Fixed issue where persistent history file was not saved upon SIGTERM …

…and SIGHUP signals.

cmd2/cmd2.py

@@ -780,7 +780,7 @@ def unregister_command_set(self, cmdset: CommandSet) -> None:
 
             methods = inspect.getmembers(
                 cmdset,
-                predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type]
+                predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type, var-annotated]
                 and hasattr(meth, '__name__')
                 and meth.__name__.startswith(COMMAND_FUNC_PREFIX),
             )
@@ -811,7 +811,7 @@ def unregister_command_set(self, cmdset: CommandSet) -> None:
     def _check_uninstallable(self, cmdset: CommandSet) -> None:
         methods = inspect.getmembers(
             cmdset,
-            predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type]
+            predicate=lambda meth: isinstance(meth, Callable)  # type: ignore[arg-type, var-annotated]
             and hasattr(meth, '__name__')
             and meth.__name__.startswith(COMMAND_FUNC_PREFIX),
         )
@@ -2418,7 +2418,7 @@ def get_help_topics(self) -> List[str]:
     def sigint_handler(self, signum: int, _: FrameType) -> None:
         """Signal handler for SIGINTs which typically come from Ctrl-C events.
 
-        If you need custom SIGINT behavior, then override this function.
+        If you need custom SIGINT behavior, then override this method.
 
         :param signum: signal number
         :param _: required param for signal handlers
@@ -2437,6 +2437,30 @@ def sigint_handler(self, signum: int, _: FrameType) -> None:
             if raise_interrupt:
                 self._raise_keyboard_interrupt()
 
+    def sigterm_handler(self, signum: int, _: FrameType) -> None:
+        """
+        Signal handler for SIGTERMs which are sent to politely ask this app to terminate.
+
+        If you need custom SIGTERM behavior, then override this method.
+
+        :param signum: signal number
+        :param _: required param for signal handlers
+        """
+        # Gracefully exit so the persistent history file will be written.
+        sys.exit(self.exit_code)
+
+    def sighup_handler(self, signum: int, _: FrameType) -> None:
+        """
+        Signal handler for SIGHUPs which are sent when the terminal is closed.
+
+        If you need custom SIGHUP behavior, then override this method.
+
+        :param signum: signal number
+        :param _: required param for signal handlers
+        """
+        # Gracefully exit so the persistent history file will be written.
+        sys.exit(self.exit_code)
+
     def _raise_keyboard_interrupt(self) -> None:
         """Helper function to raise a KeyboardInterrupt"""
         raise KeyboardInterrupt("Got a keyboard interrupt")
@@ -5447,6 +5471,12 @@ def cmdloop(self, intro: Optional[str] = None) -> int:  # type: ignore[override]
         original_sigint_handler = signal.getsignal(signal.SIGINT)
         signal.signal(signal.SIGINT, self.sigint_handler)  # type: ignore
 
+        original_sigterm_handler = signal.getsignal(signal.SIGTERM)
+        signal.signal(signal.SIGTERM, self.sigterm_handler)  # type: ignore
+
+        original_sighup_handler = signal.getsignal(signal.SIGHUP)
+        signal.signal(signal.SIGHUP, self.sighup_handler)  # type: ignore
+
         # Grab terminal lock before the command line prompt has been drawn by readline
         self.terminal_lock.acquire()
 
@@ -5479,8 +5509,10 @@ def cmdloop(self, intro: Optional[str] = None) -> int:  # type: ignore[override]
         # This will also zero the lock count in case cmdloop() is called again
         self.terminal_lock.release()
 
-        # Restore the original signal handler
+        # Restore the original signal handlers
         signal.signal(signal.SIGINT, original_sigint_handler)
+        signal.signal(signal.SIGTERM, original_sigterm_handler)
+        signal.signal(signal.SIGHUP, original_sighup_handler)
 
         return self.exit_code