view tests/test-bheads @ 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

heads()
{
    hg heads --template '{rev}: {desc|firstline|strip} ({branches})\n' "$@"
}

hg init a
cd a
echo 'root' >root
hg add root
hg commit -m "Adding root node"
heads
echo '-------'
heads .

echo '======='
echo 'a' >a
hg add a
hg branch a
hg commit -m "Adding a branch"
heads
echo '-------'
heads .

echo '======='
hg update -C 0
echo 'b' >b
hg add b
hg branch b
hg commit -m "Adding b branch"
heads
echo '-------'
heads .

echo '======='
echo 'bh1' >bh1
hg add bh1
hg commit -m "Adding b branch head 1"
heads
echo '-------'
heads .

echo '======='
hg update -C 2
echo 'bh2' >bh2
hg add bh2
hg commit -m "Adding b branch head 2"
heads
echo '-------'
heads .

echo '======='
hg update -C 2
echo 'bh3' >bh3
hg add bh3
hg commit -m "Adding b branch head 3"
heads
echo '-------'
heads .

echo '======='
hg merge 4
hg commit -m "Merging b branch head 2 and b branch head 3"
heads
echo '-------'
heads .

echo '======='
echo 'c' >c
hg add c
hg branch c
hg commit -m "Adding c branch"
heads
echo '-------'
heads .

echo '======='
heads -r 3 .
echo $?
echo '-------'
heads -r 2 .
echo $?
echo '-------'
hg update -C 4
echo $?
echo '-------'
heads -r 3 .
echo $?
echo '-------'
heads -r 2 .
echo $?
echo '-------'
heads -r 7 .
echo $?

echo '======='
for i in 0 1 2 3 4 5 6 7; do
    hg update -C "$i"
    heads
    echo '-------'
    heads .
    echo '-------'
done

echo '======='
for i in a b c z; do
    heads "$i"
    echo '-------'
done

echo '======='
heads 0 1 2 3 4 5 6 7

echo '% topological heads'
heads -t

echo '______________'
cd ..

hg init newheadmsg
cd newheadmsg

echo '% created new head message'
echo '% init: no msg'
echo 1 > a
hg ci -Am "a0: Initial root"
echo 2 >> a
hg ci -m "a1 (HN)"

hg branch b
echo 1 > b
hg ci -Am "b2: Initial root for branch b"
echo 2 >> b
hg ci -m "b3 (HN)"

echo '% case NN: msg'
hg up -q null
hg branch -f b
echo 1 > bb
hg ci -Am "b4 (NN): new topo root for branch b"

echo '% case HN: no msg'
echo 2 >> bb
hg ci -m "b5 (HN)"

echo '% case BN: msg'
hg branch -f default
echo 1 > aa
hg ci -Am "a6 (BN): new branch root"

echo '% case CN: msg'
hg up -q 4
echo 3 >> bbb
hg ci -Am "b7 (CN): regular new head"

echo '% case BB: msg'
hg up -q 4
hg merge -q 3
hg branch -f default
hg ci -m "a8 (BB): weird new branch root"

echo '% case CB: msg'
hg up -q 4
hg merge -q 1
hg ci -m "b9 (CB): new head from branch merge"

echo '% case HB: no msg'
hg up -q 7
hg merge -q 6
hg ci -m "b10 (HB): continuing head from branch merge"

echo '% case CC: msg'
hg up -q 4
hg merge -q 2
hg ci -m "b11 (CC): new head from merge"

echo '% case CH: no msg'
hg up -q 2
hg merge -q 10
hg ci -m "b12 (CH): continuing head from merge"

echo '% case HH: no msg'
hg merge -q 3
hg ci -m "b12 (HH): merging two heads"