Move the did_you_mean spellchecker to require-time

[gsamokovarov]

This change conditionally defines Rails::Command::Spellchecker based
on the did_you_mean presence in require time, so we don't have the
condition executing at runtime.

[rails-bot]

r? @schneems

(@rails-bot has picked a reviewer for you, use r? to override)

[utilum]

Smart :)

[kaspth]

I find this harder to grok than the existing code. What's this costing us at runtime?

[sikachu]

I seconded @kaspth comment. I wonder if we separate our own spellchecker and this file it'll make it much more cleaner (so this file would only do the conditional to see if did_you_mean exists or not, and if not it just call our new class).

[matthewd]

I'm still dubious about the benefit of us using DYM here at all. When it meant we didn't have to maintain our own implementation (#32289), sure.. but now (#32781), I think any incremental gain we receive from some future DYM improvement is likely outweighed by the fact we're adapterizing something that just doesn't matter -- AFAIK we're not even testing both implementations?

[kaspth]

@matthewd agreed, let's just kill it 👍

[gsamokovarov]

Cool, will drop the whole did_you_mean thing.

[rails-bot]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[gsamokovarov]

The gentle bot nudge made me wanna finish this PR and remove the did_you_mean dependency, but I found out we have a feature that depends on the did_you_mean algorithm.

With the Levenstein algorithm, we always had suggestions as the first ones in the list are the closest ones to the given input. did_you_mean's spell checker is smart enough to give up and return no suggestions when they will be far from the truth. fb173b6

What do you folks think, is it worth it to remove the feature above and drop the did_you_mean implicit dependency or continue as we are now? I think dropping the constant nagging of Maybe you meant is worth the did_you_mean dependency, so I'm closing this PR now for now. Reopen if you think otherwise.

[kaspth]

@gsamokovarov all good ✌️