comparison tests/test-revset2.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

        (symbol 'ancestors')
        (symbol '4'))))
  * set:
  <addset
    <baseset- [1, 3, 5]>,
    <generatorset+>>
  5
  3
  1
  0
  2

          (dagrange
            (symbol '1')
            (symbol '5'))))))
  * set:
  <addset+
    <generatorset+>,
    <baseset- [1, 3, 5]>>
  0
  1
  2
  3

    (symbol 'descendants')
    (func
      (symbol 'merge')
      None))
  * set:
  <generatorset+>
  6
  7

test infinite recursion

35501:12a46ad67a3c

        (symbol 'ancestors')
        (symbol '4'))))
  * set:
  <addset
    <baseset- [1, 3, 5]>,
    <generatorsetdesc+>>
  5
  3
  1
  0
  2

          (dagrange
            (symbol '1')
            (symbol '5'))))))
  * set:
  <addset+
    <generatorsetdesc+>,
    <baseset- [1, 3, 5]>>
  0
  1
  2
  3

    (symbol 'descendants')
    (func
      (symbol 'merge')
      None))
  * set:
  <generatorsetasc+>
  6
  7

test infinite recursion