Reframe use of --isolated in tool run

[charliermarsh]

Summary

This PR gets rid of the global --isolated flag (which serves a bunch of independent responsibilities right now) on uv tool run in favor of a dedicated --isolated flag, which tells uv to avoid re-using an existing tool environment for this invocation. We'll add the same thing to uv run, to avoid using the base project environment.

This will become a bit clearer in #5466, when we deprecate the --isolated flag on the preview APIs.

[zanieb]

What's the idea behind "isolate" vs "isolated"? What tense do we want to use in our CLI?

[charliermarsh]

I suppose we could use --isolated. I wanted to have a hard break with the deprecated flag, otherwise in a vacuum I would've just used --isolated. Let me skim our CLI and see if we have examples either way...

[zanieb]

Yeah I worry about using a different name than we would have just for the deprecation :/ it makes some sense pragmatically but I am also genuinely curious which tense we should use in general.

[charliermarsh]

It looks like we tend to use imperative: --refresh, --reinstall, --annotate, --generate-hashes

[charliermarsh]

On the other hand, we have --locked.

[charliermarsh]

Although --locked isn't an action (it's not telling you to lock something), it's a description... Whereas --isolate is telling uv to add isolation. I don't know if I'm smart enough to describe the distinction accurately.

[zanieb]

I think I feel the gist of what you're getting at.

I think if we consider --locked (and similar) as "descriptions of how to act" rather than "doing another action" (as would be implied by --lock), I think --isolated actually makes more sense because we're doing the same action just in a different way?

[charliermarsh]

Yeah that's a good description. Ok, should we just reuse --isolated here? It's not a huge problem since --isolated already meant this in these contexts. It just makes the deprecation and warnings more difficult to implement...

[zanieb]

I think we would use it if not for the existing flag; and, since it's the same as before and mostly in preview, I think we should go for it. Sorry it adds complexity 😬 hopefully the deprecation is short-lived? I'm also okay with no-deprecation in the preview commands.

[charliermarsh]

I'm not 100% sure how to make it work since we'll now have --isolated as both a global and an argument on a dedicated command (assuming we want it to show up in help). I'll try though.

[charliermarsh]

Oh interesting, Clap lets commands override global arguments. Ok, that's easier...