push: rework the computation of fallbackheads to be correct
The previous computation tried to be smart but ended up being wrong. This was
caught by phase movement test while reworking the phase discovery logic to be
faster.
The previous logic was failing to catch case where the pushed set was not based
on a common heads (i.e. when the discovery seemed to have "over discovered"
content, outside the pushed set)
In the following graph, `e` is a common head and we `hg push -r f`. We need to
detect `c` as a fallback heads and we previous failed to do so::
e
|
d f
|/
c
|
b
|
a
The performance impact of the change seems minimal. On the most impacted
repository at hand (mozilla-try), the slowdown seems mostly mixed in the
overall noise `hg push` but seems to be in the hundred of milliseconds order of
magnitude. When using rust, we seems to be a bit faster, probably because we
leverage more accelaratd internals.
I added a couple of performance related common for further investigation later
on.
import struct
import unittest
from mercurial.node import hex
try:
from mercurial import rustext
rustext.__name__ # trigger immediate actual import
except ImportError:
rustext = None
else:
from mercurial.rustext import revlog
# this would fail already without appropriate ancestor.__package__
from mercurial.rustext.ancestor import LazyAncestors
from mercurial.testing import revlog as revlogtesting
header = struct.unpack(">I", revlogtesting.data_non_inlined[:4])[0]
@unittest.skipIf(
rustext is None,
"rustext module revlog relies on is not available",
)
class RustRevlogIndexTest(revlogtesting.RevlogBasedTestBase):
def test_heads(self):
idx = self.parseindex()
rustidx = revlog.Index(revlogtesting.data_non_inlined, header)
self.assertEqual(rustidx.headrevs(), idx.headrevs())
def test_len(self):
idx = self.parseindex()
rustidx = revlog.Index(revlogtesting.data_non_inlined, header)
self.assertEqual(len(rustidx), len(idx))
def test_ancestors(self):
rustidx = revlog.Index(revlogtesting.data_non_inlined, header)
lazy = LazyAncestors(rustidx, [3], 0, True)
# we have two more references to the index:
# - in its inner iterator for __contains__ and __bool__
# - in the LazyAncestors instance itself (to spawn new iterators)
self.assertTrue(2 in lazy)
self.assertTrue(bool(lazy))
self.assertEqual(list(lazy), [3, 2, 1, 0])
# a second time to validate that we spawn new iterators
self.assertEqual(list(lazy), [3, 2, 1, 0])
# let's check bool for an empty one
self.assertFalse(LazyAncestors(rustidx, [0], 0, False))
@unittest.skipIf(
rustext is None,
"rustext module revlog relies on is not available",
)
class RustRevlogNodeTreeClassTest(revlogtesting.RustRevlogBasedTestBase):
def test_standalone_nodetree(self):
idx = self.parserustindex()
nt = revlog.NodeTree(idx)
for i in range(4):
nt.insert(i)
bin_nodes = [entry[7] for entry in idx]
hex_nodes = [hex(n) for n in bin_nodes]
for i, node in enumerate(hex_nodes):
self.assertEqual(nt.prefix_rev_lookup(node), i)
self.assertEqual(nt.prefix_rev_lookup(node[:5]), i)
# all 4 revisions in idx (standard data set) have different
# first nybbles in their Node IDs,
# hence `nt.shortest()` should return 1 for them, except when
# the leading nybble is 0 (ambiguity with NULL_NODE)
for i, (bin_node, hex_node) in enumerate(zip(bin_nodes, hex_nodes)):
shortest = nt.shortest(bin_node)
expected = 2 if hex_node[0] == ord('0') else 1
self.assertEqual(shortest, expected)
self.assertEqual(nt.prefix_rev_lookup(hex_node[:shortest]), i)
# test invalidation (generation poisoning) detection
del idx[3]
self.assertTrue(nt.is_invalidated())
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)