revset: remove "small" argument from "_optimize"...
revset: remove "small" argument from "_optimize"
`_optimize` calculates weights of subtrees. "small" affects some weight
calculation (either 1 or 0.5). The weights are now only useful in `and`
optimization where we might swap two arguments and use `andsmally`.
In the real world, it seems unlikely that revsets with weight of 0.5 or 1
matters the `and` order optimization. I think the important thing is to get
weights of expensive revsets right (ex. `contains`).
This patch removes the `small` argument to simplify the interface.
As for choosing between 0.5 vs 1, things returning a single revision
(`ancestor`, `string`) has a weight of 0.5. Things returning multiple
revisions returns 1. This could be sometimes useful in the `andsmally`
optimization, ex.
(((:)-2) & expensive()) & ((1-2) & expensive())
^^^ ^
^^^^^^^ ^^^^^
^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^
weight=1 weight=0.5
would have an `andsmally` optimization so `1-2` gets executed first, which
seems to be desirable.
Differential Revision:
https://phab.mercurial-scm.org/D656
