Changing short / long / env precedence

[incendium]

Is it possible to have arguments from the environment take precedence over those provided via the command line using derive? For context, I have a binary that is being set as a Dockerfile entrypoint and I allow both CLI arguments or environment variables to set options.

[epage]

There is not a way at this time to change the precedence.

[incendium]

Appreciate the quick response. Is this something that might be considered in the future?

[epage]

Clap has a tension between adapting to meet people's needs and not over-burdening existing users with longer compile times, bigger binaries, and harder to discover APIs in the docs.

Lately, we've been approaching this problem by focusing the easy path on what should be the common behavior and finding general solutions that can then be reused across multiple problems. That effort is being coordinated in #3476.

So without waiting on #3476, the likely solution is to see if the default behavior can be changed. Even that would have to wait for 5.0 but we could implement it behind the unstable-v5 feature flag. The question then is what is the right / expected order for layering CLI and env.