Mercurial > hg
view tests/test-merge-default.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
author | Siddharth Agarwal <sid0@fb.com> |
---|---|
date | Mon, 26 Nov 2012 11:46:51 -0800 |
parents | fc8c7a5ccc4a |
children | 94f77624dbb5 |
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$ hg init $ echo a > a $ hg commit -A -ma adding a $ echo b >> a $ hg commit -mb $ echo c >> a $ hg commit -mc $ hg up 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo d >> a $ hg commit -md created new head $ hg up 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo e >> a $ hg commit -me created new head $ hg up 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved Should fail because not at a head: $ hg merge abort: branch 'default' has 3 heads - please merge with an explicit rev (run 'hg heads .' to see heads) [255] $ hg up 1 files updated, 0 files merged, 0 files removed, 0 files unresolved Should fail because > 2 heads: $ HGMERGE=internal:other; export HGMERGE $ hg merge abort: branch 'default' has 3 heads - please merge with an explicit rev (run 'hg heads .' to see heads) [255] Should succeed: $ hg merge 2 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg commit -mm1 Should succeed - 2 heads: $ hg merge -P changeset: 3:ea9ff125ff88 parent: 1:1846eede8b68 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: d $ hg merge 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg commit -mm2 Should fail because at tip: $ hg merge abort: nothing to merge [255] $ hg up 0 1 files updated, 0 files merged, 0 files removed, 0 files unresolved Should fail because there is only one head: $ hg merge abort: nothing to merge (use 'hg update' instead) [255] $ hg up 3 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo f >> a $ hg branch foobranch marked working directory as branch foobranch (branches are permanent and global, did you want a bookmark?) $ hg commit -mf Should fail because merge with other branch: $ hg merge abort: branch 'foobranch' has one head - please merge with an explicit rev (run 'hg heads' to see all heads) [255] Test for issue2043: ensure that 'merge -P' shows ancestors of 6 that are not ancestors of 7, regardless of where their least common ancestor is. Merge preview not affected by common ancestor: $ hg up -q 7 $ hg merge -q -P 6 2:2d95304fed5d 4:f25cbe84d8b3 5:a431fabd6039 6:e88e33f3bf62