Shorten Escape key delay in OCI dialog menus

.github/workflows/test-oci-registries.yml

@@ -38,5 +38,6 @@ jobs:
         run: |
           python3 -m unittest discover -s oci/tests -p test_modify_latency.py -v
           python3 -m unittest discover -s oci/tests -p test_menu_performance.py -v
+          python3 -m unittest discover -s oci/tests -p test_dialog_escape.py -v
           python3 -m unittest discover -s oci/tests -p test_work_backup.py -v
           python3 -m unittest discover -s oci/tests -p test_recreation.py -v

oci/src/proxmenux_oci/ui.py

@@ -221,6 +221,10 @@ class DialogUI:
 
     def _run(self, widget: list[str], title: str | None = None) -> subprocess.CompletedProcess[str]:
         environment = os.environ.copy()
+        # ncurses otherwise waits a full second to distinguish Escape from
+        # the prefix of a cursor/function key. Keep a short sequence window,
+        # while respecting an explicit terminal-specific setting.
+        environment.setdefault("ESCDELAY", "150")
         if environment.get("TERM", "").casefold() in {"", "dumb", "unknown"}:
             environment["TERM"] = "xterm-256color"
         # dialog draws on the terminal and writes the selection to stderr.

oci/tests/test_dialog_escape.py

@@ -0,0 +1,34 @@
+"""Escape delay is scoped to dialog and preserves terminal-specific overrides."""
+import os
+from pathlib import Path
+import subprocess
+import sys
+import unittest
+from unittest.mock import patch
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / 'src'))
+from proxmenux_oci.ui import DialogUI, UserCancelled
+
+
+class DialogEscapeTests(unittest.TestCase):
+    def test_escape_uses_short_delay_without_changing_parent_environment(self):
+        with patch.dict(os.environ, {'TERM': 'xterm'}, clear=True), \
+                patch('proxmenux_oci.ui.subprocess.run', return_value=subprocess.CompletedProcess([], 255, stderr='')) as run:
+            self.assertIsNone(DialogUI().choose('Menu', [('1', 'First')]))
+            self.assertEqual(run.call_args.kwargs['env']['ESCDELAY'], '150')
+            self.assertNotIn('ESCDELAY', os.environ)
+
+    def test_explicit_delay_is_preserved(self):
+        with patch.dict(os.environ, {'ESCDELAY': '900'}), \
+                patch('proxmenux_oci.ui.subprocess.run', return_value=subprocess.CompletedProcess([], 0, stderr='1')) as run:
+            self.assertEqual(DialogUI().choose('Menu', [('1', 'First')]), '1')
+            self.assertEqual(run.call_args.kwargs['env']['ESCDELAY'], '900')
+
+    def test_escape_in_search_input_keeps_cancellation_behavior(self):
+        with patch('proxmenux_oci.ui.subprocess.run', return_value=subprocess.CompletedProcess([], 255, stderr='')):
+            with self.assertRaises(UserCancelled):
+                DialogUI().ask('Search')
+
+
+if __name__ == '__main__':
+    unittest.main()