Tool to implement robust cleanups even on process crash

kitty_tests/atexit.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+# License: GPLv3 Copyright: 2025, Kovid Goyal <kovid at kovidgoyal.net>
+
+
+import os
+import select
+import shutil
+import signal
+import subprocess
+import tempfile
+
+from kitty.constants import kitten_exe, kitty_exe
+
+from . import BaseTest
+
+
+class Atexit(BaseTest):
+
+    def setUp(self):
+        self.tdir = tempfile.mkdtemp()
+
+    def tearDown(self):
+        shutil.rmtree(self.tdir)
+
+    def test_atexit(self):
+
+        def r(action='close'):
+            p = subprocess.Popen([kitty_exe(), '+runpy', f'''\
+import subprocess
+p = subprocess.Popen(['{kitten_exe()}', '__atexit__'])
+print(p.pid, flush=True)
+raise SystemExit(p.wait())
+'''], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+            readers = [p.stdout.fileno()]
+            def read():
+                r, _, _ = select.select(readers, [], [], 10)
+                if not r:
+                    raise TimeoutError('Timed out waiting for read from child')
+                return p.stdout.readline().rstrip().decode()
+            atexit_pid = int(read())
+            for i in range(2):
+                with open(os.path.join(self.tdir, str(i)), 'w') as f:
+                    p.stdin.write(f'unlink {f.name}\n'.encode())
+                    p.stdin.flush()
+                select.select(readers, [], [], 10)
+                self.ae(read(), str(i+1))
+            self.assertTrue(os.listdir(self.tdir))
+
+            # Ensure child is ignoring signals
+            os.kill(atexit_pid, signal.SIGINT)
+            os.kill(atexit_pid, signal.SIGTERM)
+            if action == 'close':
+                p.stdin.close()
+            elif action == 'terminate':
+                p.terminate()
+            else:
+                p.kill()
+            p.wait(10)
+            if action != 'close':
+                p.stdin.close()
+            select.select(readers, [], [], 10)
+            self.assertFalse(read())
+            p.stdout.close()
+            self.assertFalse(os.listdir(self.tdir))
+            try:
+                os.waitpid(atexit_pid, 0)
+            except ChildProcessError:
+                pass
+
+        r('close')
+        r('terminate')
+        r('kill')