cws-status: Exit with code `EX_USAGE` on argument parse errorv0.0.1

I tried catching the `argparse.ArgumentError` as described here, but
that didn't seem to work:
https://docs.python.org/3.9/library/argparse.html#exit-on-error

When I wrapped `args = argparser.parse_args()` in a `try` block, it
raised a `SystemExit` exception instead of `argparse.ArgumentError`.

Take inspiration from some of the suggestions in this Stack Overflow
answer:
https://stackoverflow.com/questions/5943249/python-argparse-and-controlling-overriding-the-exit-status-code

Since we just want to change the exit code, call
`argparse.ArgumentParser`'s `error()` method and exit with the error
code we want.

1 files changed, 10 insertions, 1 deletions

diff --git a/cws-status b/cws-status
index 8999aae..b6c1fff 100644
--- a/cws-status
+++ b/cws-status
@@ -35,8 +35,17 @@ EX_USAGE = 64
 EX_NOUSER = 67
 
 
+class ArgumentParser(argparse.ArgumentParser):
+
+    def error(self, message):
+        try:
+            super().error(message)
+        except SystemExit:
+            sys.exit(EX_USAGE)
+
+
 # Parse arguments.
-argparser = argparse.ArgumentParser(description='Query the publish status of \
+argparser = ArgumentParser(description='Query the publish status of \
     extensions on the Chrome Web Store dashboard.')
 argparser.add_argument(
     '--url',