How to identify conda package dependents?

Question

For a given conda package, how to I list the packages that depend on it?

I recently installed anaconda on a university cluster that al

Answer 1

Based on Yann's answer, code diving in conda core and reading this I came up with the following script to get a reverse-dependency graph of all cached channels:

import glob
import json
import os

from collections import defaultdict

info = json.load(os.popen('conda info --json'))

print('Loading channels...')
channels = [
    json.load(open(repodata))
    for pkg_dir in info['pkgs_dirs']
    for repodata in glob.glob(os.path.join(pkg_dir, 'cache', '*.json'))
]
print('Done')

rdeps = defaultdict(set)

for c in channels:
    for k, v in c['packages'].items():
        package = '-'.join(k.split('-')[:-2])
        for dep in v['depends']:
            dependant = dep.split()[0]
            rdeps[dependant].add((package, c['_url']))

Now you can get the reverse dependencies of a specific package:

>>> print(rdeps['mpich2'])
set()

Well, right now nothing depends on it anymore... But if you run it in ipython or Jupyter, you can then quickly query the reverse dependencies, e.g.:

>>> print(rdeps['aiosqlite'])
{('databases', 'https://conda.anaconda.org/conda-forge/linux-64')}

You get the package name (without versions, of which there may be many), and the channel URL (which can show you, if it's pkgs/main/(arch) or conda-forge etc.