Change toolchain override message from info to warn

[joshka]

Problem:
rustup currently logs an info-level message when a rust-toolchain.toml file overrides the active toolchain. This message is easy to miss in CI logs, leading to confusion when the expected toolchain (e.g., beta) isn’t being used.

Fix:
Promote the message about toolchain override (rust-toolchain.toml) from info to warn level, making it more visible during builds and CI runs.

Fix #4504

[djc]

I don't think this PR makes sense. Since the behavior is intended, displaying this as a warning violates a common expectation of what a warning means in most logging.

[joshka]

I don't think this PR makes sense. Since the behavior is intended, displaying this as a warning violates a common expectation of what a warning means in most logging.

I don't think that's the case here. This should be a warning because it's easy to miss that when you set the default toochain, but have an override then setting the default actually has no effect. This message is warning the user user that this configuration is nonsense and won't do what you expect from running commands that alter the default toolchain.

This is a very real problem that came from thinking that we were running some tasks against the beta toolchain, but actually weren't. Warnings in logging are often used to mark places like this that are possibly a problem but may not be, hence this is not an error.

[djc]

This should be a warning because it's easy to miss that when you set the default toochain, but have an override then setting the default actually has no effect. This message is warning the user user that this configuration is nonsense and won't do what you expect from running commands that alter the default toolchain.

From my perspective, this message is informing the user that rustup is executing on its configuration. I don't think rustup can decide whether that configuration is nonsense or not.

[joshka]

Strong opinion, weakly held disagreement with your perspective here.
Happy to close as I understand the problem.

[djc]

Strong opinion, weakly held disagreement with your perspective here. Happy to close as I understand the problem.

What part do you disagree with? How would we make the warning not annoying to people who have intentionally set up an override?