comparison tests/test-revset.t @ 35501:12a46ad67a3c

smartset: split generatorset classes to avoid cycle

I uncovered a cycle manifesting in a memory leak by running
`hgperfrevset '::tip'`. The cycle was due to generatorset.__init__
assigning a bound method to self.__contains__. Internet sleuthing
revealed that assigning a bound method to an instance attribute
always creates a cycle.

This commit creates two new variants of generatorset for the special
cases of ascending and descending generators. The special
implementations of __contains__ have been extracted to these classes
where they are defined as __contains__.

generatorset now implements __new__ and changes the spawned type to
one of the new classes if needed.

Differential Revision: https://phab.mercurial-scm.org/D1780

35500:87918218da70

Test scmutil.revsingle() should return the last revision

  $ hg debugrevspec -s 'last(0::)'
  * set:
  <baseset slice=0:1
    <generatorset->>
  9
  $ hg identify -r '0::' --num
  9

Test matching

35501:12a46ad67a3c

Test scmutil.revsingle() should return the last revision

  $ hg debugrevspec -s 'last(0::)'
  * set:
  <baseset slice=0:1
    <generatorsetasc->>
  9
  $ hg identify -r '0::' --num
  9

Test matching