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.
#!/usr/bin/env python3
# Filter output by pyflakes to control which warnings we check
import re
import sys
lines = []
for line in sys.stdin:
# We blacklist tests that are too noisy for us
pats = [
r"undefined name 'WindowsError'",
r"redefinition of unused '[^']+' from line",
# for cffi, allow re-exports from pure.*
r"cffi/[^:]*:.*\bimport \*' used",
r"cffi/[^:]*:.*\*' imported but unused",
]
keep = True
for pat in pats:
if re.search(pat, line):
keep = False
break # pattern matches
if keep:
fn = line.split(':', 1)[0]
with open(fn, 'rb') as f:
data = f.read()
if b'no-' b'check-code' in data:
continue
lines.append(line)
for line in lines:
sys.stdout.write(line)
print()