[ipython] Do some sanity checks before starting the console

* Even if IPython is not installed, restore sys.stdout (Python 3 only)
* Prevent starting the console without a tty (ie. prevent starting the
console when the shell is detached)
* Prevent starting the console when running as a deamon

ipython.py

@@ -19,13 +19,13 @@
     # on import as well
     sys.stdout = sys.__stdout__
     sys.stderr = sys.__stderr__
-
-from IPython.frontend.terminal.embed import InteractiveShellEmbed
-
-if sys.version_info.major >= 3:
-    # Restore stderr/stdout wrappers
-    sys.stdout = old_stdout
-    sys.stderr = old_stderr
+try:
+    from IPython.frontend.terminal.embed import InteractiveShellEmbed
+finally:
+    if sys.version_info.major >= 3:
+        # Restore stderr/stdout wrappers
+        sys.stdout = old_stdout
+        sys.stderr = old_stderr
 
 console = None
 
@@ -42,6 +42,12 @@ def interactive_shell(bot, trigger):
     if 'iconsole_running' in bot.memory and bot.memory['iconsole_running']:
         bot.say('Console already running')
         return
+    if not sys.__stdout__.isatty():
+        bot.say('A tty is required to start the console')
+        return
+    if bot.config._is_deamonized:
+        bot.say('Can\'t start console when running as a deamon')
+        return
 
     # Backup stderr/stdout wrappers
     old_stdout = sys.stdout