tests/test-hardlinks.t

branchcache: stop writing more branchcache file on disk than needed

Before this change, we were unconditionally writing a branchmap file for the
filter level passed to `update_disk`. This is actually counter productive if no
update were needed for this filter level. In many case, the branch cache for a
filter level is identical to its parent "subset" and it is better to simply
keep the subset update and reuse it every time instead of having to do identical
work for similar subset.

So we change the `update_disk` method to only write a file when that filter
level differ from its parent. This removes many cases where identical files were
written, requiring multiple boring update in the test suite.

The only notable changes is the change to `test-strip-branch-cache.t`, this
case was checking a scenario that no longer reproduce the bug as writing less
branchmap file result in less stalled cache on disk.

Strictly speaking, we could create a more convoluted scenario that create a
similar issue. However the next changeset would also cover that scenario so we
directly updated that test case to a "no longer buggy" state.

#require hardlink reporevlogstore

  $ cat > nlinks.py <<EOF
  > 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
  > 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-b870a51b.nd (rust !)
  1 r1/.hg/store/00changelog.d
  1 r1/.hg/store/00changelog.i
  1 r1/.hg/store/00changelog.n (rust !)
  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/requires
  1 r1/.hg/store/undo
  1 r1/.hg/store/undo.backup.00changelog.n.bck (rust !)
  1 r1/.hg/store/undo.backup.fncache.bck (repofncache !)
  1 r1/.hg/store/undo.backupfiles


Create hardlinked clone r2:

  $ hg clone -U --debug r1 r2 --config progress.debug=true
  linking: 1/8 files (12.50%) (no-rust !)
  linking: 2/8 files (25.00%) (no-rust !)
  linking: 3/8 files (37.50%) (no-rust !)
  linking: 4/8 files (50.00%) (no-rust !)
  linking: 5/8 files (62.50%) (no-rust !)
  linking: 6/8 files (75.00%) (no-rust !)
  linking: 7/8 files (87.50%) (no-rust !)
  linking: 8/8 files (100.00%) (no-rust !)
  linked 8 files (no-rust !)
  linking: 1/10 files (10.00%) (rust !)
  linking: 2/10 files (20.00%) (rust !)
  linking: 3/10 files (30.00%) (rust !)
  linking: 4/10 files (40.00%) (rust !)
  linking: 5/10 files (50.00%) (rust !)
  linking: 6/10 files (60.00%) (rust !)
  linking: 7/10 files (70.00%) (rust !)
  linking: 8/10 files (80.00%) (rust !)
  linking: 9/10 files (90.00%) (rust !)
  linking: 10/10 files (100.00%) (rust !)
  linked 10 files (rust !)
  updating the branch cache

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
  1 r1/.hg/store/00changelog-b870a51b.nd (rust !)
  2 r1/.hg/store/00changelog.d
  2 r1/.hg/store/00changelog.i
  1 r1/.hg/store/00changelog.n (rust !)
  2 r1/.hg/store/00manifest.i
  2 r1/.hg/store/data/d1/f2.i
  2 r1/.hg/store/data/f1.i
  1 r1/.hg/store/fncache (repofncache !)
  1 r1/.hg/store/phaseroots
  1 r1/.hg/store/requires
  1 r1/.hg/store/undo
  1 r1/.hg/store/undo.backup.00changelog.n.bck (rust !)
  1 r1/.hg/store/undo.backup.fncache.bck (repofncache !)
  1 r1/.hg/store/undo.backupfiles

  $ nlinksdir r2/.hg/store
  1 r2/.hg/store/00changelog-b870a51b.nd (rust !)
  2 r2/.hg/store/00changelog.d
  2 r2/.hg/store/00changelog.i
  1 r2/.hg/store/00changelog.n (rust !)
  2 r2/.hg/store/00manifest.i
  2 r2/.hg/store/data/d1/f2.i
  2 r2/.hg/store/data/f1.i
  1 r2/.hg/store/fncache (repofncache !)
  1 r2/.hg/store/requires

Repo r3 should not be hardlinked:

  $ nlinksdir r3/.hg/store
  1 r3/.hg/store/00changelog-88698448.nd (rust !)
  1 r3/.hg/store/00changelog.d
  1 r3/.hg/store/00changelog.i
  1 r3/.hg/store/00changelog.n (rust !)
  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/requires
  1 r3/.hg/store/undo
  1 r3/.hg/store/undo.backupfiles


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-ea337809.nd (rust !)
  1 r3/.hg/store/00changelog.d
  1 r3/.hg/store/00changelog.i
  1 r3/.hg/store/00changelog.n (rust !)
  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/requires
  1 r3/.hg/store/undo
  1 r3/.hg/store/undo.backup.00changelog.n.bck (rust !)
  1 r3/.hg/store/undo.backupfiles

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

  $ hg -R r2 verify -q

  $ 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-b870a51b.nd (rust !)
  1 r2/.hg/store/00changelog.d
  1 r2/.hg/store/00changelog.i
  1 r2/.hg/store/00changelog.n (rust !)
  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 !)
  1 r2/.hg/store/requires

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

  $ hg -R r2 verify -q

  $ 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-b870a51b.nd (rust !)
  1 r2/.hg/store/00changelog.d
  1 r2/.hg/store/00changelog.i
  1 r2/.hg/store/00changelog.n (rust !)
  1 r2/.hg/store/00manifest.i
  1 r2/.hg/store/data/d1/f2.i
  1 r2/.hg/store/data/f1.i
  1 r2/.hg/store/fncache (repofncache !)
  1 r2/.hg/store/requires

#if hardlink-whitelisted repofncache
  $ nlinksdir r2/.hg/store/fncache
  1 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
  [24] r4/.hg/branch (re)
  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/cache/tags2
  2 r4/.hg/cache/tags2-served
  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-7f2eb713.nd (rust !)
  2 r4/.hg/store/00changelog.d
  2 r4/.hg/store/00changelog.i
  2 r4/.hg/store/00changelog.n (rust !)
  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/requires
  2 r4/.hg/store/undo
  2 r4/.hg/store/undo.backup.00changelog.n.bck (rust !)
  2 r4/.hg/store/undo.backupfiles
  [24] r4/.hg/undo.backup.branch.bck (re)
  2 r4/\.hg/undo\.backup\.dirstate.bck (re)
  2 r4/.hg/undo.desc
  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.bck r4/.hg/dirstate
  2 r4/.hg/dirstate
  2 r4/.hg/undo.backup.dirstate.bck
#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
  2 r4/.hg/cache/tags2
  2 r4/.hg/cache/tags2-served
  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-7f2eb713.nd (rust !)
  2 r4/.hg/store/00changelog.d
  2 r4/.hg/store/00changelog.i
  2 r4/.hg/store/00changelog.n (rust !)
  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/requires
  2 r4/.hg/store/undo
  2 r4/.hg/store/undo.backup.00changelog.n.bck (rust !)
  2 r4/.hg/store/undo.backupfiles
  [23] r4/.hg/undo.backup.branch.bck (re)
  2 r4/\.hg/undo\.backup\.dirstate.bck (re)
  2 r4/.hg/undo.desc
  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.bck r4/.hg/dirstate
  1 r4/.hg/dirstate
  2 r4/.hg/undo.backup.dirstate.bck
#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 ..