view tests/test-hardlinks.t @ 42621:99ebde4fec99

commit: improve the files field of changelog for merges

Currently, the files list of merge commits repeats all the deletions
(either actual deletions, or files that got renamed) that happened
between base and p2 of the merge. If p2 is the main branch, the list
can easily be much bigger than the change being merged.

This results in various problems worth improving:
- changelog is bigger than necessary
- `hg log directory` lists many unrelated merge commits, and `hg log
  -v -r commit` frequently fills multiple screens worth of files
- it possibly slows down adjustlinkrev, by forcing it to read more
  manifests, and that function can certainly be a bottleneck
- the server side of pulls can waste a lot of time simply opening the
  filelogs for pointless files (the constant factors for opening even
  a tiny filelog is apparently pretty bad)

So stop listing such files as described in the code.  Impacted merge
commits and their descendants get a different hash than they would
have without this. This doesn't seem problematic, except for
convert. The previous commit helped with that in the hg->hg case (but
if you do svn->hg twice from scratch, hashes can still change).

The rest of the description is numbers. I don't have much to report,
because recreating the files list of existing repositories is not
easy:
- debugupgradeformat and bundle/unbundle don't recreate the list
- export/import tends to choke quickly applying patches or on
  description that contain diffs,
- merge commits from the convert extension don't have the right files
  list for reasons orthogonal to the current commit
- replaying the merge with hg update/hg merge/hg revert --all/hg
  commit can end up failing in hg revert
- I wasn't sure that using debugsetparents + debugrebuilddirstate
  would really build the right thing

I measured commit time before and after this change, in a case with no
files filtered out, several files filtered out (no difference) and 5k
files filtered out (+1% time).

Recreating the 100 more recent merges in a private repo, the
concatenated uncompressed files lists goes from 1.12MB to
0.52MB. Excluding 3 merges that are not representative, then the size
goes from 570k to 15k.
I converted part of mozilla-central, and observed file list shrinking
quite a bit too, starting at the very first merge, 733641d9feaf, going
from 550 files to 10 files (although they have relatively few merges,
so they probably wouldn't care).

Differential Revision: https://phab.mercurial-scm.org/D6613

#require hardlink reporevlogstore

  $ cat > nlinks.py <<EOF
  > from __future__ import print_function
  > import sys
  > from mercurial import pycompat, util
  > for f in sorted(sys.stdin.readlines()):
  >     f = f[:-1]
  >     print(util.nlinks(pycompat.fsencode(f)), f)
  > EOF

  $ nlinksdir()
  > {
  >     find "$@" -type f | "$PYTHON" $TESTTMP/nlinks.py
  > }

Some implementations of cp can't create hardlinks (replaces 'cp -al' on Linux):

  $ cat > linkcp.py <<EOF
  > from __future__ import absolute_import
  > import sys
  > from mercurial import pycompat, util
  > util.copyfiles(pycompat.fsencode(sys.argv[1]),
  >                pycompat.fsencode(sys.argv[2]), hardlink=True)
  > EOF

  $ linkcp()
  > {
  >     "$PYTHON" $TESTTMP/linkcp.py $1 $2
  > }

Prepare repo r1:

  $ hg init r1
  $ cd r1

  $ echo c1 > f1
  $ hg add f1
  $ hg ci -m0

  $ mkdir d1
  $ cd d1
  $ echo c2 > f2
  $ hg add f2
  $ hg ci -m1
  $ cd ../..

