Merge pull request #811 from python-cmd2/win_fix

Fixed bug where pipe processes were not being stopped by Ctrl-C on Windows

2 files changed, 15 insertions, 15 deletions

diff --git a/cmd2/cmd2.py b/cmd2/cmd2.py
index 051e6f7c..29bf9529 100644
--- a/cmd2/cmd2.py
+++ b/cmd2/cmd2.py
@@ -56,9 +56,9 @@ from .rl_utils import rl_type, RlType, rl_get_point, rl_set_prompt, vt100_suppor
 
 # Set up readline
 if rl_type == RlType.NONE:  # pragma: no cover
-    rl_warning = "Readline features including tab completion have been disabled since no \n" \
-                 "supported version of readline was found. To resolve this, install \n" \
-                 "pyreadline on Windows or gnureadline on Mac.\n\n"
+    rl_warning = ("Readline features including tab completion have been disabled since no\n"
+                  "supported version of readline was found. To resolve this, install pyreadline\n"
+                  "on Windows or gnureadline on Mac.\n\n")
     sys.stderr.write(ansi.style_warning(rl_warning))
 else:
     from .rl_utils import rl_force_redisplay, readline
@@ -1824,24 +1824,22 @@ class Cmd(cmd.Cmd):
             subproc_stdin = io.open(read_fd, 'r')
             new_stdout = io.open(write_fd, 'w')
 
-            # Set options to not forward signals to the pipe process. If a Ctrl-C event occurs,
-            # our sigint handler will forward it only to the most recent pipe process. This makes
-            # sure pipe processes close in the right order (most recent first).
+            # Create pipe process in a separate group to isolate our signals from it. If a Ctrl-C event occurs,
+            # our sigint handler will forward it only to the most recent pipe process. This makes sure pipe
+            # processes close in the right order (most recent first).
+            kwargs = dict()
             if sys.platform == 'win32':
-                creationflags = subprocess.CREATE_NEW_PROCESS_GROUP
-                start_new_session = False
+                kwargs['creationflags'] = subprocess.CREATE_NEW_PROCESS_GROUP
             else:
-                creationflags = 0
-                start_new_session = True
+                kwargs['start_new_session'] = True
 
             # For any stream that is a StdSim, we will use a pipe so we can capture its output
             proc = subprocess.Popen(statement.pipe_to,
                                     stdin=subproc_stdin,
                                     stdout=subprocess.PIPE if isinstance(self.stdout, utils.StdSim) else self.stdout,
                                     stderr=subprocess.PIPE if isinstance(sys.stderr, utils.StdSim) else sys.stderr,
-                                    creationflags=creationflags,
-                                    start_new_session=start_new_session,
-                                    shell=True)
+                                    shell=True,
+                                    **kwargs)
 
             # Popen was called with shell=True so the user can chain pipe commands and redirect their output
             # like: !ls -l | grep user | wc -l > out.txt. But this makes it difficult to know if the pipe process
diff --git a/cmd2/utils.py b/cmd2/utils.py
index 3155c64a..a1a0d377 100644
--- a/cmd2/utils.py
+++ b/cmd2/utils.py
@@ -517,10 +517,12 @@ class ProcReader(object):
             self._err_thread.start()
 
     def send_sigint(self) -> None:
-        """Send a SIGINT to the process similar to if <Ctrl>+C were pressed."""
+        """Send a SIGINT to the process similar to if <Ctrl>+C were pressed"""
         import signal
         if sys.platform.startswith('win'):
-            self._proc.send_signal(signal.CTRL_C_EVENT)
+            # cmd2 started the Windows process in a new process group. Therefore
+            # a CTRL_C_EVENT can't be sent to it. Send a CTRL_BREAK_EVENT instead.
+            self._proc.send_signal(signal.CTRL_BREAK_EVENT)
         else:
             # Since cmd2 uses shell=True in its Popen calls, we need to send the SIGINT to
             # the whole process group to make sure it propagates further than the shell