This looks like it adds a lot of complexity for a fairly niche feature.

Is there a reason we can't just use WalkBuilder::override for this?

I initially tried using WalkBuilder::overrides for this, but the ignore crate's Override::matched() has an implicit blacklist behavior that prevents it.

When you add any whitelist pattern to OverrideBuilder, every non-matching file is force-excluded (Match::Ignore) instead of falling through (Match::None). So for example whitelisting node_modules would hide every other file in the tree. There's no flag to disable this it's hardcoded.

The two-walk approach avoids this by keeping Walk 1 completely unchanged and only running Walk 2 when --override-ignore is actually used, so there's zero cost for normal usage.

Open to simpler approaches if I'm missing something!