narrow: validate patterns on incoming bundle2 part The remote data is untrusted and needs to be validated for pattern conformance. Differential Revision: https://phab.mercurial-scm.org/D4525

narrowspec: validate patterns when loading and saving spec file Patterns should be normalized and validated before being passed into narrowspec.save(). Let's assert that by checking immediately before writing the narrow spec file. And let's assert that patterns loaded from the spec file also conform. Differential Revision: https://phab.mercurial-scm.org/D4524

ancestor: use heapreplace() in place of heappop/heappush() This should be slightly faster. Overall perfancestors result:: cpython nginx mercurial ------------- ---------------- ---------------- ---------------- b6db2e80a9ce^ 0.103461 0.006303 0.035716 8eb2145ff0fb 0.192307 (x1.86) 0.012115 (x1.92) 0.052135 (x1.46) this patch 0.139986 (x1.35) 0.006389 (x1.01) 0.037176 (x1.04)

ancestor: rename local aliases of heapq functions in _lazyancestorsiter() The original names no longer look pretty. Just call them as heap*() instead.

ancestor: optimize _lazyancestorsiter() for contiguous chains If there's no revision between p1 and current, p1 must be the next revision to visit. In this case, we can get around the overhead of heappop/push operations. Note that this is faster than using heapreplace(). 'current - p1 == 1' could be generalized as 'all(r not in seen for r in xrange(p1, current)', but Python is too slow to do such thing.

ancestor: unroll loop of parents in _lazyancestorsiter() This change itself isn't major performance win, but it helps optimizing the visit loop for contiguous chains. See the next patch.

ancestor: return early from _lazyancestorsiter() when reached to stoprev There's no need to empty the heap.

ancestor: remove alias of initrevs from _lazyancestorsiter() It's just redundant and less comprehensible.