helics_recorder (but not helics_app) limited command-line parsing

[trevorhardy]

Describe the bug
helics_recorder (and probably helics_player, potentially many others), don't appear to parse command-line options as flexibly as we intend. Specifically, it appears spaces of any kind in the options are causing problems. For example, -o output.txt produces the error below.

Input:

helics_recorder recorder_config.txt --output recorder_output.txt 

Output:

libc++abi: terminating due to uncaught exception of type CLI::ArgumentMismatch: --output: 1 required TEXT missing

What is the expected behavior?
The --help indicates -o and --output= should be equally valid but, through testing, we found that putting any space after the option (-o or --output) produces the above error.

Works:

helics_recorder recorder_config.txt --output=recorder_output.txt 
helics_recorder recorder_config.txt -orecorder_output.txt 

Doesn't work:

helics_recorder recorder_config.txt --output recorder_output.txt 
helics_recorder recorder_config.txt -o recorder_output.txt 

To Reproduce
Steps to reproduce the behavior:
Change the fundamental default example runner file to add a helics_recorder:

{
  "name": "fundamental_default",
  "broker": true,
  "federates": [
    {
      "directory": ".",
      "exec": "python -u Charger.py 1",
      "host": "localhost",
      "name": "Charger"
    },
    {
      "directory": ".",
      "exec": "python -u Battery.py 1",
      "host": "localhost",
      "name": "Battery"
    },
    {
      "directory": ".",
      "exec": "helics_recorder recorder_config.txt -o recorder_output.txt",
      "host": "localhost",
      "name": "helics_recorder"
    }
  ]
}

Environment (please complete the following information):

• Operating System: macOS 14.7.2
• Language Extension: Python
• what compiler or setup process did you use: build from source + pip install helics

$ helics --version

helics, version 3.6.0

Python HELICS version 3.6.0

HELICS Library version 3.6.0 (2024-12-09)

HELICS Apps version 3.6.0

$ helics_app --version

Additional context and information
Co-incidentally, during the testing for #2723, we found that "helics_app" (rather than "helics_recorder") didn't seem to exhibit this problem.

[trevorhardy]

Fixed in #2726