Not handling SIGHUP and SIGTERM on Windows.

Author: kmvanbrunt

CHANGELOG.md

@@ -2,7 +2,7 @@
 * Breaking Change
   * `cmd2` 2.5 supports Python 3.7+ (removed support for Python 3.6)
 * Bug Fixes
-  * Fixed issue where persistent history file was not saved upon SIGTERM and SIGHUP signals.
+  * Fixed issue where persistent history file was not saved upon SIGHUP and SIGTERM signals.
 * Enhancements
   * Removed dependency on `attrs` and replaced with [dataclasses](https://docs.python.org/3/library/dataclasses.html)
   * add `allow_clipboard` initialization parameter and attribute to disable ability to

cmd2/argparse_custom.py

@@ -352,8 +352,7 @@ class ChoicesProviderFuncBase(Protocol):
     Function that returns a list of choices in support of tab completion
     """
 
-    def __call__(self) -> List[str]:
-        ...  # pragma: no cover
+    def __call__(self) -> List[str]: ...  # pragma: no cover
 
 
 @runtime_checkable
@@ -362,8 +361,7 @@ class ChoicesProviderFuncWithTokens(Protocol):
     Function that returns a list of choices in support of tab completion and accepts a dictionary of prior arguments.
     """
 
-    def __call__(self, *, arg_tokens: Dict[str, List[str]] = {}) -> List[str]:
-        ...  # pragma: no cover
+    def __call__(self, *, arg_tokens: Dict[str, List[str]] = {}) -> List[str]: ...  # pragma: no cover
 
 
 ChoicesProviderFunc = Union[ChoicesProviderFuncBase, ChoicesProviderFuncWithTokens]
@@ -381,8 +379,7 @@ def __call__(
         line: str,
         begidx: int,
         endidx: int,
-    ) -> List[str]:
-        ...  # pragma: no cover
+    ) -> List[str]: ...  # pragma: no cover
 
 
 @runtime_checkable
@@ -400,8 +397,7 @@ def __call__(
         endidx: int,
         *,
         arg_tokens: Dict[str, List[str]] = {},
-    ) -> List[str]:
-        ...  # pragma: no cover
+    ) -> List[str]: ...  # pragma: no cover
 
 
 CompleterFunc = Union[CompleterFuncBase, CompleterFuncWithTokens]

cmd2/cmd2.py

@@ -854,7 +854,7 @@ def _register_subcommands(self, cmdset: Union[CommandSet, 'Cmd']) -> None:
         )
 
         # iterate through all matching methods
-        for method_name, method in methods:
+        for _, method in methods:
             subcommand_name: str = getattr(method, constants.SUBCMD_ATTR_NAME)
             full_command_name: str = getattr(method, constants.SUBCMD_ATTR_COMMAND)
             subcmd_parser_builder = getattr(method, constants.CMD_ATTR_ARGPARSER)
@@ -963,7 +963,7 @@ def _unregister_subcommands(self, cmdset: Union[CommandSet, 'Cmd']) -> None:
         )
 
         # iterate through all matching methods
-        for method_name, method in methods:
+        for _, method in methods:
             subcommand_name = getattr(method, constants.SUBCMD_ATTR_NAME)
             command_name = getattr(method, constants.SUBCMD_ATTR_COMMAND)
 
@@ -2430,29 +2430,22 @@ def sigint_handler(self, signum: int, _: FrameType) -> None:
             if raise_interrupt:
                 self._raise_keyboard_interrupt()
 
-    def sigterm_handler(self, signum: int, _: FrameType) -> None:  # pragma: no cover
+    def termination_signal_handler(self, signum: int, _: FrameType) -> None:
         """
-        Signal handler for SIGTERMs which are sent to politely ask this app to terminate.
+        Signal handler for SIGHUP and SIGTERM. Only runs on Linux and Mac.
 
-        If you need custom SIGTERM behavior, then override this method.
+        SIGHUP - received when terminal window is closed.
+        SIGTERM - received when this process politely asked to terminate.
 
-        :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:  # pragma: no cover
-        """
-        Signal handler for SIGHUPs which are sent when the terminal is closed.
-
-        If you need custom SIGHUP behavior, then override this method.
+        The basic purpose of this method is to call sys.exit() so our atexit handler will run
+        and save the persistent history file. If you need more complex behavior like killing
+        threads and performing cleanup, 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)
+        # POSIX systems add 128 to signal numbers for the exit code
+        sys.exit(128 + signum)
 
     def _raise_keyboard_interrupt(self) -> None:
         """Helper function to raise a KeyboardInterrupt"""
@@ -5458,17 +5451,18 @@ def cmdloop(self, intro: Optional[str] = None) -> int:  # type: ignore[override]
         if not threading.current_thread() is threading.main_thread():
             raise RuntimeError("cmdloop must be run in the main thread")
 
-        # Register a SIGINT signal handler for Ctrl+C
+        # Register signal handlers
         import signal
 
