contrib/undumprevlog

clone: properly exclude rev-branch-cache from post clone cache warming

When adding "CACHE_REV_BRANCH" to "CACHES_ALL" in e51161b12c7e, I did not
expected it to impact the clone steps. However the "CACHES_POST_CLONE" set is
created rather creatively. (we should fix that, but not on stable)

The benchmark caught a quite significant slowdown one hardlink and ssh-stream
clones. Such slow down can be reduced to around ~5% by fully warming the cache
before the clone. However keeping this expensive step away from the clone
operation fully fix the slowdown and preserve the initial intend.


Example slowdow for hardlink clone

### benchmark.name                               = hg.command.clone
  # bin-env-vars.hg.flavor                       = default
  # bin-env-vars.hg.py-re2-module                = default
  # benchmark.variants.explicit-rev              = none
  # benchmark.variants.issue6528                 = default
  # benchmark.variants.protocol                  = local-hardlink
  # benchmark.variants.pulled-delta-reuse-policy = default
  # benchmark.variants.resource-usage            = default
  # benchmark.variants.validate                  = default
 ## data-env-vars.name = netbeans-2018-08-01-zstd-sparse-revlog
6.8.2:  19.799752
6.9rc0: 29.017493  (+46.55%, +9.22)
after:  19.929341

 ## data-env-vars.name = mercurial-public-2018-08-01-zstd-sparse-revlog
6.8.2:  0.468020
6.9rc0: 1.701294 (+263.51%, +1.23)
after:  0.471934

 ## data-env-vars.name = pypy-2024-03-22-zstd-sparse-revlog
6.8.2:  2.397564
6.9rc0: 5.666641 (+137.41%, +3.28)
after:  2.428085

#!/usr/bin/env python3
# Undump a dump from dumprevlog
# $ hg init
# $ undumprevlog < repo.dump


import sys
from mercurial.node import bin
from mercurial import (
    encoding,
    revlog,
    transaction,
    vfs as vfsmod,
)
from mercurial.utils import procutil

from mercurial.revlogutils import (
    constants as revlog_constants,
)

for fp in (sys.stdin, sys.stdout, sys.stderr):
    procutil.setbinary(fp)

opener = vfsmod.vfs(b'.', False)
tr = transaction.transaction(
    sys.stderr.write, opener, {b'store': opener}, b"undump.journal"
)
while True:
    l = sys.stdin.readline()
    if not l:
        break
    if l.startswith("file:"):
        f = encoding.strtolocal(l[6:-1])
        assert f.endswith(b'.i')
        r = revlog.revlog(
            opener,
            target=(revlog_constants.KIND_OTHER, b'undump-revlog'),
            radix=f[:-2],
        )
        procutil.stdout.write(b'%s\n' % f)
    elif l.startswith("node:"):
        n = bin(l[6:-1])
    elif l.startswith("linkrev:"):
        lr = int(l[9:-1])
    elif l.startswith("parents:"):
        p = l[9:-1].split()
        p1 = bin(p[0])
        p2 = bin(p[1])
    elif l.startswith("length:"):
        length = int(l[8:-1])
        sys.stdin.readline()  # start marker
        d = encoding.strtolocal(sys.stdin.read(length))
        sys.stdin.readline()  # end marker
        r.addrevision(d, tr, lr, p1, p2)

tr.close()