Mercurial > hg
view tests/test-symlink-placeholder.t @ 18986:2f7186400a07
ancestor: a new algorithm that is faster for nodes near tip
Instead of walking all the way to the root of the DAG, we generate
a set of candidate GCA revs, then figure out which ones will win
the race to the root (usually without needing to traverse all the
way to the root).
In the common case of nodes that are close to each other in both
revision number and topology, this is usually a big win: it makes
"hg --time debugancestors" up to 9 times faster than the more general
ancestor function when measured on heads of the linux-2.6 hg repo.
Victory is not assured, however. The older function can still win
by a large margin if one node is much closer to the root than the
other, or by a much smaller amount if one is an ancestor of the
other.
For now, we've also got a small paranoid harness function that calls
both ancestor functions on every input and ensures that they give
equivalent answers.
Even without the checker function, the old ancestor function needs
to stay alive for the time being, as its generality is used by
context.filectx.merge.
author | Bryan O'Sullivan <bryano@fb.com> |
---|---|
date | Tue, 16 Apr 2013 10:08:18 -0700 |
parents | f2719b387380 |
children | 36f48c7d5944 |
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$ "$TESTDIR/hghave" symlink || exit 80 Create extension that can disable symlink support: $ cat > nolink.py <<EOF > from mercurial import extensions, util > def setflags(orig, f, l, x): > pass > def checklink(orig, path): > return False > def extsetup(ui): > extensions.wrapfunction(util, 'setflags', setflags) > extensions.wrapfunction(util, 'checklink', checklink) > EOF $ hg init unix-repo $ cd unix-repo $ echo foo > a $ ln -s a b $ hg ci -Am0 adding a adding b $ cd .. Simulate a checkout shared on NFS/Samba: $ hg clone -q unix-repo shared $ cd shared $ rm b $ echo foo > b $ hg --config extensions.n=$TESTTMP/nolink.py status --debug ignoring suspect symlink placeholder "b" Make a clone using placeholders: $ hg --config extensions.n=$TESTTMP/nolink.py clone . ../win-repo updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd ../win-repo $ cat b a (no-eol) $ hg --config extensions.n=$TESTTMP/nolink.py st --debug Write binary data to the placeholder: >>> open('b', 'w').write('this is a binary\0') $ hg --config extensions.n=$TESTTMP/nolink.py st --debug ignoring suspect symlink placeholder "b" Write a long string to the placeholder: >>> open('b', 'w').write('this' * 1000) $ hg --config extensions.n=$TESTTMP/nolink.py st --debug ignoring suspect symlink placeholder "b" Commit shouldn't succeed: $ hg --config extensions.n=$TESTTMP/nolink.py ci -m1 nothing changed [1] Write a valid string to the placeholder: >>> open('b', 'w').write('this') $ hg --config extensions.n=$TESTTMP/nolink.py st --debug M b $ hg --config extensions.n=$TESTTMP/nolink.py ci -m1 $ hg manifest tip --verbose 644 a 644 @ b $ cd ..