view tests/test-symlinks.t @ 17616:9535a0dc41f2

store: implement fncache basic path encoding in C

(This is not yet enabled; it will be turned on in a followup patch.)

The path encoding performed by fncache is complex and (perhaps
surprisingly) slow enough to negatively affect the overall performance
of Mercurial.

For a short path (< 120 bytes), the Python code can be reduced to a fairly
tractable state machine that either determines that nothing needs to be
done in a single pass, or performs the encoding in a second pass.

For longer paths, we avoid the more complicated hashed encoding scheme
for now, and fall back to Python.

Raw performance: I measured in a repo containing 150,000 files in its tip
manifest, with a median path name length of 57 bytes, and 95th percentile
of 96 bytes.

In this repo, the Python code takes 3.1 seconds to encode all path
names, while the hybrid C-and-Python code (called from Python) takes
0.21 seconds, for a speedup of about 14.

Across several other large repositories, I've measured the speedup from
the C code at between 26x and 40x.

For path names above 120 bytes where we must fall back to Python for
hashed encoding, the speedup is about 1.7x.  Thus absolute performance
will depend strongly on the characteristics of a particular repository.

  $ "$TESTDIR/hghave" symlink || exit 80

== tests added in 0.7 ==

  $ hg init test-symlinks-0.7; cd test-symlinks-0.7;
  $ touch foo; ln -s foo bar;

import with addremove -- symlink walking should _not_ screwup.

  $ hg addremove
  adding bar
  adding foo

commit -- the symlink should _not_ appear added to dir state

  $ hg commit -m 'initial'

  $ touch bomb

again, symlink should _not_ show up on dir state

  $ hg addremove
  adding bomb

Assert screamed here before, should go by without consequence

  $ hg commit -m 'is there a bug?'
  $ cd ..


== fifo & ignore ==

  $ hg init test; cd test;

  $ mkdir dir
  $ touch a.c dir/a.o dir/b.o

test what happens if we want to trick hg

  $ hg commit -A -m 0
  adding a.c
  adding dir/a.o
  adding dir/b.o
  $ echo "relglob:*.o" > .hgignore
  $ rm a.c
  $ rm dir/a.o
  $ rm dir/b.o
  $ mkdir dir/a.o
  $ ln -s nonexistent dir/b.o
  $ mkfifo a.c

it should show a.c, dir/a.o and dir/b.o deleted

  $ hg status
  M dir/b.o
  ! a.c
  ! dir/a.o
  ? .hgignore
  $ hg status a.c
  a.c: unsupported file type (type is fifo)
  ! a.c
  $ cd ..


== symlinks from outside the tree ==

test absolute path through symlink outside repo

  $ p=`pwd`
  $ hg init x
  $ ln -s x y
  $ cd x
  $ touch f
  $ hg add f
  $ hg status "$p"/y/f
  A f

try symlink outside repo to file inside

  $ ln -s x/f ../z

this should fail

  $ hg status ../z && { echo hg mistakenly exited with status 0; exit 1; } || :
  abort: ../z not under root
  $ cd ..


== cloning symlinks ==
  $ hg init clone; cd clone;

try cloning symlink in a subdir
1. commit a symlink

  $ mkdir -p a/b/c
  $ cd a/b/c
  $ ln -s /path/to/symlink/source demo
  $ cd ../../..
  $ hg stat
  ? a/b/c/demo
  $ hg commit -A -m 'add symlink in a/b/c subdir'
  adding a/b/c/demo

2. clone it

  $ cd ..
  $ hg clone clone clonedest
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved


== symlink and git diffs ==

git symlink diff

  $ cd clonedest
  $ hg diff --git -r null:tip
  diff --git a/a/b/c/demo b/a/b/c/demo
  new file mode 120000
  --- /dev/null
  +++ b/a/b/c/demo
  @@ -0,0 +1,1 @@
  +/path/to/symlink/source
  \ No newline at end of file
  $ hg export --git tip > ../sl.diff

import git symlink diff

  $ hg rm a/b/c/demo
  $ hg commit -m'remove link'
  $ hg import ../sl.diff
  applying ../sl.diff
  $ hg diff --git -r 1:tip
  diff --git a/a/b/c/demo b/a/b/c/demo
  new file mode 120000
  --- /dev/null
  +++ b/a/b/c/demo
  @@ -0,0 +1,1 @@
  +/path/to/symlink/source
  \ No newline at end of file

== symlinks and addremove ==

directory moved and symlinked

  $ mkdir foo
  $ touch foo/a
  $ hg ci -Ama
  adding foo/a
  $ mv foo bar
  $ ln -s bar foo

now addremove should remove old files

  $ hg addremove
  adding bar/a
  adding foo
  removing foo/a
  $ cd ..

== root of repository is symlinked ==

  $ hg init root
  $ ln -s root link
  $ cd root
  $ echo foo > foo
  $ hg status
  ? foo
  $ hg status ../link
  ? foo
  $ hg add foo
  $ hg cp foo "$TESTTMP/link/bar"
  foo has not been committed yet, so no copy data will be stored for bar.
  $ cd ..


  $ hg init b
  $ cd b
  $ ln -s nothing dangling
  $ hg commit -m 'commit symlink without adding' dangling
  abort: dangling: file not tracked!
  [255]
  $ hg add dangling
  $ hg commit -m 'add symlink'

  $ hg tip -v
  changeset:   0:cabd88b706fc
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       dangling
  description:
  add symlink
  
  
  $ hg manifest --debug
  2564acbe54bbbedfbf608479340b359f04597f80 644 @ dangling
  $ "$TESTDIR/readlink.py" dangling
  dangling -> nothing

  $ rm dangling
  $ ln -s void dangling
  $ hg commit -m 'change symlink'
  $ "$TESTDIR/readlink.py" dangling
  dangling -> void


modifying link

  $ rm dangling
  $ ln -s empty dangling
  $ "$TESTDIR/readlink.py" dangling
  dangling -> empty


reverting to rev 0:

  $ hg revert -r 0 -a
  reverting dangling
  $ "$TESTDIR/readlink.py" dangling
  dangling -> nothing


backups:

  $ "$TESTDIR/readlink.py" *.orig
  dangling.orig -> empty
  $ rm *.orig
  $ hg up -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

copies

  $ hg cp -v dangling dangling2
  copying dangling to dangling2
  $ hg st -Cmard
  A dangling2
    dangling
  $ "$TESTDIR/readlink.py" dangling dangling2
  dangling -> void
  dangling2 -> void


Issue995: hg copy -A incorrectly handles symbolic links

  $ hg up -C
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ mkdir dir
  $ ln -s dir dirlink
  $ hg ci -qAm 'add dirlink'
  $ mkdir newdir
  $ mv dir newdir/dir
  $ mv dirlink newdir/dirlink
  $ hg mv -A dirlink newdir/dirlink

  $ cd ..