         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
+        if not sys.platform.startswith('win'):
+            original_sighup_handler = signal.getsignal(signal.SIGHUP)
+            signal.signal(signal.SIGHUP, self.termination_signal_handler)  # type: ignore
 
-        original_sighup_handler = signal.getsignal(signal.SIGHUP)
-        signal.signal(signal.SIGHUP, self.sighup_handler)  # type: ignore
+            original_sigterm_handler = signal.getsignal(signal.SIGTERM)
+            signal.signal(signal.SIGTERM, self.termination_signal_handler)  # type: ignore
 
         # Grab terminal lock before the command line prompt has been drawn by readline
         self.terminal_lock.acquire()
@@ -5502,10 +5496,12 @@ 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 handlers
+        # Restore original signal handlers
         signal.signal(signal.SIGINT, original_sigint_handler)
-        signal.signal(signal.SIGTERM, original_sigterm_handler)
-        signal.signal(signal.SIGHUP, original_sighup_handler)
+
+        if not sys.platform.startswith('win'):
+            signal.signal(signal.SIGHUP, original_sighup_handler)
+            signal.signal(signal.SIGTERM, original_sigterm_handler)
 
         return self.exit_code
 

cmd2/decorators.py

@@ -266,8 +266,7 @@ def with_argparser(
     ns_provider: Optional[Callable[..., argparse.Namespace]] = None,
     preserve_quotes: bool = False,
     with_unknown_args: bool = False,
-) -> Callable[[ArgparseCommandFunc[CommandParent]], RawCommandFuncOptionalBoolReturn[CommandParent]]:
-    ...  # pragma: no cover
+) -> Callable[[ArgparseCommandFunc[CommandParent]], RawCommandFuncOptionalBoolReturn[CommandParent]]: ...  # pragma: no cover
 
 
 @overload
@@ -277,8 +276,7 @@ def with_argparser(
     ns_provider: Optional[Callable[..., argparse.Namespace]] = None,
     preserve_quotes: bool = False,
     with_unknown_args: bool = False,
-) -> Callable[[ArgparseCommandFunc[CommandParent]], RawCommandFuncOptionalBoolReturn[CommandParent]]:
-    ...  # pragma: no cover
+) -> Callable[[ArgparseCommandFunc[CommandParent]], RawCommandFuncOptionalBoolReturn[CommandParent]]: ...  # pragma: no cover
 
 
 def with_argparser(
@@ -418,8 +416,7 @@ def as_subcommand_to(
     *,
     help: Optional[str] = None,
     aliases: Optional[List[str]] = None,
-) -> Callable[[ArgparseCommandFunc[CommandParent]], ArgparseCommandFunc[CommandParent]]:
-    ...  # pragma: no cover
+) -> Callable[[ArgparseCommandFunc[CommandParent]], ArgparseCommandFunc[CommandParent]]: ...  # pragma: no cover
 
 
 @overload
@@ -430,8 +427,7 @@ def as_subcommand_to(
     *,
     help: Optional[str] = None,
     aliases: Optional[List[str]] = None,
-) -> Callable[[ArgparseCommandFunc[CommandParent]], ArgparseCommandFunc[CommandParent]]:
-    ...  # pragma: no cover
+) -> Callable[[ArgparseCommandFunc[CommandParent]], ArgparseCommandFunc[CommandParent]]: ...  # pragma: no cover
 
 
 def as_subcommand_to(

cmd2/history.py

@@ -154,12 +154,10 @@ def _zero_based_index(self, onebased: Union[int, str]) -> int:
         return result
 
     @overload
-    def append(self, new: HistoryItem) -> None:
-        ...  # pragma: no cover
+    def append(self, new: HistoryItem) -> None: ...  # pragma: no cover
 
     @overload
-    def append(self, new: Statement) -> None:
-        ...  # pragma: no cover
+    def append(self, new: Statement) -> None: ...  # pragma: no cover
 
     def append(self, new: Union[Statement, HistoryItem]) -> None:
         """Append a new statement to the end of the History list.

tests/test_cmd2.py

@@ -1038,6 +1038,17 @@ def test_raise_keyboard_interrupt(base_app):
     assert 'Got a keyboard interrupt' in str(excinfo.value)
 
 
+@pytest.mark.skipif(sys.platform.startswith('win'), reason="SIGTERM only handeled on Linux/Mac")
+def test_termination_signal_handler(base_app):
+    with pytest.raises(SystemExit) as excinfo:
+        base_app.termination_signal_handler(signal.SIGHUP, 1)
+    assert excinfo.value.code == signal.SIGHUP + 128
+
+    with pytest.raises(SystemExit) as excinfo:
+        base_app.termination_signal_handler(signal.SIGTERM, 1)
+    assert excinfo.value.code == signal.SIGTERM + 128
+
+
 class HookFailureApp(cmd2.Cmd):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)