++ 9' not in cap.out     # we killed the subprocess before the end
+    # in windows we seem to lose the subprocess stderr
+    # assert 'KeyboardInterrupt' in cap.err