  $ nlinksdir r1/.hg/store
  1 r1/.hg/store/00changelog.i
  1 r1/.hg/store/00manifest.i
  1 r1/.hg/store/data/d1/f2.i
  1 r1/.hg/store/data/f1.i
  1 r1/.hg/store/fncache (repofncache !)
  1 r1/.hg/store/phaseroots
  1 r1/.hg/store/undo
  1 r1/.hg/store/undo.backup.fncache (repofncache !)
  1 r1/.hg/store/undo.backupfiles
  1 r1/.hg/store/undo.phaseroots


Create hardlinked clone r2:

  $ hg clone -U --debug r1 r2 --config progress.debug=true
  linking: 1 files
  linking: 2 files
  linking: 3 files
  linking: 4 files
  linking: 5 files
  linking: 6 files
  linking: 7 files
  linked 7 files

Create non-hardlinked clone r3:

  $ hg clone --pull r1 r3
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  new changesets 40d85e9847f2:7069c422939c
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved


Repos r1 and r2 should now contain hardlinked files:

  $ nlinksdir r1/.hg/store
  2 r1/.hg/store/00changelog.i
  2 r1/.hg/store/00manifest.i
  2 r1/.hg/store/data/d1/f2.i
  2 r1/.hg/store/data/f1.i
  2 r1/.hg/store/fncache (repofncache !)
  1 r1/.hg/store/phaseroots
  1 r1/.hg/store/undo
  1 r1/.hg/store/undo.backup.fncache (repofncache !)
  1 r1/.hg/store/undo.backupfiles
  1 r1/.hg/store/undo.phaseroots

  $ nlinksdir r2/.hg/store
  2 r2/.hg/store/00changelog.i
  2 r2/.hg/store/00manifest.i
  2 r2/.hg/store/data/d1/f2.i
  2 r2/.hg/store/data/f1.i
  2 r2/.hg/store/fncache (repofncache !)

Repo r3 should not be hardlinked:

  $ nlinksdir r3/.hg/store
  1 r3/.hg/store/00changelog.i
  1 r3/.hg/store/00manifest.i
  1 r3/.hg/store/data/d1/f2.i
  1 r3/.hg/store/data/f1.i
  1 r3/.hg/store/fncache (repofncache !)
  1 r3/.hg/store/phaseroots
  1 r3/.hg/store/undo
  1 r3/.hg/store/undo.backupfiles
  1 r3/.hg/store/undo.phaseroots


Create a non-inlined filelog in r3:

  $ cd r3/d1
  >>> f = open('data1', 'wb')
  >>> for x in range(10000):
  ...     f.write(b"%d\n" % x) and None
  >>> f.close()
  $ for j in 0 1 2 3 4 5 6 7 8 9; do
  >   cat data1 >> f2
  >   hg commit -m$j
  > done
  $ cd ../..

  $ nlinksdir r3/.hg/store
  1 r3/.hg/store/00changelog.i
  1 r3/.hg/store/00manifest.i
  1 r3/.hg/store/data/d1/f2.d
  1 r3/.hg/store/data/d1/f2.i
  1 r3/.hg/store/data/f1.i
  1 r3/.hg/store/fncache (repofncache !)
  1 r3/.hg/store/phaseroots
  1 r3/.hg/store/undo
  1 r3/.hg/store/undo.backup.fncache (repofncache !)
  1 r3/.hg/store/undo.backup.phaseroots
  1 r3/.hg/store/undo.backupfiles
  1 r3/.hg/store/undo.phaseroots

Push to repo r1 should break up most hardlinks in r2:

  $ hg -R r2 verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 2 changes to 2 files

  $ cd r3
  $ hg push
  pushing to $TESTTMP/r1
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 10 changesets with 10 changes to 1 files

  $ cd ..

  $ nlinksdir r2/.hg/store
  1 r2/.hg/store/00changelog.i
  1 r2/.hg/store/00manifest.i
  1 r2/.hg/store/data/d1/f2.i
  2 r2/.hg/store/data/f1.i
  [12] r2/\.hg/store/fncache (re) (repofncache !)

#if hardlink-whitelisted repofncache
  $ nlinksdir r2/.hg/store/fncache
  2 r2/.hg/store/fncache
#endif

  $ hg -R r2 verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 2 changes to 2 files


  $ cd r1
  $ hg up
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Committing a change to f1 in r1 must break up hardlink f1.i in r2:

  $ echo c1c1 >> f1
  $ hg ci -m00
  $ cd ..

