store: implement fncache basic path encoding in C
(This is not yet enabled; it will be turned on in a followup patch.)
The path encoding performed by fncache is complex and (perhaps
surprisingly) slow enough to negatively affect the overall performance
of Mercurial.
For a short path (< 120 bytes), the Python code can be reduced to a fairly
tractable state machine that either determines that nothing needs to be
done in a single pass, or performs the encoding in a second pass.
For longer paths, we avoid the more complicated hashed encoding scheme
for now, and fall back to Python.
Raw performance: I measured in a repo containing 150,000 files in its tip
manifest, with a median path name length of 57 bytes, and 95th percentile
of 96 bytes.
In this repo, the Python code takes 3.1 seconds to encode all path
names, while the hybrid C-and-Python code (called from Python) takes
0.21 seconds, for a speedup of about 14.
Across several other large repositories, I've measured the speedup from
the C code at between 26x and 40x.
For path names above 120 bytes where we must fall back to Python for
hashed encoding, the speedup is about 1.7x. Thus absolute performance
will depend strongly on the characteristics of a particular repository.
Check that obsolete properly strip heads
$ cat > obs.py << EOF
> import mercurial.obsolete
> mercurial.obsolete._enabled = True
> EOF
$ cat >> $HGRCPATH << EOF
> [phases]
> # public changeset are not obsolete
> publish=false
> [ui]
> logtemplate='{node|short} ({phase}) {desc|firstline}\n'
> [extensions]
> graphlog=
> EOF
$ echo "obs=${TESTTMP}/obs.py" >> $HGRCPATH
$ mkcommit() {
> echo "$1" > "$1"
> hg add "$1"
> hg ci -m "add $1"
> }
$ getid() {
> hg id --debug -ir "desc('$1')"
> }
$ hg init remote
$ cd remote
$ mkcommit base
$ hg phase --public .
$ cd ..
$ cp -r remote base
$ hg clone remote local
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd local
New head replaces old head
==========================
setup
$ mkcommit old
$ hg push
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
$ hg up -q '.^'
$ mkcommit new
created new head
$ hg debugobsolete `getid old` `getid new`
$ hg glog --hidden
@ 71e3228bffe1 (draft) add new
|
| x c70b08862e08 (draft) add old
|/
o b4952fcf48cf (public) add base
$ cp -r ../remote ../backup1
old exists remotely as draft. It is obsoleted by new that we now push.
Push should not warn about creating new head
$ hg push
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
old head is now public (public local version)
=============================================
setup
$ rm -fr ../remote
$ cp -r ../backup1 ../remote
$ hg -R ../remote phase --public c70b08862e08
$ hg pull -v
pulling from $TESTTMP/remote (glob)
searching for changes
no changes found
$ hg glog --hidden
@ 71e3228bffe1 (draft) add new
|
| o c70b08862e08 (public) add old
|/
o b4952fcf48cf (public) add base
Abort: old will still be an head because it's public.
$ hg push
pushing to $TESTTMP/remote (glob)
searching for changes
abort: push creates new remote head 71e3228bffe1!
(did you forget to merge? use push -f to force)
[255]
old head is now public (public remote version)
==============================================
TODO: Not implemented yet.
# setup
#
# $ rm -fr ../remote
# $ cp -r ../backup1 ../remote
# $ hg -R ../remote phase --public c70b08862e08
# $ hg phase --draft --force c70b08862e08
# $ hg glog --hidden
# @ 71e3228bffe1 (draft) add new
# |
# | x c70b08862e08 (draft) add old
# |/
# o b4952fcf48cf (public) add base
#
#
#
# Abort: old will still be an head because it's public.
#
# $ hg push
# pushing to $TESTTMP/remote
# searching for changes
# abort: push creates new remote head 71e3228bffe1!
# (did you forget to merge? use push -f to force)
# [255]
old head is obsolete but replacement is not pushed
==================================================
setup
$ rm -fr ../remote
$ cp -r ../backup1 ../remote
$ hg phase --draft --force '(0::) - 0'
$ hg up -q '.^'
$ mkcommit other
created new head
$ hg glog --hidden
@ d7d41ccbd4de (draft) add other
|
| o 71e3228bffe1 (draft) add new
|/
| x c70b08862e08 (draft) add old
|/
o b4952fcf48cf (public) add base
old exists remotely as draft. It is obsoleted by new but we don't push new.
Push should abort on new head
$ hg push -r 'desc("other")'
pushing to $TESTTMP/remote (glob)
searching for changes
abort: push creates new remote head d7d41ccbd4de!
(did you forget to merge? use push -f to force)
[255]
Both precursors and successors are already know remotely. Descendant adds heads
===============================================================================
setup. (The obsolete marker is known locally only
$ cd ..
$ rm -rf local
$ hg clone remote local
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd local
$ mkcommit old
old already tracked!
nothing changed
[1]
$ hg up -q '.^'
$ mkcommit new
created new head
$ hg push -f
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
$ mkcommit desc1
$ hg up -q '.^'
$ mkcommit desc2
created new head
$ hg debugobsolete `getid old` `getid new`
$ hg glog --hidden
@ 5fe37041cc2b (draft) add desc2
|
| o a3ef1d111c5f (draft) add desc1
|/
o 71e3228bffe1 (draft) add new
|
| x c70b08862e08 (draft) add old
|/
o b4952fcf48cf (public) add base
$ hg glog --hidden -R ../remote
o 71e3228bffe1 (draft) add new
|
| o c70b08862e08 (draft) add old
|/
@ b4952fcf48cf (public) add base
$ cp -r ../remote ../backup2
Push should not warn about adding new heads. We create one, but we'll delete
one anyway.
$ hg push
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files (+1 heads)
Remote head is unknown but obsoleted by a local changeset
=========================================================
setup
$ rm -fr ../remote
$ cp -r ../backup1 ../remote
$ cd ..
$ rm -rf local
$ hg clone remote local -r 0
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd local
$ mkcommit new
$ hg -R ../remote id --debug -r tip
c70b08862e0838ea6d7c59c85da2f1ed6c8d67da tip
$ hg id --debug -r tip
71e3228bffe1886550777233d6c97bb5a6b2a650 tip
$ hg debugobsolete c70b08862e0838ea6d7c59c85da2f1ed6c8d67da 71e3228bffe1886550777233d6c97bb5a6b2a650
$ hg glog --hidden
@ 71e3228bffe1 (draft) add new
|
o b4952fcf48cf (public) add base
$ hg glog --hidden -R ../remote
o c70b08862e08 (draft) add old
|
@ b4952fcf48cf (public) add base
Push should not complain about new heads.
It should not complain about "unsynced remote changes!" either but that's not
handled yet.
$ hg push --traceback
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)