Mercurial > hg
view tests/test-hardlinks.t @ 25757:4d1382fd96ff
context: write dirstate out explicitly at the end of markcommitted
To detect change of a file without redundant comparison of file
content, dirstate recognizes a file as certainly clean, if:
(1) it is already known as "normal",
(2) dirstate entry for it has valid (= not "-1") timestamp, and
(3) mode, size and timestamp of it on the filesystem are as same as
ones expected in dirstate
This works as expected in many cases, but doesn't in the corner case
that changing a file keeps mode, size and timestamp of it on the
filesystem.
The timetable below shows steps in one of typical such situations:
---- ----------------------------------- ----------------
timestamp of "f"
----------------
dirstate file-
time action mem file system
---- ----------------------------------- ---- ----- -----
* *** ***
- 'hg transplant REV1 REV2 ...'
- transplanting REV1
....
N
- change "f", but keep size N
(via 'patch.patch()')
- 'dirstate.normal("f")' N ***
(via 'repo.commit()')
- transplanting REV2
- change "f", but keep size N
(via 'patch.patch()')
- aborted while patching
N+1
- release wlock
- 'dirstate.write()' N N N
- 'hg status' shows "r1" as "clean" N N N
---- ----------------------------------- ---- ----- -----
The most important point is that 'dirstate.write()' is executed at N+1
or later. This causes writing dirstate timestamp N of "f" out
successfully. If it is executed at N, 'parsers.pack_dirstate()'
replaces timestamp N with "-1" before actual writing dirstate out.
This issue can occur when 'hg transplant' satisfies conditions below:
- multiple revisions to be transplanted change the same file
- those revisions don't change mode and size of the file, and
- the 2nd or later revision of them fails after changing the file
The root cause of this issue is that files are changed without
flushing in-memory dirstate changes via 'repo.commit()' (even though
omitting 'dirstate.normallookup()' on files changed by 'patch.patch()'
for efficiency also causes this issue).
To detect changes of files correctly, this patch writes in-memory
dirstate changes out explicitly after marking files as clean in
'committablectx.markcommitted()', which is invoked via
'repo.commit()'.
After this change, timetable is changed as below:
---- ----------------------------------- ----------------
timestamp of "f"
----------------
dirstate file-
time action mem file system
---- ----------------------------------- ---- ----- -----
* *** ***
- 'hg transplant REV1 REV2 ...'
- transplanting REV1
....
N
- change "f", but keep size N
(via 'patch.patch()')
- 'dirstate.normal("f")' N ***
(via 'repo.commit()')
----------------------------------- ---- ----- -----
- 'dirsttate.write()' -1 -1
----------------------------------- ---- ----- -----
- transplanting REV2
- change "f", but keep size N
(via 'patch.patch()')
- aborted while patching
N+1
- release wlock
- 'dirstate.write()' -1 -1 N
- 'hg status' shows "r1" as "clean" -1 -1 N
---- ----------------------------------- ---- ----- -----
To reproduce this issue in tests certainly, this patch emulates some
timing critical actions as below:
- change "f" at N
'patch.patch()' with 'fakepatchtime.py' explicitly changes mtime
of patched files to "2000-01-01 00:00" (= N).
- 'dirstate.write()' via 'repo.commit()' at N
'fakedirstatewritetime.py' forces 'pack_dirstate()' to use
"2000-01-01 00:00" as "now", only if 'pack_dirstate()' is invoked
via 'committablectx.markcommitted()'.
- 'dirstate.write()' via releasing wlock at N+1 (or "not at N")
'pack_dirstate()' via releasing wlock uses actual timestamp at
runtime as "now", and it should be different from the "2000-01-01
00:00" of "f".
BTW, this patch doesn't test cases below, even though 'patch.patch()'
is used similarly in these cases:
1. failure of 'hg import' or 'hg qpush'
2. success of 'hg import', 'hg qpush' or 'hg transplant'
Case (1) above doesn't cause this kind of issue, because:
- if patching is aborted by conflicts, changed files are committed
changed files are marked as CLEAN, even though they are partially
patched.
- otherwise, dirstate are fully restored by 'dirstateguard'
For example in timetable above, timestamp of "f" in .hg/dirstate
is restored to -1 (or less than N), and subsequent 'hg status' can
detect changes correctly.
Case (2) always causes 'repo.status()' invocation via 'repo.commit()'
just after changing files inside same wlock scope.
---- ----------------------------------- ----------------
timestamp of "f"
----------------
dirstate file-
time action mem file system
---- ----------------------------------- ---- ----- -----
N *** ***
- make file "f" clean N
- execute 'hg foobar'
....
