To warn or to error, that is the question

[MilesCranmer]

This is a question for the community. What should be the default behavior of a @stable-ized function encountering type instability?

• 🎉 Error (current behavior; default_mode="error")
• 👀 Warning (default_mode="warn")

Comparison:

• Advantages of error: (i) refuses to run with any type instability. It's sort of like the Rust compiler in that it guarantees certain behavior; (ii) does not flood the REPL output with messages as you just exit immediately.
• Advantages of warning: (i) does not quit on the first instability, displays a warning for each unstable function throughout the stacktrace, which makes it easier to track down issues; (ii) allows you to run code without needing the allow_unstable function.

However, what should the default be? You can always set the default_mode yourself, or set it via Preferences.jl. If you have a particular point to would like to add you can comment it, otherwise please just vote using emojis (🎉 or 👀 )

[MilesCranmer]

Okay this is pretty one-sided in the favor of "error" by 5 votes to 0. So we'll keep it that way.