A hacky script for using mamba to determin the first conda package that leads to an unsolvable environment

conda_first_failure.py

#!/usr/bin/env python
import subprocess
import os

subdir = 'osx-64'

specs = ['python=3.9.*',
         'setuptools',
         'cython',
         'libcdms',
         'numpy=1.19.*',
         'libnetcdf=4.8.1.*=nompi_*',
         'cdat_info',
         'libdrs_f',
         'jasper=1.*']

base_command = ['mamba', 'create', '-y', '-n', 'test', '--dry-run']

prevEnd = None
highestValid = -1
lowestInvalid = len(specs)
endIndex = len(specs)
while highestValid != lowestInvalid-1:
    subset_specs = specs[0:endIndex]
    print('last: {}'.format(subset_specs[-1]))

    command = base_command + subset_specs

    try:
        env = dict(os.environ)
        env['CONDA_SUBDIR'] = subdir
        subprocess.check_call(command, stdout=subprocess.DEVNULL, env=env)
        highestValid = endIndex-1
        endIndex = int(0.5 + 0.5*(highestValid + lowestInvalid)) + 1
        print('  Succeeded!')
    except subprocess.CalledProcessError:
        lowestInvalid = endIndex-1
        endIndex = int(0.5 + 0.5*(highestValid + lowestInvalid)) + 1
        print('  Failed!')
    print('  valid: {}, invalid: {}, end: {}'.format(
        highestValid, lowestInvalid, endIndex))

if lowestInvalid == len(specs):
    print('No failures!')
else:
    print('First failing package: {}'.format(specs[lowestInvalid]))