view tests/test-newbranch @ 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%.

#!/bin/sh

branchcache=.hg/branchheads.cache

hg init t
cd t
hg branches

echo foo > a
hg add a
hg ci -m "initial" -d "1000000 0"
hg branch foo
hg branch
hg ci -m "add branch name" -d "1000000 0"
hg branch bar
hg ci -m "change branch name" -d "1000000 0"
echo % branch shadowing
hg branch default
hg branch -f default
hg ci -m "clear branch name" -d "1000000 0"

echo % there should be only one default branch head
hg heads .

hg co foo
hg branch
echo bleah > a
hg ci -m "modify a branch" -d "1000000 0"

hg merge default
hg branch
hg ci -m "merge" -d "1000000 0"
hg log

hg branches
hg branches -q

echo % test for invalid branch cache
hg rollback
cp $branchcache .hg/bc-invalid
hg log -r foo
cp .hg/bc-invalid $branchcache
hg --debug log -r foo
rm $branchcache
echo corrupted > $branchcache
hg log -qr foo
cat $branchcache

echo % push should update the branch cache
hg init ../target
echo % pushing just rev 0
hg push -qr 0 ../target
cat ../target/$branchcache
echo % pushing everything
hg push -qf ../target
cat ../target/$branchcache

echo % update with no arguments: tipmost revision of the current branch
hg up -q -C 0
hg up -q
hg id
hg up -q 1
hg up -q
hg id
hg branch foobar
hg up

echo % fastforward merge
hg branch ff
echo ff > ff
hg ci -Am'fast forward' -d '1000000 0'
hg up foo
hg merge ff
hg branch
hg commit -m'Merge ff into foo' -d '1000000 0'
hg parents
hg manifest

echo % test merging, add 3 default heads and one test head
cd ..
hg init merges
cd merges
echo a > a
hg ci -Ama

echo b > b
hg ci -Amb

hg up 0
echo c > c
hg ci -Amc

hg up 0
echo d > d
hg ci -Amd

hg up 0
hg branch test
echo e >> e
hg ci -Ame

hg log

echo % implicit merge with test branch as parent
hg merge
hg up -C default
echo % implicit merge with default branch as parent
hg merge
echo % 3 branch heads, explicit merge required
hg merge 2
hg ci -m merge
echo % 2 branch heads, implicit merge works
hg merge