tests/test-issue842.t

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.

https://bz.mercurial-scm.org/842

  $ hg init
  $ echo foo > a
  $ hg ci -Ama
  adding a

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo bar > a

Should issue new head warning:

  $ hg ci -Amb
  adding a
  created new head

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo stuffy > a

Should not issue new head warning:

  $ hg ci -q -Amc

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo crap > a
  $ hg branch testing
  marked working directory as branch testing
  (branches are permanent and global, did you want a bookmark?)

Should not issue warning:

  $ hg ci -q -Amd