Mercurial > hg-stable
changeset 24936:2aa94b6fe51c
revset: make generatorset.__nonzero__ lazy
The 'for r in self:' call could trigger full consumption of the generator while
we only need a single value. We also fast path if a single value got already
computed. See inline comment for more details.
This provide massive speedup for lazy operation using boolean testing.
max(::tip)
e5b507efb36e) wall 0.055609 comb 0.060000 user 0.060000 sys 0.000000 (best of 100)
after change) wall 0.000109 comb 0.000000 user 0.000000 sys 0.000000 (best of 19146)
| author | Pierre-Yves David <pierre-yves.david@fb.com> |
|---|---|
| date | Mon, 04 May 2015 12:36:48 -0700 |
| parents | 3035b75cd594 |
| children | f5518b47cdd1 |
| files | mercurial/revset.py |
| diffstat | 1 files changed, 6 insertions(+), 1 deletions(-) [+] |
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--- a/mercurial/revset.py Tue May 05 15:33:01 2015 -0700 +++ b/mercurial/revset.py Mon May 04 12:36:48 2015 -0700 @@ -3137,7 +3137,12 @@ self.__contains__ = self._desccontains def __nonzero__(self): - for r in self: + # Do not use 'for r in self' because it will enforce the iteration + # order (default ascending), possibly unrolling a whole descending + # iterator. + if self._genlist: + return True + for r in self._consumegen(): return True return False