scripts_regression_tests.py does not take command line --machine arguments

[jhkennedy]

When trying to run the CIME regression tests on my linux desktop, using this command:

./scripts_regression_tests.py --machine linux-generic 2>&1 

I get this error:

ERROR: Could not initialize machine object from $CIME/config/acme/machines/config_machines.xml or $HOME/.cime/config_machines.xml

Note: This occurs in both ACME/cime and ESMCI/cime.

It looks like this error is caused by:

cime/scripts/tests/scripts_regression_tests.py

Line 34 in 2d39e61

MACHINE = Machines()

where the Machines() class is initialized upon import, before the _main_func() is run, causing this expect to fail

cime/scripts/lib/CIME/XML/machines.py

Lines 45 to 51 in 2d39e61

	if machine is None:
	if "CIME_MACHINE" in os.environ:
	machine = os.environ["CIME_MACHINE"]
	else:
	machine = self.probe_machine_name()
	expect(machine is not None, "Could not initialize machine object from {} or {}".format(infile, local_infile))

and the regression tests to never reach the handling of the command line arguments in _main_func():

cime/scripts/tests/scripts_regression_tests.py

Lines 2464 to 2472 in 2d39e61

	if "--machine" in sys.argv:
	midx = sys.argv.index("--machine")
	mach_name = sys.argv[midx + 1]
	MACHINE = Machines(machine=mach_name)
	os.environ["CIME_MACHINE"] = mach_name
	del sys.argv[midx + 1]
	del sys.argv[midx]

---

Possible Fix:

This could be fixed by deleting the initialization on import:

cime/scripts/tests/scripts_regression_tests.py

Line 34 in 2d39e61

MACHINE = Machines()

and changing the --machine option handling in _main_func() to:

    if "--machine" in sys.argv:
        midx = sys.argv.index("--machine")
        mach_name = sys.argv[midx + 1]
        MACHINE = Machines(machine=mach_name)
        os.environ["CIME_MACHINE"] = mach_name
        del sys.argv[midx + 1]
        del sys.argv[midx]
    else:
        MACHINE = Machines()

I don't see any place that ./scripts_regression_tests.py is imported in CIME or ACME, so there is no need as far as I can tell to initialize MACHINE on import.

---

Note: it might be a good idea to change the options handling here to argparse as well.

[jedwards4b]

Set CIME_MACHINE=yourmachinename before running scripts_regression_tests.py

There were problems with using argparse in scripts_regression_tests.py

[jhkennedy]

@jedwards4b That is also a fix, but still requires changes to CIME. That is, if that's the expected use, the machine option should be removed (it is non-functional right now) and the error message or documentation should also tell you to set the CIME_MACHINE environment variable.

Interesting about argparse; do you remember what the problems were?

[jedwards4b]

I think that argparse was incompatible with the unittest argument handling mechanism.
I would encourage you to issue a PR with the changes you suggest.