In v2.5.0 if you override do_help() and don't use the @with_argparser decorator you get an error #1383

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1. tleonhardt commented on Nov 19, 2024

   

   tleonhardt

   on Nov 19, 2024

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   @kmvanbrunt You have the most insight into the changes made in 2.5.0. Would you have any insight into what changed in terms of finding help text to display?
2. kmvanbrunt commented on Nov 19, 2024

   

   kmvanbrunt

   on Nov 19, 2024

   Last edited by kmvanbrunt

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   This is the error I get when testing tomcatmanager.

   if arg_parser is None:
       # This shouldn't be possible to reach
       raise ValueError(f'No argument parser found for {command_name}')  # pragma: no cover

   Since kotfu is overriding do_help() as a non-argparse decorated method, Cmd._register_command_parser() never creates a parser for cmd2's do_help(). Therefore, when kotfu calls super().do_help(), the decorator runs and finds no parser.

   We need to make sure Cmd._register_command_parser() creates a parser for each of the base class do_xxx methods.
3. kotfu commented on Nov 19, 2024

   

   kotfu

   on Nov 19, 2024

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   Other options I could consider include:

   a) using the @with_argparser decorator on my overridden do_help() method
   b) completely reimiplementing do_help(), ie don't ever call super().do_help()

   Also, with this new information, I'm rewriting the issue description....
4. kotfu

   changed the title [-]v2.5.0 introduces an undocumented breaking change for custom arg parsers[/-] [+]In v2.5.0 if you override `do_help()` and don't use the `@with_argparser` decorator you get an error[/+] on Nov 19, 2024
5. kmvanbrunt commented on Nov 19, 2024

   

   kmvanbrunt

   on Nov 19, 2024

   Last edited by kmvanbrunt

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   @kotfu You don't need to change anything. It's a bug in cmd2.

   The same problem will occur if you override do_help(), decorate it using with_argparser, and supply a parser with different arguments than what super().do_help() is expecting. The moment you call super().do_help(), it will look up the parser by command name and get the parser for your do_help().

   A major improvement to cmd2 2.5.0 is making parsers instance variables instead of class variables. The concept is backward compatible, but unfortunately the implementation needs a fix. The problem is the parser dictionary is keyed by command name. To handle overriding functions, it needs to be keyed by the function the parser belongs to.

   Give us a few days and the fix will be in cmd2 2.5.7.

   Sorry for breaking tomcatmanager.
6. kmvanbrunt

   closed this as completedin #1384on Nov 22, 2024
7. kmvanbrunt commented on Nov 23, 2024

   

   kmvanbrunt

   on Nov 23, 2024

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   @kotfu cmd2 2.5.7 is out.

   I tested it with tomcatmanager and the help commands worked.