Code collapse gets stuck collapsed with Undo

[JeffryBooher]

1. Create a new js file
2. Add the following code block:

 /**
   * Returns the thing
   * 
   */
function getTheThing() {
     var s = blah();
     return s.execute();
}

 /**
   * Returns more things
   * 
   */
function getMoreThings() {
     var s = blah();
     return s.execute();
}

3 . now wrap the block with /* */

You should end up with something like this:

/*
 /**
   * Returns the thing
   * 
   */
function getTheThing() {
     var s = blah();
     return s.execute();
}

 /**
   * Returns more things
   * 
   */
function getMoreThings() {
     var s = blah();
     return s.execute();
}
*/

you should get a collapse disclosure beside the topmost /*

4 . collapse the block 5 . undo

cannot expand the block

While trying to find the steps to this I was occasionally unable to reproduce this but i did get it to reproduce if I added the closing */ first then the opening comment /*, collapsed then undo so you might want to try it both ways.

[thehogfather]

Thanks that an interesting one - and very easy to reproduce. It is easy to see how the undo changes the state of the folding regions - and this issue goes right down into the code-mirror addon for folding. So, from a user point of view perhaps it make sense to automatically unfold folded regions that no longer exist? i.e., when you do an undo or delete the char that closes a fold region, if the region is folded, then it should be expanded.

[JeffryBooher]

That's what i was thinking as well but you could also ague that the outer /* */ is invalid and shouldn't be collapsible. Not sure if that solves the issue or not but something to think about.

[thehogfather]

Indeed because the concept of nesting is ubiquitous. e.g., nested functions, JS object literals etc. So it is even reproducible using:

function () {
function() {

}}

Collapse the outermost function and delete the last brace. For now I have a fix that auto expands the invalid range. I will push once I'm reasonably convinced it doesnt break anything else.