py3: make catapult usable from the test runner in py3 Differential Revision: https://phab.mercurial-scm.org/D6577

py3: use integer division for the value passed to xrange Differential Revision: https://phab.mercurial-scm.org/D6576

pycompat: make fewer assumptions about sys.executable There are many Python "bundlers" which create an archive to run a Python binary from, and they may not set sys.executable at all - handle that case properly, especially to run tests. Differential Revision: https://phab.mercurial-scm.org/D6575

update: fix spurious unclean status bug shown by previous commit The crux of the problem is: - the dirstate is corrupted (the sizes/dates are assigned to the wrong files) - because when worker.worker is used with a return value (batchget in merge.py here), the return value when worker.worker effectively parallelizes is permuted - this is because worker.worker's partition of input and combination of output values are not inverses of one another: it split [1,2,3,4,5,6] into [[1,3,5],[2,4,6]], but combines that into [1,3,5,2,4,6]. Given that worker.worker doesn't call its function argument on contiguous chunks on the input arguments, sticking with lists means we'd need to know the relation between the inputs of worker.worker function argument (for instance, requiring that every input element is mapped to exactly one output element). It seems better to instead switch return values to dicts, which can combined reliably with a straighforward restriction. Differential Revision: https://phab.mercurial-scm.org/D6581

tests: show bug in update introduced in 87a34c767384 As reported by Martin at https://phab.mercurial-scm.org/D6475. Differential Revision: https://phab.mercurial-scm.org/D6580

copies: document how 'copies' dict instances are reused We avoid copying these instances as much as we can, so it's not obvious what's safe to do with them. This patch tries to explain what is safe and what is not. Differential Revision: https://phab.mercurial-scm.org/D6578

copies: simplify merging of copy dicts on merge commits After we removed some filtering in 35d674a3d5db (copies: don't filter out copy targets created on other side of merge commit, 2019-04-18), we will always include all entries from "copies1", so we can simplify the code based on that. Differential Revision: https://phab.mercurial-scm.org/D6561

copies: remove a redundant matcher filtering in _changesetforwardcopies() We filter before pushing items on the queue, so we don't need to filter after popping. Differential Revision: https://phab.mercurial-scm.org/D6560