Re-sync _folds_ from start

Question

Vim has a handy feature in :syntax sync fromstart which allows me to fix syntax highlighting when it gets confused during an extended editing session. I map it to <leader>ss (reSync from Start) because I use it so often.

How would I achieve the same effect with code folding that uses a fold expression? From time-to-time, especially when commenting out areas of code, the folds will get out of sync with the actual buffer contents, and I'd be more than happy to wait the fraction of a second it would take Vim to recalculate the folds from scratch.

I'm happy for a short script if that's what it would take. I'm developing my vimscript-fu and would be happy for the exercise :)

Answer 1

It sounds like you're looking for zx or zX.

From the Vim documentation on fold,

zx
Update folds: Undo manually opened and closed folds: re-apply 'foldlevel', then do "zv": View cursor line. Also forces recomputing folds. This is useful when using 'foldexpr' and the buffer is changed in a way that results in folds not to be updated properly.

zX
Undo manually opened and closed folds: re-apply 'foldlevel'. Also forces recomputing folds, like |zx|.