TOML: alternative for generative env and factor?

[abelcheung]

Facing some hurdle here when migrating ini to toml. Without generative env and factor support, I found myself creating lots of repetitive and almost identical envs, differed by only 1 or 2 keys. For example:

[env._basic]
change_dir = '{toxroot}/dir'
commands_pre = [['some', 'command']]
commands = [['other', 'looooong', 'command']]

[env.env1]
dependency_groups = ['a', 'b']
change_dir   = {replace = 'ref', of = ['env', '_basic', 'change_dir'  ]}
commands_pre = {replace = 'ref', of = ['env', '_basic', 'commands_pre']}
commands     = {replace = 'ref', of = ['env', '_basic', 'commands'    ]}

[env.env2]
dependency_groups = ['a', 'c']
change_dir   = {replace = 'ref', of = ['env', '_basic', 'change_dir'  ]}
commands_pre = {replace = 'ref', of = ['env', '_basic', 'commands_pre']}
commands     = {replace = 'ref', of = ['env', '_basic', 'commands'    ]}

[env.env3]
dependency_groups = ['a', 'd']
change_dir   = {replace = 'ref', of = ['env', '_basic', 'change_dir'  ]}
commands_pre = {replace = 'ref', of = ['env', '_basic', 'commands_pre']}
commands     = {replace = 'ref', of = ['env', '_basic', 'commands'    ]}

# ..... (and so on) .....

Currently [env_run_base] is not a good option as I have 2 large groups of envs, one following a set of defaults and another following another set of defaults. Is there any other option to simplify the mess?

[gaborbernat]

You can change the base environment key via https://tox.wiki/en/latest/config.html#base.

[abelcheung]

Thanks, it worked wonders! Envs become much more manageable by combining various bases now. Wish I notice this setting earlier.