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.
# Extension dedicated to test patch.diff() upgrade modes
from mercurial import (
error,
logcmdutil,
patch,
pycompat,
registrar,
scmutil,
)
cmdtable = {}
command = registrar.command(cmdtable)
@command(
b'autodiff',
[(b'', b'git', b'', b'git upgrade mode (yes/no/auto/warn/abort)')],
b'[OPTION]... [FILE]...',
)
def autodiff(ui, repo, *pats, **opts):
opts = pycompat.byteskwargs(opts)
diffopts = patch.difffeatureopts(ui, opts)
git = opts.get(b'git', b'no')
brokenfiles = set()
losedatafn = None
if git in (b'yes', b'no'):
diffopts.git = git == b'yes'
diffopts.upgrade = False
elif git == b'auto':
diffopts.git = False
diffopts.upgrade = True
elif git == b'warn':
diffopts.git = False
diffopts.upgrade = True
def losedatafn(fn=None, **kwargs):
brokenfiles.add(fn)
return True
elif git == b'abort':
diffopts.git = False
diffopts.upgrade = True
def losedatafn(fn=None, **kwargs):
raise error.Abort(b'losing data for %s' % fn)
else:
raise error.Abort(b'--git must be yes, no or auto')
ctx1, ctx2 = logcmdutil.revpair(repo, [])
m = scmutil.match(ctx2, pats, opts)
it = patch.diff(
repo,
ctx1.node(),
ctx2.node(),
match=m,
opts=diffopts,
losedatafn=losedatafn,
)
for chunk in it:
ui.write(chunk)
for fn in sorted(brokenfiles):
ui.write((b'data lost for: %s\n' % fn))