bisect: avoid copying ancestor list for non-merge commits During a bisection, hg needs to compute a list of all ancestors for every candidate commit. This is accomplished via a bottom-up traversal of the set of candidates, during which each revision's ancestor list is populated using the ancestor list of its parent(s). Previously, this involved copying the entire list, which could be very long in if the bisection range was large. To help improve this, we can observe that each candidate commit is visited exactly once, at which point its ancestor list is copied into its children's lists and then dropped. In the case of non-merge commits, a commit's ancestor list consists exactly of its parent's list plus itself. This means that we can trivially reuse the parent's existing list for one of its non-merge children, which avoids copying entirely if that commit is the parent's only child. This makes bisections over linear ranges of commits much faster. During some informal testing in the large publicly-available `mozilla-central` repository, this noticeably sped up bisections over large ranges of history: Setup: $ cd mozilla-central $ hg bisect --reset $ hg bisect --good 0 $ hg log -r tip -T '{rev}\n' 628417 Test: $ time hg bisect --bad tip --noupdate Before: real 3m35.927s user 3m35.553s sys 0m0.319s After: real 1m41.142s user 1m40.810s sys 0m0.285s

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#require execbit

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b51a8138292a introduced a regression where we would mention in the

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changelog executable files added by the second parent of a merge. Test

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that that doesn't happen anymore

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  $ hg init repo

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  $ cd repo

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  $ echo foo > foo

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  $ hg ci -qAm 'add foo'

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  $ echo bar > bar

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  $ chmod +x bar

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  $ hg ci -qAm 'add bar'

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manifest of p2:

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  $ hg manifest

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  bar

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  foo

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  $ hg up -qC 0

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  $ echo >> foo

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  $ hg ci -m 'change foo'

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  created new head

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manifest of p1:

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  $ hg manifest

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  foo

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  $ hg merge

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  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

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  (branch merge, don't forget to commit)

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  $ chmod +x foo

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  $ hg ci -m 'merge'

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this should not mention bar but should mention foo:

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  $ hg tip -v

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  changeset:   3:c53d17ff3380

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  tag:         tip

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  parent:      2:ed1b79f46b9a

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  parent:      1:d394a8db219b

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  user:        test

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  date:        Thu Jan 01 00:00:00 1970 +0000

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  files:       foo

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  description:

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  merge

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  $ hg debugindex bar

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     rev linkrev       nodeid    p1-nodeid    p2-nodeid

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       0       1 b004912a8510 000000000000 000000000000

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  $ cd ..