Mamba doesn't handle new-style lockfiles

[maresb]

Micromamba does, but Mamba seems to simply pass the job onto Conda, which fails to parse.

The following works upon replacing mamba→micromamba:

$ mamba install --yes --name base --file conda-lock.yml 
                  __    __    __    __
                 /  \  /  \  /  \  /  \
                /    \/    \/    \/    \
███████████████/  /██/  /██/  /██/  /████████████████████████
              /  / \   / \   / \   / \  \____
             /  /   \_/   \_/   \_/   \    o \__,
            / _/                       \_____/  `
            |/
        ███╗   ███╗ █████╗ ███╗   ███╗██████╗  █████╗
        ████╗ ████║██╔══██╗████╗ ████║██╔══██╗██╔══██╗
        ██╔████╔██║███████║██╔████╔██║██████╔╝███████║
        ██║╚██╔╝██║██╔══██║██║╚██╔╝██║██╔══██╗██╔══██║
        ██║ ╚═╝ ██║██║  ██║██║ ╚═╝ ██║██████╔╝██║  ██║
        ╚═╝     ╚═╝╚═╝  ╚═╝╚═╝     ╚═╝╚═════╝ ╚═╝  ╚═╝

        mamba (0.25.0) supported by @QuantStack

        GitHub:  https://github.com/mamba-org/mamba
        Twitter: https://twitter.com/QuantStack

█████████████████████████████████████████████████████████████

could not parse '- url: conda-forge' in: conda-lock.yml

CondaValueError: could not parse '- url: conda-forge' in: conda-lock.yml

[maresb]

@jvansanten, I haven't taken a look yet at how to solve this, but I'd hope it'd be easy to intercept this call when the extension is .y[a]ml and pass it along to libmamba? If so, that may be within my abilities, if I manage to find the time.

[jvansanten]

This appears to be because mamba simply kicks down to the install machinery from conda

mamba/mamba/mamba/mamba.py

Lines 353 to 372 in 94c179d

	if args.file:
	file_specs = []
	for fpath in args.file:
	try:
	file_specs += specs_from_url(fpath, json=context.json)
	except UnicodeError:
	raise CondaValueError(
	"Error reading file, file should be a text file containing"
	" packages \nconda create --help for details"
	)
	if "@EXPLICIT" in file_specs:
	explicit(
	file_specs,
	prefix,
	verbose=not (context.quiet or context.json),
	index_args=index_args,
	)
	return
	specs.extend(MatchSpec(s) for s in file_specs)

which has no idea what lock files are.

If

mamba/mamba/setup.py

Line 42 in 94c179d

long_description="A (hopefully faster) reimplementation of the slow bits of conda.",

is to be taken at face value, I don't think mamba should gain features that mainline conda doesn't have. Maybe a maintainer can comment, though.

[maresb]

Ya, very good point. On the other hand, it's awkward that micromamba contains functionality which mamba lacks. I'm curious to know what the maintainers think.

[jonashaag]

No new features for Mamba