Merge branch 'master' into quoted_completion

5 files changed, 51 insertions, 6 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7359ea08..0082a067 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
     * Fixed a bug in tab-completion of command names within sub-menus
     * Fixed a bug when using persistent readline history in Python 2.7
     * Fixed a bug where the ``AddSubmenu`` decorator didn't work with a default value for ``shared_attributes``
+    * Added a check to ``ppaged()`` to only use a pager when running in a real fully functional terminal
 * Enhancements
     * Added [quit_on_sigint](http://cmd2.readthedocs.io/en/latest/settingchanges.html#quit-on-sigint) attribute to enable canceling current line instead of quitting when Ctrl+C is typed
     * Added possibility of having readline history preservation in a SubMenu
@@ -11,6 +12,7 @@
     * Added command aliasing with ``alias`` and ``unalias`` commands
     * Added the ability to load an initialization script at startup
         * See [alias_startup.py](https://github.com/python-cmd2/cmd2/blob/master/examples/alias_startup.py) for an example
+    * Added a default SIGINT handler which terminates any open pipe subprocesses and re-raises a KeyboardInterrupt
     
 ## 0.8.1 (March 9, 2018)
 
diff --git a/cmd2.py b/cmd2.py
index a8171603..6bbfc94e 100755
--- a/cmd2.py
+++ b/cmd2.py
@@ -37,6 +37,7 @@ import platform
 import re
 import shlex
 import shutil
+import signal
 import six
 import sys
 import tempfile
@@ -1243,7 +1244,7 @@ class Cmd(cmd.Cmd):
     allow_cli_args = True       # Should arguments passed on the command-line be processed as commands?
     allow_redirection = True    # Should output redirection and pipes be allowed
     default_to_shell = False    # Attempt to run unrecognized commands as shell commands
-    quit_on_sigint = True       # Quit the loop on interrupt instead of just resetting prompt
+    quit_on_sigint = False      # Quit the loop on interrupt instead of just resetting prompt
     reserved_words = []
 
     # Attributes which ARE dynamically settable at runtime
@@ -1453,7 +1454,8 @@ class Cmd(cmd.Cmd):
     def ppaged(self, msg, end='\n'):
         """Print output using a pager if it would go off screen and stdout isn't currently being redirected.
 
-        Never uses a pager inside of a script (Python or text) or when output is being redirected or piped.
+        Never uses a pager inside of a script (Python or text) or when output is being redirected or piped or when
+        stdout or stdin are not a fully functional terminal.
 
         :param msg: str - message to print to current stdout - anything convertible to a str with '{}'.format() is OK
         :param end: str - string appended after the end of the message if not already present, default a newline
@@ -1464,8 +1466,18 @@ class Cmd(cmd.Cmd):
                 if not msg_str.endswith(end):
                     msg_str += end
 
+                # Attempt to detect if we are not running within a fully functional terminal.
+                # Don't try to use the pager when being run by a continuous integration system like Jenkins + pexpect.
+                functional_terminal = False
+
+                if self.stdin.isatty() and self.stdout.isatty():
+                    if sys.platform.startswith('win') or os.environ.get('TERM') is not None:
+                        functional_terminal = True
+
                 # Don't attempt to use a pager that can block if redirecting or running a script (either text or Python)
-                if not self.redirecting and not self._in_py and not self._script_dir:
+                # Also only attempt to use a pager if actually running in a real fully functional terminal
+                if functional_terminal and not self.redirecting and not self._in_py and not self._script_dir:
+
                     if sys.platform.startswith('win'):
                         pager_cmd = 'more'
                     else:
@@ -1842,6 +1854,31 @@ class Cmd(cmd.Cmd):
         completions.sort()
         return completions
 
+    # noinspection PyUnusedLocal
+    def sigint_handler(self, signum, frame):
+        """Signal handler for SIGINTs which typically come from Ctrl-C events.
+
+        If you need custom SIGINT behavior, then override this function.
+
+        :param signum: int - signal number
+        :param frame
+        """
+
+        # Save copy of pipe_proc since it could theoretically change while this is running
+        pipe_proc = self.pipe_proc
+
+        if pipe_proc is not None:
+            pipe_proc.terminate()
+
+        # Re-raise a KeyboardInterrupt so other parts of the code can catch it
+        raise KeyboardInterrupt("Got a keyboard interrupt")
+
+    def preloop(self):
+        """"Hook method executed once when the cmdloop() method is called."""
+
+        # Register a default SIGINT signal handler for Ctrl+C
+        signal.signal(signal.SIGINT, self.sigint_handler)
+
     def precmd(self, statement):
         """Hook method executed just before the command is processed by ``onecmd()`` and after adding it to the history.
 
diff --git a/examples/paged_output.py b/examples/paged_output.py
index 171c1b3e..9005a4da 100755
--- a/examples/paged_output.py
+++ b/examples/paged_output.py
@@ -17,6 +17,10 @@ class PagedOutput(cmd2.Cmd):
     @with_argument_list
     def do_page_file(self, args):
         """Read in a text file and display its output in a pager."""
+        if not args:
+            self.perror('page_file requires a path to a file as an argument', traceback_war=False)
+            return
+
         with open(args[0], 'r') as f:
             text = f.read()
         self.ppaged(text)
diff --git a/examples/subcommands.py b/examples/subcommands.py
index fa99f6b4..2a7e0afa 100755
--- a/examples/subcommands.py
+++ b/examples/subcommands.py
@@ -63,11 +63,11 @@ class SubcommandsExample(cmd2.Cmd):
     @with_argparser(base_parser)
     def do_base(self, args):
         """Base command help"""
-        try:
+        if args.func is not None:
             # Call whatever subcommand function was selected
             args.func(self, args)
-        except AttributeError:
-            # No subcommand was provided, so as called
+        else:
+            # No subcommand was provided, so call help
             self.do_help('base')
 
     # functools.partialmethod was added in Python 3.4
diff --git a/tests/test_cmd2.py b/tests/test_cmd2.py
index d69bf343..20d477ba 100644
--- a/tests/test_cmd2.py
+++ b/tests/test_cmd2.py
@@ -915,6 +915,8 @@ def say_app():
     return app
 
 def test_interrupt_quit(say_app):
+    say_app.quit_on_sigint = True
+
     # Mock out the input call so we don't actually wait for a user's response on stdin
     m = mock.MagicMock(name='input')
     m.side_effect = ['say hello', KeyboardInterrupt(), 'say goodbye', 'eof']