pintk can swap inputs

[dlakaplan]

Previously if you fed pintk the timfile and parfile in the wrong order, it would fail with an opaque message:

(pintdev) kaplan@plock[~/pythonpackages/PINT_dlakaplan] (master) % pintk tests/datafile/NGC6440E.tim tests/datafile/NGC6440E.par -vv
INFO     (pint.pintk.pulsar             ): Loading pulsar parfile: tests/datafile/NGC6440E.tim                                      
Traceback (most recent call last):
  File "/Users/kaplan/opt/anaconda3/envs/pintdev/bin/pintk", line 33, in <module>
    sys.exit(load_entry_point('pint-pulsar', 'console_scripts', 'pintk')())
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/scripts/pintk.py", line 267, in main
    app = PINTk(
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/scripts/pintk.py", line 51, in __init__
    self.openPulsar(
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/scripts/pintk.py", line 153, in openPulsar
    self.psr = Pulsar(parfile, timfile, ephem, fitter=fitter)
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/pintk/pulsar.py", line 74, in __init__
    self.prefit_model = pint.models.get_model(self.parfile)
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/models/model_builder.py", line 708, in get_model
    model = model_builder(
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/models/model_builder.py", line 187, in __call__
    self._setup_model(
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/models/model_builder.py", line 646, in _setup_model
    timing_model.validate(allow_tcb=allow_tcb)
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/models/timing_model.py", line 433, in validate
    self.validate_component_types()
  File "/Users/kaplan/pythonpackages/PINT_dlakaplan/src/pint/models/timing_model.py", line 456, in validate_component_types
    assert (
AssertionError: Model must have one and only one spindown component (Spindown or another subclass of SpindownBase).

Now it will look and if the extensions are flipped, it will swap the inputs:

(pintdev) kaplan@plock[~/pythonpackages/PINT_dlakaplan] (pintkargs) % pintk tests/datafile/NGC6440E.tim tests/datafile/NGC6440E.par -vv
DEBUG    (pint.scripts.pintk            ): Swapping inputs: parfile='tests/datafile/NGC6440E.par' and timfile='tests/datafile/NGC6440E.tim'

If the extensions otherwise don't match the expected values it will note that as log.INFO but still try to proceed. This could still be used as a clue that there is something wrong if pintk fails.

[codecov]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (334fab7) 68.49% compared to head (88ceb69) 68.47%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1656      +/-   ##
==========================================
- Coverage   68.49%   68.47%   -0.02%     
==========================================
  Files         104      104              
  Lines       24267    24276       +9     
  Branches     4330     4333       +3     
==========================================
+ Hits        16622    16624       +2     
- Misses       6558     6565       +7     
  Partials     1087     1087              

Files	Coverage Δ
src/pint/scripts/pintk.py	23.28% <22.22%> (-0.07%)	⬇️

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[abhisrkckl]

Is this necessary? Wouldn't it be better just to have informative error messages?

[dlakaplan]

No, it's not necessary. But while writing an informative error message I realized that this would be just as easy.

[dlakaplan]

@scottransom : what do you think about this? I get the input order wrong about half of the time, and this change would make it easier. But I could also just change it to a more sensible error message.

[scottransom]

I like it. And I also make that mistake sometimes. Given the dynamic nature of Python, it seems like a good idea to me. And I don't see how this is likely to mess anything up.