- 'dirstate.normal("f")' N ***
(e.g. via dirty check
or previous 'repo.commit()')
- change "f", but keep size N
- 'repo.status()' (*1)
(via 'repo.commit()')
---- ----------------------------------- ---- ----- -----
At a glance, 'repo.status()' at (*1) seems to cause similar issue (=
"changed files are treated as clean"), but actually doesn't.
'dirstate._lastnormaltime' should be N at (*1) above, because
'dirstate.normal()' via dirty check is finished at N.
Therefore, "f" changed at N (= 'dirstate._lastnormaltime') is forcibly
treated as "unsure" at (*1), and changes are detected as expected (see
'dirstate.status()' for detail).
If 'hg import' is executed with '--no-commit', 'repo.status()' isn't
invoked just after changing files inside same wlock scope.
But preceding 'dirstate.normal()' is invoked inside another wlock
scope via 'cmdutil.bailifchanged()', and in-memory changes should be
flushed at the end of that scope.
Therefore, timestamp N of clean "f" should be replaced by -1, if
'dirstate.write()' is invoked at N. It means that condition of this
issue isn't satisfied.
author | FUJIWARA Katsunori <foozy@lares.dti.ne.jp> |
---|---|
date | Wed, 08 Jul 2015 17:01:09 +0900 |
parents | bd625cd4e5e7 |
children | 4414d500604f |
line wrap: on
line source
#require hardlink $ cat > nlinks.py <<EOF > import sys > from mercurial import util > for f in sorted(sys.stdin.readlines()): > f = f[:-1] > print util.nlinks(f), f > EOF $ nlinksdir() > { > find $1 -type f | python $TESTTMP/nlinks.py > } Some implementations of cp can't create hardlinks (replaces 'cp -al' on Linux): $ cat > linkcp.py <<EOF > from mercurial import util > import sys > util.copyfiles(sys.argv[1], 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 1 r1/.hg/store/phaseroots 1 r1/.hg/store/undo 1 r1/.hg/store/undo.backup.fncache 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 linking: 2 linking: 3 linking: 4 linking: 5 linking: 6 linking: 7 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 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 1 r1/.hg/store/phaseroots 1 r1/.hg/store/undo 1 r1/.hg/store/undo.backup.fncache 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 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 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("%s\n" % str(x)) >>> 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 1 r3/.hg/store/phaseroots 1 r3/.hg/store/undo 1 r3/.hg/store/undo.backup.fncache 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 2 files, 2 changesets, 2 total revisions $ cd r3 $ hg push pushing to $TESTTMP/r1 (glob) 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 1 r2/.hg/store/fncache $ hg -R r2 verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 2 files, 2 changesets, 2 total revisions $ 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 1 r2/.hg/store/fncache $ cd r3 $ hg tip --template '{rev}:{node|short}\n' 11:a6451b6bc41f $ echo bla > f1 $ hg ci -m1 $ cd .. Create hardlinked copy r4 of r3 (on Linux, we would call 'cp -al'): $ linkcp r3 r4 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-served 2 r4/.hg/cache/rbc-names-v1 2 r4/.hg/cache/rbc-revs-v1 2 r4/.hg/dirstate 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/fncache 2 r4/.hg/store/phaseroots 2 r4/.hg/store/undo 2 r4/.hg/store/undo.backup.fncache 2 r4/.hg/store/undo.backup.phaseroots 2 r4/.hg/store/undo.backupfiles 2 r4/.hg/store/undo.phaseroots 2 r4/.hg/undo.bookmarks 2 r4/.hg/undo.branch 2 r4/.hg/undo.desc 2 r4/.hg/undo.dirstate 2 r4/d1/data1 2 r4/d1/f2 2 r4/f1 Update back to revision 11 in r4 should break hardlink of file f1: $ hg -R r4 up 11 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ nlinksdir r4 2 r4/.hg/00changelog.i 1 r4/.hg/branch 2 r4/.hg/cache/branch2-served 2 r4/.hg/cache/rbc-names-v1 2 r4/.hg/cache/rbc-revs-v1 1 r4/.hg/dirstate 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/fncache 2 r4/.hg/store/phaseroots 2 r4/.hg/store/undo 2 r4/.hg/store/undo.backup.fncache 2 r4/.hg/store/undo.backup.phaseroots 2 r4/.hg/store/undo.backupfiles 2 r4/.hg/store/undo.phaseroots 2 r4/.hg/undo.bookmarks 2 r4/.hg/undo.branch 2 r4/.hg/undo.desc 2 r4/.hg/undo.dirstate 2 r4/d1/data1 2 r4/d1/f2 1 r4/f1 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 ..