smartset: convert set to list lazily If the caller only wants to construct a baseset via a set, and then do "__contains__" tests. It's unnecessary to initialize the list. Testing on my unfiltered hg-committed repo where len(draft()) is 2600, this patch shows about 6% improvement on set intensive queries: Before: $ for i in `seq 5`; hg perfrevset 'draft() & draft() & draft() & draft()' ! wall 0.001196 comb 0.000000 user 0.000000 sys 0.000000 (best of 2011) ! wall 0.001191 comb 0.000000 user 0.000000 sys 0.000000 (best of 2099) ! wall 0.001186 comb 0.010000 user 0.010000 sys 0.000000 (best of 1953) ! wall 0.001182 comb 0.000000 user 0.000000 sys 0.000000 (best of 2135) ! wall 0.001193 comb 0.000000 user 0.000000 sys 0.000000 (best of 2177) After: $ for i in `seq 5`; hg perfrevset 'draft() & draft() & draft() & draft()' ! wall 0.001128 comb 0.000000 user 0.000000 sys 0.000000 (best of 2247) ! wall 0.001119 comb 0.000000 user 0.000000 sys 0.000000 (best of 2317) ! wall 0.001115 comb 0.000000 user 0.000000 sys 0.000000 (best of 2244) ! wall 0.001131 comb 0.000000 user 0.000000 sys 0.000000 (best of 2093) ! wall 0.001124 comb 0.000000 user 0.000000 sys 0.000000 (best of 2134) It could have bigger impact on larger sets in theory.