[PATCH stable] revset: don't cache abstractsmartset min/max invocations infinitely

[Yuya Nishihara]

On Tue, 25 Oct 2016 18:57:26 +0200, Mads Kiilerich wrote:
> # HG changeset patch
> # User Mads Kiilerich <madski at unity3d.com>
> # Date 1477414587 -7200
> #      Tue Oct 25 18:56:27 2016 +0200
> # Branch stable
> # Node ID c2fe58cd4235fc6c8cabea882794303d620bec3a
> # Parent  76c57e1fe79b0980b377b4f305635dea393d6315
> revset: don't cache abstractsmartset min/max invocations infinitely
> 
> There was a "leak", apparently introduced in ab66c1dee405. When running:
> 
>     hg = hglib.open('repo')
>     while True:
>         hg.log("max(branch('default'))")
> 
> all filteredset instances from branch() would be cached indefinitely by the
> @util.cachefunc annotation on the max() implementation.

Indeed. We've cached {self: v} pair every time max() was called.
Queued this for stable, thanks.

> -    @util.cachefunc
>      def min(self):
>          """return the minimum element in the set"""
> -        if self.fastasc is not None:
> -            for r in self.fastasc():
> -                return r
> -            raise ValueError('arg is an empty sequence')
> -        return min(self)
> -
> -    @util.cachefunc
> +        if self.fastasc is None:
> +            v = min(self)
> +        else:
> +            for v in self.fastasc():
> +                break
> +            else:
> +                raise ValueError('arg is an empty sequence')
> +        self.min = lambda: v
> +        return v

I slightly prefer using propertycache() and wrap it by a function, which
is a common pattern seen in context.py, but that's just a nitpicking.