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
from mercurial import (
hg,
scmutil,
ui as uimod,
util,
)
chdir = os.chdir
mkdir = os.mkdir
pjoin = os.path.join
walkrepos = scmutil.walkrepos
checklink = util.checklink
u = uimod.ui.load()
sym = checklink(b'.')
hg.repository(u, b'top1', create=1)
mkdir(b'subdir')
chdir(b'subdir')
hg.repository(u, b'sub1', create=1)
mkdir(b'subsubdir')
chdir(b'subsubdir')
hg.repository(u, b'subsub1', create=1)
chdir(os.path.pardir)
if sym:
os.symlink(os.path.pardir, b'circle')
os.symlink(pjoin(b'subsubdir', b'subsub1'), b'subsub1')
def runtest():
reposet = frozenset(walkrepos(b'.', followsym=True))
if sym and (len(reposet) != 3):
print("reposet = %r" % (reposet,))
print(
(
"Found %d repositories when I should have found 3"
% (len(reposet),)
)
)
if (not sym) and (len(reposet) != 2):
print("reposet = %r" % (reposet,))
print(
(
"Found %d repositories when I should have found 2"
% (len(reposet),)
)
)
sub1set = frozenset(
(pjoin(b'.', b'sub1'), pjoin(b'.', b'circle', b'subdir', b'sub1'))
)
if len(sub1set & reposet) != 1:
print("sub1set = %r" % (sub1set,))
print("reposet = %r" % (reposet,))
print("sub1set and reposet should have exactly one path in common.")
sub2set = frozenset(
(pjoin(b'.', b'subsub1'), pjoin(b'.', b'subsubdir', b'subsub1'))
)
if len(sub2set & reposet) != 1:
print("sub2set = %r" % (sub2set,))
print("reposet = %r" % (reposet,))
print("sub2set and reposet should have exactly one path in common.")
sub3 = pjoin(b'.', b'circle', b'top1')
if sym and sub3 not in reposet:
print("reposet = %r" % (reposet,))
print("Symbolic links are supported and %s is not in reposet" % (sub3,))
runtest()
if sym:
# Simulate not having symlinks.
del os.path.samestat
sym = False
runtest()