bisect: avoid copying ancestor list for non-merge commits
During a bisection, hg needs to compute a list of all ancestors for every
candidate commit. This is accomplished via a bottom-up traversal of the set of
candidates, during which each revision's ancestor list is populated using the
ancestor list of its parent(s). Previously, this involved copying the entire
list, which could be very long in if the bisection range was large.
To help improve this, we can observe that each candidate commit is visited
exactly once, at which point its ancestor list is copied into its children's
lists and then dropped. In the case of non-merge commits, a commit's ancestor
list consists exactly of its parent's list plus itself. This means that we can
trivially reuse the parent's existing list for one of its non-merge children,
which avoids copying entirely if that commit is the parent's only child. This
makes bisections over linear ranges of commits much faster.
During some informal testing in the large publicly-available `mozilla-central`
repository, this noticeably sped up bisections over large ranges of history:
Setup:
$ cd mozilla-central
$ hg bisect --reset
$ hg bisect --good 0
$ hg log -r tip -T '{rev}\n'
628417
Test:
$ time hg bisect --bad tip --noupdate
Before:
real 3m35.927s
user 3m35.553s
sys 0m0.319s
After:
real 1m41.142s
user 1m40.810s
sys 0m0.285s
from mercurial import demandimport
demandimport.enable()
from mercurial import (
error,
pycompat,
ui as uimod,
url,
util,
)
from mercurial.utils import (
stringutil,
urlutil,
)
urlerr = util.urlerr
urlreq = util.urlreq
class myui(uimod.ui):
def interactive(self):
return False
origui = myui.load()
def writeauth(items):
ui = origui.copy()
for name, value in items.items():
ui.setconfig(b'auth', name, value)
return ui
def _stringifyauthinfo(ai):
if ai is None:
return ai
realm, authuris, user, passwd = ai
return (
pycompat.strurl(realm),
[pycompat.strurl(u) for u in authuris],
pycompat.strurl(user),
pycompat.strurl(passwd),
)
def test(auth, urls=None):
print('CFG:', pycompat.sysstr(stringutil.pprint(auth, bprefix=True)))
prefixes = set()
for k in auth:
prefixes.add(k.split(b'.', 1)[0])
for p in prefixes:
for name in (b'.username', b'.password'):
if (p + name) not in auth:
auth[p + name] = p
auth = {k: v for k, v in auth.items() if v is not None}
ui = writeauth(auth)
def _test(uri):
print('URI:', pycompat.strurl(uri))
try:
pm = url.passwordmgr(ui, urlreq.httppasswordmgrwithdefaultrealm())
u, authinfo = urlutil.url(uri).authinfo()
if authinfo is not None:
pm.add_password(*_stringifyauthinfo(authinfo))
print(
' ',
tuple(
pycompat.strurl(a)
for a in pm.find_user_password('test', pycompat.strurl(u))
),
)
except error.Abort:
print(' ', 'abort')
if not urls:
urls = [
b'http://example.org/foo',
b'http://example.org/foo/bar',
b'http://example.org/bar',
b'https://example.org/foo',
b'https://example.org/foo/bar',
b'https://example.org/bar',
b'https://x@example.org/bar',
b'https://y@example.org/bar',
]
for u in urls:
_test(u)
print('\n*** Test in-uri schemes\n')
test({b'x.prefix': b'http://example.org'})
test({b'x.prefix': b'https://example.org'})
test({b'x.prefix': b'http://example.org', b'x.schemes': b'https'})
test({b'x.prefix': b'https://example.org', b'x.schemes': b'http'})
print('\n*** Test separately configured schemes\n')
test({b'x.prefix': b'example.org', b'x.schemes': b'http'})
test({b'x.prefix': b'example.org', b'x.schemes': b'https'})
test({b'x.prefix': b'example.org', b'x.schemes': b'http https'})
print('\n*** Test prefix matching\n')
test(
{
b'x.prefix': b'http://example.org/foo',
b'y.prefix': b'http://example.org/bar',
}
)
test(
{
b'x.prefix': b'http://example.org/foo',
b'y.prefix': b'http://example.org/foo/bar',
}
)
test({b'x.prefix': b'*', b'y.prefix': b'https://example.org/bar'})
print('\n*** Test user matching\n')
test(
{
b'x.prefix': b'http://example.org/foo',
b'x.username': None,
b'x.password': b'xpassword',
},
urls=[b'http://y@example.org/foo'],
)
test(
{
b'x.prefix': b'http://example.org/foo',
b'x.username': None,
b'x.password': b'xpassword',
b'y.prefix': b'http://example.org/foo',
b'y.username': b'y',
b'y.password': b'ypassword',
},
urls=[b'http://y@example.org/foo'],
)
test(
{
b'x.prefix': b'http://example.org/foo/bar',
b'x.username': None,
b'x.password': b'xpassword',
b'y.prefix': b'http://example.org/foo',
b'y.username': b'y',
b'y.password': b'ypassword',
},
urls=[b'http://y@example.org/foo/bar'],
)
print('\n*** Test user matching with name in prefix\n')
# prefix, username and URL have the same user
test(
{
b'x.prefix': b'https://example.org/foo',
b'x.username': None,
b'x.password': b'xpassword',
b'y.prefix': b'http://y@example.org/foo',
b'y.username': b'y',
b'y.password': b'ypassword',
},
urls=[b'http://y@example.org/foo'],
)
# Prefix has a different user from username and URL
test(
{
b'y.prefix': b'http://z@example.org/foo',
b'y.username': b'y',
b'y.password': b'ypassword',
},
urls=[b'http://y@example.org/foo'],
)
# Prefix has a different user from URL; no username
test(
{b'y.prefix': b'http://z@example.org/foo', b'y.password': b'ypassword'},
urls=[b'http://y@example.org/foo'],
)
# Prefix and URL have same user, but doesn't match username
test(
{
b'y.prefix': b'http://y@example.org/foo',
b'y.username': b'z',
b'y.password': b'ypassword',
},
urls=[b'http://y@example.org/foo'],
)
# Prefix and URL have the same user; no username
test(
{b'y.prefix': b'http://y@example.org/foo', b'y.password': b'ypassword'},
urls=[b'http://y@example.org/foo'],
)
# Prefix user, but no URL user or username
test(
{b'y.prefix': b'http://y@example.org/foo', b'y.password': b'ypassword'},
urls=[b'http://example.org/foo'],
)
def testauthinfo(fullurl, authurl):
print('URIs:', fullurl, authurl)
pm = urlreq.httppasswordmgrwithdefaultrealm()
ai = _stringifyauthinfo(
urlutil.url(pycompat.bytesurl(fullurl)).authinfo()[1]
)
pm.add_password(*ai)
print(pm.find_user_password('test', authurl))
print('\n*** Test urllib2 and urlutil.url\n')
testauthinfo('http://user@example.com:8080/foo', 'http://example.com:8080/foo')