Add pub run build_runner update command?

[matanlurey]

Something to just ensure that the build script is up to date, but does nothing else.

This will be useful for CLIs that wrap/delegate and perform a "doctor"-like command.

(Happy to add this, just want a 👍 first)

[matanlurey]

Also if this is added, I'd like to make pub run build_runner just show commands, and not ensure that the build script is updated. It's a little confusing today because you pass no commands, but some work happens.

[natebosch]

I'm not sure we want to to use update for this. I think the usage should be rare, so I'm inclined to use a longer command name. How about pub run build_runner generate-entrypoint?

I'm in favor of not generating the entrypoint when no command is given, but I'm not sure how we'd implement that. We might need to duplicate knowledge of the run commands in the wrapping binary.

[matanlurey]

I mean we can even make it a hidden command if you want, meant for other tools, not users:

$ pub run build_runner ensure-build-script

... ?

@natebosch:

but I'm not sure how we'd implement that

Unless I'm mistaken, can't we just not run ensureBuild() unless you choose test/serve/watch?

[natebosch]

Unless I'm mistaken, can't we just not run ensureBuild() unless you choose test/serve/watch?

Skipping the generation is easy :) I'm only worried about printing the help string.

The code that runs ensureBuild() doesn't use the same arg parsing logic as the code that actually does the build. I suppose though that we can just refer to the arg parser that the generated script would use.

[jakemac53]

@matanlurey I am curious what is the primary motivation behind this request? I am not sure what the value is of just creating the build script itself since we would do that again at the start of any meaningful action anyways.