branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
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()