  $ nlinksdir r2/.hg/store
  1 r2/.hg/store/00changelog.i
  1 r2/.hg/store/00manifest.i
  1 r2/.hg/store/data/d1/f2.i
  1 r2/.hg/store/data/f1.i
  [12] r2/\.hg/store/fncache (re) (repofncache !)

#if hardlink-whitelisted repofncache
  $ nlinksdir r2/.hg/store/fncache
  2 r2/.hg/store/fncache
#endif

Create a file which exec permissions we will change
  $ cd r3
  $ echo "echo hello world" > f3
  $ hg add f3
  $ hg ci -mf3
  $ cd ..

  $ cd r3
  $ hg tip --template '{rev}:{node|short}\n'
  12:d3b77733a28a
  $ echo bla > f1
  $ chmod +x f3
  $ hg ci -m1
  $ cd ..

Create hardlinked copy r4 of r3 (on Linux, we would call 'cp -al'):

  $ linkcp r3 r4

'checklink' is produced by hardlinking a symlink, which is undefined whether
the symlink should be followed or not. It does behave differently on Linux and
BSD. Just remove it so the test pass on both platforms.

  $ rm -f r4/.hg/wcache/checklink

r4 has hardlinks in the working dir (not just inside .hg):

  $ nlinksdir r4
  2 r4/.hg/00changelog.i
  2 r4/.hg/branch
  2 r4/.hg/cache/branch2-base
  2 r4/.hg/cache/branch2-served
  2 r4/.hg/cache/rbc-names-v1
  2 r4/.hg/cache/rbc-revs-v1
  2 r4/.hg/dirstate
  2 r4/.hg/fsmonitor.state (fsmonitor !)
  2 r4/.hg/hgrc
  2 r4/.hg/last-message.txt
  2 r4/.hg/requires
  2 r4/.hg/store/00changelog.i
  2 r4/.hg/store/00manifest.i
  2 r4/.hg/store/data/d1/f2.d
  2 r4/.hg/store/data/d1/f2.i
  2 r4/.hg/store/data/f1.i
  2 r4/.hg/store/data/f3.i
  2 r4/.hg/store/fncache (repofncache !)
  2 r4/.hg/store/phaseroots
  2 r4/.hg/store/undo
  2 r4/.hg/store/undo.backup.fncache (repofncache !)
  2 r4/.hg/store/undo.backup.phaseroots
  2 r4/.hg/store/undo.backupfiles
  2 r4/.hg/store/undo.phaseroots
  [24] r4/\.hg/undo\.backup\.dirstate (re)
  2 r4/.hg/undo.bookmarks
  2 r4/.hg/undo.branch
  2 r4/.hg/undo.desc
  [24] r4/\.hg/undo\.dirstate (re)
  2 r4/.hg/wcache/checkisexec (execbit !)
  2 r4/.hg/wcache/checklink-target (symlink !)
  2 r4/.hg/wcache/checknoexec (execbit !)
  2 r4/.hg/wcache/manifestfulltextcache (reporevlogstore !)
  2 r4/d1/data1
  2 r4/d1/f2
  2 r4/f1
  2 r4/f3

Update back to revision 12 in r4 should break hardlink of file f1 and f3:
#if hardlink-whitelisted
  $ nlinksdir r4/.hg/undo.backup.dirstate r4/.hg/undo.dirstate
  4 r4/.hg/undo.backup.dirstate
  4 r4/.hg/undo.dirstate
#endif


  $ hg -R r4 up 12
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved (execbit !)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved (no-execbit !)

