view tests/test-paths.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

  $ hg init a
  $ hg clone a b
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd a
  $ echo '[paths]' >> .hg/hgrc
  $ echo 'dupe = ../b' >> .hg/hgrc
  $ echo 'expand = $SOMETHING/bar' >> .hg/hgrc
  $ hg in dupe
  comparing with $TESTTMP/b (glob)
  no changes found
  [1]
  $ cd ..
  $ hg -R a in dupe
  comparing with $TESTTMP/b (glob)
  no changes found
  [1]
  $ cd a
  $ hg paths
  dupe = $TESTTMP/b (glob)
  expand = $TESTTMP/a/$SOMETHING/bar (glob)
  $ SOMETHING=foo hg paths
  dupe = $TESTTMP/b (glob)
  expand = $TESTTMP/a/foo/bar (glob)
#if msys
  $ SOMETHING=//foo hg paths
  dupe = $TESTTMP/b (glob)
  expand = /foo/bar
#else
  $ SOMETHING=/foo hg paths
  dupe = $TESTTMP/b (glob)
  expand = /foo/bar
#endif
  $ hg paths -q
  dupe
  expand
  $ hg paths dupe
  $TESTTMP/b (glob)
  $ hg paths -q dupe
  $ hg paths unknown
  not found!
  [1]
  $ hg paths -q unknown
  [1]
  $ cd ..

'file:' disables [paths] entries for clone destination

  $ cat >> $HGRCPATH <<EOF
  > [paths]
  > gpath1 = http://hg.example.com
  > EOF

  $ hg clone a gpath1
  abort: cannot create new http repository
  [255]

  $ hg clone a file:gpath1
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd gpath1
  $ hg -q id
  000000000000

  $ cd ..