branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
import os
import sys
import time
from mercurial import (
commands,
hg,
pycompat,
ui as uimod,
util,
)
TESTDIR = os.environ["TESTDIR"]
BUNDLEPATH = os.path.join(TESTDIR, 'bundles', 'test-no-symlinks.hg')
# only makes sense to test on os which supports symlinks
if not getattr(os, "symlink", False):
sys.exit(80) # SKIPPED_STATUS defined in run-tests.py
u = uimod.ui.load()
# hide outer repo
hg.peer(u, {}, b'.', create=True)
# unbundle with symlink support
hg.peer(u, {}, b'test0', create=True)
repo = hg.repository(u, b'test0')
commands.unbundle(u, repo, pycompat.fsencode(BUNDLEPATH), update=True)
# wait a bit, or the status call wont update the dirstate
time.sleep(1)
commands.status(u, repo)
# now disable symlink support -- this is what os.symlink would do on a
# non-symlink file system
def symlink_failure(src, dst):
raise OSError(1, "Operation not permitted")
os.symlink = symlink_failure
def islink_failure(path):
return False
os.path.islink = islink_failure
# dereference links as if a Samba server has exported this to a
# Windows client
for f in b'test0/a.lnk', b'test0/d/b.lnk':
os.unlink(f)
fp = open(f, 'wb')
fp.write(util.readfile(f[:-4]))
fp.close()
# reload repository
u = uimod.ui.load()
repo = hg.repository(u, b'test0')
commands.status(u, repo)
# try unbundling a repo which contains symlinks
u = uimod.ui.load()
repo = hg.repository(u, b'test1', create=True)
commands.unbundle(u, repo, pycompat.fsencode(BUNDLEPATH), update=True)