  $ nlinksdir r4
  2 r4/.hg/00changelog.i
  1 r4/.hg/branch
  2 r4/.hg/cache/branch2-base
  2 r4/.hg/cache/branch2-served
  2 r4/.hg/cache/rbc-names-v1
  2 r4/.hg/cache/rbc-revs-v1
  1 r4/.hg/dirstate
  1 r4/.hg/fsmonitor.state (fsmonitor !)
  2 r4/.hg/hgrc
  2 r4/.hg/last-message.txt
  2 r4/.hg/requires
  2 r4/.hg/store/00changelog.i
  2 r4/.hg/store/00manifest.i
  2 r4/.hg/store/data/d1/f2.d
  2 r4/.hg/store/data/d1/f2.i
  2 r4/.hg/store/data/f1.i
  2 r4/.hg/store/data/f3.i
  2 r4/.hg/store/fncache
  2 r4/.hg/store/phaseroots
  2 r4/.hg/store/undo
  2 r4/.hg/store/undo.backup.fncache (repofncache !)
  2 r4/.hg/store/undo.backup.phaseroots
  2 r4/.hg/store/undo.backupfiles
  2 r4/.hg/store/undo.phaseroots
  [24] r4/\.hg/undo\.backup\.dirstate (re)
  2 r4/.hg/undo.bookmarks
  2 r4/.hg/undo.branch
  2 r4/.hg/undo.desc
  [24] r4/\.hg/undo\.dirstate (re)
  2 r4/.hg/wcache/checkisexec (execbit !)
  2 r4/.hg/wcache/checklink-target (symlink !)
  2 r4/.hg/wcache/checknoexec (execbit !)
  1 r4/.hg/wcache/manifestfulltextcache (reporevlogstore !)
  2 r4/d1/data1
  2 r4/d1/f2
  1 r4/f1
  1 r4/f3 (execbit !)
  2 r4/f3 (no-execbit !)

#if hardlink-whitelisted
  $ nlinksdir r4/.hg/undo.backup.dirstate r4/.hg/undo.dirstate
  4 r4/.hg/undo.backup.dirstate
  4 r4/.hg/undo.dirstate
#endif

Test hardlinking outside hg:

  $ mkdir x
  $ echo foo > x/a

  $ linkcp x y
  $ echo bar >> y/a

No diff if hardlink:

  $ diff x/a y/a

Test mq hardlinking:

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init a
  $ cd a

  $ hg qimport -n foo - << EOF
  > # HG changeset patch
  > # Date 1 0
  > diff -r 2588a8b53d66 a
  > --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  > +++ b/a	Wed Jul 23 15:54:29 2008 +0200
  > @@ -0,0 +1,1 @@
  > +a
  > EOF
  adding foo to series file

  $ hg qpush
  applying foo
  now at: foo

  $ cd ..
  $ linkcp a b
  $ cd b

  $ hg qimport -n bar - << EOF
  > # HG changeset patch
  > # Date 2 0
  > diff -r 2588a8b53d66 a
  > --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  > +++ b/b	Wed Jul 23 15:54:29 2008 +0200
  > @@ -0,0 +1,1 @@
  > +b
  > EOF
  adding bar to series file

  $ hg qpush
  applying bar
  now at: bar

  $ cat .hg/patches/status
  430ed4828a74fa4047bc816a25500f7472ab4bfe:foo
  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c:bar

  $ cat .hg/patches/series
  foo
  bar

  $ cat ../a/.hg/patches/status
  430ed4828a74fa4047bc816a25500f7472ab4bfe:foo

  $ cat ../a/.hg/patches/series
  foo

Test tags hardlinking:

  $ hg qdel -r qbase:qtip
  patch foo finalized without changeset message
  patch bar finalized without changeset message

  $ hg tag -l lfoo
  $ hg tag foo

  $ cd ..
  $ linkcp b c
  $ cd c

  $ hg tag -l -r 0 lbar
  $ hg tag -r 0 bar

  $ cat .hgtags
  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c foo
  430ed4828a74fa4047bc816a25500f7472ab4bfe bar

  $ cat .hg/localtags
  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c lfoo
  430ed4828a74fa4047bc816a25500f7472ab4bfe lbar

  $ cat ../b/.hgtags
  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c foo

  $ cat ../b/.hg/localtags
  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c lfoo

  $ cd ..