Restore SSHArgumentParser wrapper

I think this is the best approach after all to catch errors from the
options parser quietly.

1 files changed, 18 insertions, 2 deletions

diff --git a/ssh_negotiate_term.py3 b/ssh_negotiate_term.py3
index 31cb869..3c99613 100644
--- a/ssh_negotiate_term.py3
+++ b/ssh_negotiate_term.py3
@@ -13,6 +13,22 @@ import re
 import sys
 
 
+class SSHArgumentParserError(Exception):
+    """
+    Exception for SSHArgumentParser to throw on error.
+    """
+
+
+class SSHArgumentParser(argparse.ArgumentParser):
+    """
+    Subclass argparse.ArgumentParser just so that errors raise exceptions
+    rather than exiting.
+    """
+
+    def error(self, message):
+        raise SSHArgumentParserError(message)
+
+
 class SSHNegotiateTerm():
     """
     Using a class, to encapsulate a fair bit of system state that gets injected
@@ -77,7 +93,7 @@ class SSHNegotiateTerm():
             return False
 
         # Parse the SSH command line to try and get the hostname
-        parser = argparse.ArgumentParser()
+        parser = SSHArgumentParser()
         for letter in self.SSH_OPTIONS_SWITCHES:
             parser.add_argument('-' + letter, action='store_true')
         for letter in self.SSH_OPTIONS_ARGUMENTS:
@@ -88,7 +104,7 @@ class SSHNegotiateTerm():
         try:
             args = parser.parse_args(self.argv[1:])
             hostname = args.hostname
-        except SystemExit:
+        except SSHArgumentParserError:
             return False
 
         # If the hostname looks like an IPv4 or IPv6 address, we'll downgrade