CLI: Toggle default output format based on the number of violations

[zanieb]

In #7349 and #7352 the default output of ruff check includes much more content. However, this comes with a performance degradation for large numbers of violations as computing the display of source and fixes is expensive. A possible solution is to toggle the default output format between "full" and "concise" (#7350) depending on the number of detected violations. If we see more than 30 violations (for example), we should switch to the concise output. If --format full or --format concise is provided explicitly (or in the configuration file) we should always respect the given format regardless of the number of violations.

[MichaReiser]

If --format full or --format concise is provided explicitly (or in the configuration file) we should always respect the given format regardless of the number of violations.

I'm undecided on this. I think the use case here is that sometimes it's desired to get the full output, even if computing the output takes a long or prints a lot of text (e.g., when piping in CI). However, I'm concerned that the default full (no configuration) behavior is different from the explicit `output-format: full.

The main motivation for truncating fixes (we could, for example, print the first n violations in full, then print a message that Ruff has switched to concise) is to protect users from being overwhelmed and having a "slow" experience. I think I would want that protection even when I explicitly say that I want the full output format.

One less implicit solution would be to define a new full-always or similar output format.

[zanieb]

I think I would want that protection even when I explicitly say that I want the full output format.

I don't really follow this, why? If you explicitly request the full format it seems weird that we would not respect that.

However, I'm concerned that the default full (no configuration) behavior is different from the explicit output-format: full.

We would encode the default behavior with a separate key like "auto" or "default" instead of overloading "full" to have two separate behaviors.

[MichaReiser]

I don't really follow this, why? If you explicitly request the full format it seems weird that we would not respect that.

Because I understood that having the "automatic" output format (that switches between full and concise) and the "full" output format use the same configuration name. But that's not the case according to:

We would encode the default behavior with a separate key like "auto" or "default" instead of overloading "full" to have two separate behaviors.

So I'm okay with printing all diagnostics when explicitly requesting full (and not auto)