hg: obtain lock when creating share from pooled repo (
issue5104)
There are race conditions between clients performing a shared clone
to pooled storage:
1) Clients race to create the new shared repo in the pool directory
2) 1 client is seeding the repo in the pool directory and another goes
to share it before it is fully cloned
We prevent these race conditions by obtaining a lock in the pool
directory that is derived from the name of the repo we will be
accessing.
To test this, a simple generic "lockdelay" extension has been added.
The extension inserts an optional, configurable delay before or after
lock acquisition. In the test, we delay 2 seconds after lock acquisition
in the first process and 1 second before lock acquisition in the 2nd
process. This means the first process has 1s to obtain the lock. There
is a race condition here. If we encounter it in the wild, we could
change the dummy extension to wait on the lock file to appear instead
of relying on timing. But that's more complicated. Let's see what
happens first.
$ hg init
audit of .hg
$ hg add .hg/00changelog.i
abort: path contains illegal component: .hg/00changelog.i (glob)
[255]
#if symlink
Symlinks
$ mkdir a
$ echo a > a/a
$ hg ci -Ama
adding a/a
$ ln -s a b
$ echo b > a/b
$ hg add b/b
abort: path 'b/b' traverses symbolic link 'b' (glob)
[255]
$ hg add b
should still fail - maybe
$ hg add b/b
abort: path 'b/b' traverses symbolic link 'b' (glob)
[255]
$ hg commit -m 'add symlink b'
Test symlink traversing when accessing history:
-----------------------------------------------
(build a changeset where the path exists as a directory)
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkdir b
$ echo c > b/a
$ hg add b/a
$ hg ci -m 'add directory b'
created new head
Test that hg cat does not do anything wrong the working copy has 'b' as directory
$ hg cat b/a
c
$ hg cat -r "desc(directory)" b/a
c
$ hg cat -r "desc(symlink)" b/a
b/a: no such file in rev bc151a1f53bd
[1]
Test that hg cat does not do anything wrong the working copy has 'b' as a symlink (issue4749)
$ hg up 'desc(symlink)'
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg cat b/a
b/a: no such file in rev bc151a1f53bd
[1]
$ hg cat -r "desc(directory)" b/a
c
$ hg cat -r "desc(symlink)" b/a
b/a: no such file in rev bc151a1f53bd
[1]
#endif
unbundle tampered bundle
$ hg init target
$ cd target
$ hg unbundle "$TESTDIR/bundles/tampered.hg"
adding changesets
adding manifests
adding file changes
added 5 changesets with 6 changes to 6 files (+4 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
attack .hg/test
$ hg manifest -r0
.hg/test
$ hg update -Cr0
abort: path contains illegal component: .hg/test (glob)
[255]
attack foo/.hg/test
$ hg manifest -r1
foo/.hg/test
$ hg update -Cr1
abort: path 'foo/.hg/test' is inside nested repo 'foo' (glob)
[255]
attack back/test where back symlinks to ..
$ hg manifest -r2
back
back/test
#if symlink
$ hg update -Cr2
abort: path 'back/test' traverses symbolic link 'back'
[255]
#else
('back' will be a file and cause some other system specific error)
$ hg update -Cr2
abort: * (glob)
[255]
#endif
attack ../test
$ hg manifest -r3
../test
$ hg update -Cr3
abort: path contains illegal component: ../test (glob)
[255]
attack /tmp/test
$ hg manifest -r4
/tmp/test
$ hg update -Cr4
abort: path contains illegal component: /tmp/test (glob)
[255]
$ cd ..