D5813: revset: add expect to check the size of a set

[navaneeth.suresh (Navaneeth Suresh)]

navaneeth.suresh added a comment.


  > First, I think the word `expect` is too general. Perhaps, this should be called
  >  `expectsize()` or `expectlen()`.
  
  I can make it `expectsize()`.
  
  > It's also unclear what's the difference between `size` and `min`/`max`.
  >  Instead of these parameters, maybe we can add a `size` parameter that takes
  >  a number or a range `min:max`. See also the following patch.
  > 
  > https://www.mercurial-scm.org/pipermail/mercurial-devel/2019-February/127916.html
  
  Unfortunately, I can't see this in `hg-stable` which I was working.
  
  >> +        if len(rev) != n:
  >>  +            raise error.Abort(_('revset is not of expected size'))
  > 
  > Better to raise RepoLookupError so the error can be caught by `present(...)`.
  
  For sure. I could do that.
  
  >> +    return rev
  > 
  > You need to filter rev by subset. Since we'll probably want to get an ordered
  >  result from `expect(set)`, we'll have to conditionalize the filtering direction:
  > 
  >   if order == followorder:
  >       return subset & rev
  >   else:
  >       return rev & subset
  > 
  > 
  > You can try out some combinations of `expect(5:0) & 1:10` and
  >  `10:1 & expect(0:5)`.
  
  I got into many errors while using this. I might be not understanding this correctly. Could you please elaborate?

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5813

To: navaneeth.suresh, #hg-reviewers
Cc: yuja, pulkit, durin42, mjpieters, mercurial-devel