view tests/test-ancestor.py.out @ 40745:300f8564220f

tags: cache `repo.changelog` access when checking tags nodes

The tags reading process checks if the nodes referenced in tags exist. Caching
the access to `repo.changelog` provides a large speedup for repositories with
many tags.

running `hg perftags` in a large private repository
before: ! wall 0.393464 comb 0.390000 user 0.330000 sys 0.060000 (median of 25)
after:  ! wall 0.267711 comb 0.270000 user 0.210000 sys 0.060000 (median of 38)

% lazy ancestor set for [], stoprev = 0, inclusive = False
membership: []
iteration:  []
% lazy ancestor set for [11, 13], stoprev = 0, inclusive = False
membership: [7, 8, 3, 4, 1, 0]
iteration:  [8, 7, 4, 3, 2, 1, 0]
% lazy ancestor set for [1, 3], stoprev = 0, inclusive = False
membership: [1, 0]
iteration:  [1, 0]
% lazy ancestor set for [11, 13], stoprev = 0, inclusive = True
membership: [11, 13, 7, 8, 3, 4, 1, 0]
iteration:  [13, 11, 8, 7, 4, 3, 2, 1, 0]
% lazy ancestor set for [11, 13], stoprev = 6, inclusive = False
membership: [7, 8]
iteration:  [8, 7]
% lazy ancestor set for [11, 13], stoprev = 6, inclusive = True
membership: [11, 13, 7, 8]
iteration:  [13, 11, 8, 7]
% lazy ancestor set for [11, 13], stoprev = 11, inclusive = True
membership: [11, 13]
iteration:  [13, 11]
% lazy ancestor set for [11, 13], stoprev = 12, inclusive = True
membership: [13]
iteration:  [13]
% lazy ancestor set for [10, 1], stoprev = 0, inclusive = True
membership: [2, 10, 4, 5, 0, 1]
iteration:  [10, 5, 4, 2, 1, 0]