view tests/test-commit-unresolved.t @ 17970:0b03454abae7

ancestor: faster algorithm for difference of ancestor sets

One of the major reasons rebase is slow in large repositories is
the computation of the detach set: the set of ancestors of the
changesets to rebase not in the destination parent. This is currently
done via a revset that does two walks all the way to the root of
the DAG. Instead of doing that, to find ancestors of a set <revs>
not in another set <common> we walk up the tree in reverse revision
number order, maintaining sets of nodes visited from <revs>, <common>
or both.

For the common case where the sets are close both topologically and
in revision number (relative to repository size), this has been
found to speed up rebase by around 15-20%. When the nodes are farther
apart and the DAG is highly branching, it is harder to say which
would win.

Here's how long computing the detach set takes in a linear repository
with over 400000 changesets, rebasing near tip:

Rebasing across 4 changesets
Revset method: 2.2s
New algorithm: 0.00015s

Rebasing across 250 changesets
Revset method: 2.2s
New algorithm: 0.00069s

Rebasing across 10000 changesets
Revset method: 2.4s
New algorithm: 0.019s

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "graphlog=" >> $HGRCPATH

  $ addcommit () {
  >     echo $1 > $1
  >     hg add $1
  >     hg commit -d "${2} 0" -m $1
  > }

  $ commit () {
  >     hg commit -d "${2} 0" -m $1
  > }

  $ hg init a
  $ cd a
  $ addcommit "A" 0
  $ addcommit "B" 1
  $ echo "C" >> A
  $ commit "C" 2

  $ hg update -C 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo "D" >> A
  $ commit "D" 3
  created new head

Merging a conflict araises

  $ hg merge
  merging A
  warning: conflicts during merge.
  merging A incomplete! (edit conflicts, then use 'hg resolve --mark')
  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

Correct the conflict without marking the file as resolved

  $ echo "ABCD" > A
  $ hg commit -m "Merged"
  abort: unresolved merge conflicts (see hg help resolve)
  [255]

Mark the conflict as resolved and commit

  $ hg resolve -m A
  $ hg commit -m "Merged"

  $ cd ..