filectx: fix cmp() of file starting with '\1\n'
If file data starts with '\1\n', it will be escaped in the revlog to
create an empty metadata block, thus adding four bytes to the size in
the revlog size index. There's no way to detect that this has happened
in filelog.size() faster than decompressing each revision [1].
For filectx.cmp(), we have the size of the file in the working directory
available. If it differs by exactly four bytes, it may be this case, so
do a full comparison.
[1]: http://markmail.org/message/5akdbmmqx7vq2fsg
# reproduce issue2264, issue2516
create test repo
$ cat <<EOF >> $HGRCPATH
> [extensions]
> transplant =
> graphlog =
> EOF
$ hg init repo
$ cd repo
$ template="{rev} {desc|firstline} [{branch}]\n"
# we need to start out with two changesets on the default branch
# in order to avoid the cute little optimization where transplant
# pulls rather than transplants
add initial changesets
$ echo feature1 > file1
$ hg ci -Am"feature 1"
adding file1
$ echo feature2 >> file2
$ hg ci -Am"feature 2"
adding file2
# The changes to 'bugfix' are enough to show the bug: in fact, with only
# those changes, it's a very noisy crash ("RuntimeError: nothing
# committed after transplant"). But if we modify a second file in the
# transplanted changesets, the bug is much more subtle: transplant
# silently drops the second change to 'bugfix' on the floor, and we only
# see it when we run 'hg status' after transplanting. Subtle data loss
# bugs are worse than crashes, so reproduce the subtle case here.
commit bug fixes on bug fix branch
$ hg branch fixes
marked working directory as branch fixes
(branches are permanent and global, did you want a bookmark?)
$ echo fix1 > bugfix
$ echo fix1 >> file1
$ hg ci -Am"fix 1"
adding bugfix
$ echo fix2 > bugfix
$ echo fix2 >> file1
$ hg ci -Am"fix 2"
$ hg glog --template="$template"
@ 3 fix 2 [fixes]
|
o 2 fix 1 [fixes]
|
o 1 feature 2 [default]
|
o 0 feature 1 [default]
transplant bug fixes onto release branch
$ hg update 0
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg branch release
marked working directory as branch release
(branches are permanent and global, did you want a bookmark?)
$ hg transplant 2 3
applying [0-9a-f]{12} (re)
[0-9a-f]{12} transplanted to [0-9a-f]{12} (re)
applying [0-9a-f]{12} (re)
[0-9a-f]{12} transplanted to [0-9a-f]{12} (re)
$ hg glog --template="$template"
@ 5 fix 2 [release]
|
o 4 fix 1 [release]
|
| o 3 fix 2 [fixes]
| |
| o 2 fix 1 [fixes]
| |
| o 1 feature 2 [default]
|/
o 0 feature 1 [default]
$ hg status
$ hg status --rev 0:4
M file1
A bugfix
$ hg status --rev 4:5
M bugfix
M file1
now test that we fixed the bug for all scripts/extensions
$ cat > $TESTTMP/committwice.py <<__EOF__
> from mercurial import ui, hg, match, node
> from time import sleep
>
> def replacebyte(fn, b):
> f = open(fn, "rb+")
> f.seek(0, 0)
> f.write(b)
> f.close()
>
> def printfiles(repo, rev):
> print "revision %s files: %s" % (rev, repo[rev].files())
>
> repo = hg.repository(ui.ui(), '.')
> assert len(repo) == 6, \
> "initial: len(repo): %d, expected: 6" % len(repo)
>
> replacebyte("bugfix", "u")
> sleep(2)
> try:
> print "PRE: len(repo): %d" % len(repo)
> wlock = repo.wlock()
> lock = repo.lock()
> replacebyte("file1", "x")
> repo.commit(text="x", user="test", date=(0, 0))
> replacebyte("file1", "y")
> repo.commit(text="y", user="test", date=(0, 0))
> print "POST: len(repo): %d" % len(repo)
> finally:
> lock.release()
> wlock.release()
> printfiles(repo, 6)
> printfiles(repo, 7)
> __EOF__
$ $PYTHON $TESTTMP/committwice.py
PRE: len(repo): 6
POST: len(repo): 8
revision 6 files: ['bugfix', 'file1']
revision 7 files: ['file1']
Do a size-preserving modification outside of that process
$ echo abcd > bugfix
$ hg status
M bugfix
$ hg log --template "{rev} {desc} {files}\n" -r5:
5 fix 2 bugfix file1
6 x bugfix file1
7 y file1