obsolete: order of magnitude speedup in _computebumpedset
Reminder: a changeset is said "bumped" if it tries to obsolete a immutable
changeset.
The previous algorithm for computing bumped changeset was:
1) Get all public changesets
2) Find all they successors
3) Search for stuff that are eligible for being "bumped"
(mutable and non obsolete)
The entry size of this algorithm is `O(len(public))` which is mostly the same as
`O(len(repo))`. Even this this approach mean fewer obsolescence marker are
traveled, this is not very scalable.
The new algorithm is:
1) For each potential bumped changesets (non obsolete mutable)
2) iterate over precursors
3) if a precursors is public. changeset is bumped
We travel more obsolescence marker, but the entry size is much smaller since
the amount of potential bumped should remains mostly stable with time `O(1)`.
On some confidential gigantic repo this move bumped computation from 15.19s to
0.46s (×33 speedup…). On "smaller" repo (mercurial, cubicweb's review) no
significant gain were seen. The additional traversal of obsolescence marker is
probably probably counter balance the advantage of it.
Other optimisation could be done in the future (eg: sharing precursors cache
for divergence detection)
$ hg init
audit of .hg
$ hg add .hg/00changelog.i
abort: path contains illegal component: .hg/00changelog.i (glob)
[255]
#if symlink
Symlinks
$ mkdir a
$ echo a > a/a
$ hg ci -Ama
adding a/a
$ ln -s a b
$ echo b > a/b
$ hg add b/b
abort: path 'b/b' traverses symbolic link 'b' (glob)
[255]
$ hg add b
should still fail - maybe
$ hg add b/b
abort: path 'b/b' traverses symbolic link 'b' (glob)
[255]
#endif
unbundle tampered bundle
$ hg init target
$ cd target
$ hg unbundle "$TESTDIR/bundles/tampered.hg"
adding changesets
adding manifests
adding file changes
added 5 changesets with 6 changes to 6 files (+4 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
attack .hg/test
$ hg manifest -r0
.hg/test
$ hg update -Cr0
abort: path contains illegal component: .hg/test (glob)
[255]
attack foo/.hg/test
$ hg manifest -r1
foo/.hg/test
$ hg update -Cr1
abort: path 'foo/.hg/test' is inside nested repo 'foo' (glob)
[255]
attack back/test where back symlinks to ..
$ hg manifest -r2
back
back/test
#if symlink
$ hg update -Cr2
abort: path 'back/test' traverses symbolic link 'back'
[255]
#else
('back' will be a file and cause some other system specific error)
$ hg update -Cr2
abort: * (glob)
[255]
#endif
attack ../test
$ hg manifest -r3
../test
$ hg update -Cr3
abort: path contains illegal component: ../test (glob)
[255]
attack /tmp/test
$ hg manifest -r4
/tmp/test
$ hg update -Cr4
abort: path contains illegal component: /tmp/test (glob)
[255]
$ cd ..