view tests/test-convert-cvsnt-mergepoints.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 cvs repository
cvs -f -Q -d *REPO* init
% checkout #1: add foo.txt
cvs -f -Q checkout -d cvsworktmp .
cvs -f -Q add foo
cvs -f -Q add foo.txt
cvs -f ci -f -m add foo.txt foo.txt
initial revision: 1.1
% checkout #2: create MYBRANCH1 and modify foo.txt on it
cvs -f -Q checkout -d cvswork foo
cvs -f -q rtag -b -R MYBRANCH1 foo
cvs -f -Q update -P -r MYBRANCH1
cvs -f ci -f -m bar foo.txt
new revision: 1.1.2.1; previous revision: 1.1
cvs -f ci -f -m baz foo.txt
new revision: 1.1.2.2; previous revision: 1.1.2.1
% create MYBRANCH1_2 and modify foo.txt some more
cvs -f -q rtag -b -R -r MYBRANCH1 MYBRANCH1_2 foo
cvs -f -Q update -P -r MYBRANCH1_2
cvs -f ci -f -m bazzie foo.txt
new revision: 1.1.2.2.2.1; previous revision: 1.1.2.2
% create MYBRANCH1_1 and modify foo.txt yet again
cvs -f -q rtag -b -R MYBRANCH1_1 foo
cvs -f -Q update -P -r MYBRANCH1_1
cvs -f ci -f -m quux foo.txt
new revision: 1.1.4.1; previous revision: 1.1
% merge MYBRANCH1 to MYBRANCH1_1
rcsmerge: warning: conflicts during merge
cvs -f -Q update -P -jMYBRANCH1
RCS file: *REPO*/foo/foo.txt,v
retrieving revision 1.1
retrieving revision 1.1.2.2
Merging differences between 1.1 and 1.1.2.2 into foo.txt
cvs -f ci -f -m merge1+clobber foo.txt
new revision: 1.1.4.2; previous revision: 1.1.4.1
% return to trunk and merge MYBRANCH1_2
cvs -f -Q update -P -A
cvs -f -Q update -P -jMYBRANCH1_2
RCS file: *REPO*/foo/foo.txt,v
retrieving revision 1.1
retrieving revision 1.1.2.2.2.1
Merging differences between 1.1 and 1.1.2.2.2.1 into foo.txt
cvs -f ci -f -m merge2 foo.txt
new revision: 1.2; previous revision: 1.1
collecting CVS rlog
7 log entries
creating changesets
7 changeset entries
---------------------
PatchSet 1 
Date:
Author:
Branch: HEAD
Tag: (none) 
Branchpoints: MYBRANCH1_1, MYBRANCH1 
Log:
foo.txt

Members: 
	foo.txt:INITIAL->1.1 

---------------------
PatchSet 2 
Date:
Author:
Branch: MYBRANCH1
Tag: (none) 
Parent: 1
Log:
bar

Members: 
	foo.txt:1.1->1.1.2.1 

---------------------
PatchSet 3 
Date:
Author:
Branch: MYBRANCH1
Tag: (none) 
Branchpoints: MYBRANCH1_2 
Parent: 2
Log:
baz

Members: 
	foo.txt:1.1.2.1->1.1.2.2 

---------------------
PatchSet 4 
Date:
Author:
Branch: MYBRANCH1_1
Tag: (none) 
Parent: 1
Log:
quux

Members: 
	foo.txt:1.1->1.1.4.1 

---------------------
PatchSet 5 
Date:
Author:
Branch: MYBRANCH1_2
Tag: (none) 
Parent: 3
Log:
bazzie

Members: 
	foo.txt:1.1.2.2->1.1.2.2.2.1 

---------------------
PatchSet 6 
Date:
Author:
Branch: HEAD
Tag: (none) 
Parents: 1,5
Log:
merge

Members: 
	foo.txt:1.1->1.2 

---------------------
PatchSet 7 
Date:
Author:
Branch: MYBRANCH1_1
Tag: (none) 
Parents: 4,3
Log:
merge

Members: 
	foo.txt:1.1.4.1->1.1.4.2