view tests/test-subrepo-svn.out @ 11769:ca6cebd8734e stable

dirstate: ignore symlinks when fs cannot handle them (issue1888)

When the filesystem cannot handle the executable bit, we currently
ignore it completely when looking for modified files. Similarly, it is
impossible to set or clear the bit when the filesystem ignores it.

This patch makes Mercurial treat symbolic links the same way.

Symlinks are a little different since they manifest themselves as
small files containing a filename (the symlink target). On Windows,
these files show up as regular files, and on Linux and Mac they show
up as real symlinks.

Issue1888 presents a case where the symlink files are better ignored
from the Windows side. A Linux client creates symlinks in a working
copy which is shared over a network between Linux and Windows clients.

The Samba server is helpful and defererences the symlink when the
Windows client looks at it. This means that Mercurial on the Windows
side sees file content instead of a file name in the symlink, and
hence flags the link as modified. Ignoring the change would be much
more helpful, similarly to how Mercurial does not report any changes
when executable bits are ignored in a checkout on Windows.

An initial checkout of a symbolic link on a file system that cannot
handle symbolic links will still result in a regular file containing
the target file name as its content. Sharing such a checkout with a
Linux client will not turn the file into a symlink automatically, but
'hg revert' can fix that. After the revert, the Windows client will
see the correct file content (provided by the Samba server when it
follows the link on the Linux side) and otherwise ignore the change.

Running 'hg perfstatus' 10 times gives these results:

  Before:          After:
  min: 0.544703    min: 0.546549
  med: 0.547592    med: 0.548881
  avg: 0.549146    avg: 0.548549
  max: 0.564112    max: 0.551504

The median time is increased about 0.24%.

% create subversion repo
Checked out revision 0.
A         src
A         src/alpha
A         externals
A         externals/other
Adding         externals
Adding         externals/other
Adding         src
Adding         src/alpha
Transmitting file data ..
Committed revision 1.
At revision 1.
property 'svn:externals' set on 'src'
Sending        src

Committed revision 2.
% create hg repo
% first revision, no sub
adding a
% add first svn sub with leading whitespaces
committing subrepository s
% debugsub
path s
 source   file:///root/svn-repo/src
 revision 2

% change file in svn and hg, commit
committing subrepository s
Sending        s/alpha
Transmitting file data .
Committed revision 3.

Fetching external item into 's/externals'
External at revision 1.

At revision 3.
path s
 source   file:///root/svn-repo/src
 revision 3

% should be empty despite change to s/a

% add a commit from svn
U    alpha

Fetching external item into 'externals'
A    externals/other
Updated external to revision 1.

Updated to revision 3.
property 'svn:mime-type' set on 'alpha'
Sending        src/alpha
Transmitting file data .
Committed revision 4.
% this commit from hg will fail
committing subrepository s
abort: svn: Commit failed (details follow):
svn: File '/src/alpha' is out of date
% this commit fails because of meta changes
property 'svn:mime-type' set on 's/alpha'
committing subrepository s
abort: svn: Commit failed (details follow):
svn: File '/src/alpha' is out of date
% this commit fails because of externals changes
committing subrepository s
abort: cannot commit svn externals
% this commit fails because of externals meta changes
property 'svn:mime-type' set on 's/externals/other'
committing subrepository s
abort: cannot commit svn externals

% clone
updating to branch default
A    tc/s/alpha
 U   tc/s

Fetching external item into 'tc/s/externals'
A    tc/s/externals/other
Checked out external at revision 1.

Checked out revision 3.
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
% debugsub in clone
path s
 source   file:///root/svn-repo/src
 revision 3
% verify subrepo is contained within the repo directory
True