internals: document CBOR utilization
I spoke with some people at Mozilla about CBOR and they advised me
that we should be careful about the subset of CBOR we use in order
to mitigate security, performance, and compatibility concerns.
This commit establishes a document that attempts to formalize our
use of CBOR.
Its main limitations are on what types are allowed. It explicitly
enumerates which types are supported. Notable missing features
include:
* Indefinite-length arrays and maps
* Text strings (bytes all the way)
* Floats
* Date/time types
* Big integers
* Use of indefinite-length byte strings for map keys, values in
containers.
If we have a need for any of these, we can have a discussion about
them when the time comes.
Differential Revision: https://phab.mercurial-scm.org/D4412
from __future__ import absolute_import, print_function
import os
import stat
import sys
from mercurial.node import hex
from mercurial import (
context,
diffutil,
encoding,
hg,
scmutil,
ui as uimod,
)
print_ = print
def print(*args, **kwargs):
"""print() wrapper that flushes stdout buffers to avoid py3 buffer issues
We could also just write directly to sys.stdout.buffer the way the
ui object will, but this was easier for porting the test.
"""
print_(*args, **kwargs)
sys.stdout.flush()
def printb(data, end=b'\n'):
out = getattr(sys.stdout, 'buffer', sys.stdout)
out.write(data + end)
out.flush()
u = uimod.ui.load()
repo = hg.repository(u, b'test1', create=1)
os.chdir('test1')
# create 'foo' with fixed time stamp
f = open('foo', 'wb')
f.write(b'foo\n')
f.close()
os.utime('foo', (1000, 1000))
# add+commit 'foo'
repo[None].add([b'foo'])
repo.commit(text=b'commit1', date=b"0 0")
d = repo[None][b'foo'].date()
if os.name == 'nt':
d = d[:2]
print("workingfilectx.date = (%d, %d)" % d)
# test memctx with non-ASCII commit message
def filectxfn(repo, memctx, path):
return context.memfilectx(repo, memctx, b"foo", b"")
ctx = context.memctx(repo, [b'tip', None],
encoding.tolocal(b"Gr\xc3\xbcezi!"),
[b"foo"], filectxfn)
ctx.commit()
for enc in "ASCII", "Latin-1", "UTF-8":
encoding.encoding = enc
printb(b"%-8s: %s" % (enc.encode('ascii'), repo[b"tip"].description()))
# test performing a status
def getfilectx(repo, memctx, f):
fctx = memctx.parents()[0][f]
data, flags = fctx.data(), fctx.flags()
if f == b'foo':
data += b'bar\n'
return context.memfilectx(
repo, memctx, f, data, b'l' in flags, b'x' in flags)
ctxa = repo[0]
ctxb = context.memctx(repo, [ctxa.node(), None], b"test diff", [b"foo"],
getfilectx, ctxa.user(), ctxa.date())
print(ctxb.status(ctxa))
# test performing a diff on a memctx
diffopts = diffutil.diffallopts(repo.ui, {b'git': True})
for d in ctxb.diff(ctxa, opts=diffopts):
printb(d, end=b'')
# test safeness and correctness of "ctx.status()"
print('= checking context.status():')
# ancestor "wcctx ~ 2"
actx2 = repo[b'.']
repo.wwrite(b'bar-m', b'bar-m\n', b'')
repo.wwrite(b'bar-r', b'bar-r\n', b'')
repo[None].add([b'bar-m', b'bar-r'])
repo.commit(text=b'add bar-m, bar-r', date=b"0 0")
# ancestor "wcctx ~ 1"
actx1 = repo[b'.']
repo.wwrite(b'bar-m', b'bar-m bar-m\n', b'')
repo.wwrite(b'bar-a', b'bar-a\n', b'')
repo[None].add([b'bar-a'])
repo[None].forget([b'bar-r'])
# status at this point:
# M bar-m
# A bar-a
# R bar-r
# C foo
from mercurial import scmutil
print('== checking workingctx.status:')
wctx = repo[None]
print('wctx._status=%s' % (str(wctx._status)))
print('=== with "pattern match":')
print(actx1.status(other=wctx,
match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wctx._status=%s' % (str(wctx._status)))
print(actx2.status(other=wctx,
match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wctx._status=%s' % (str(wctx._status)))
print('=== with "always match" and "listclean=True":')
print(actx1.status(other=wctx, listclean=True))
print('wctx._status=%s' % (str(wctx._status)))
print(actx2.status(other=wctx, listclean=True))
print('wctx._status=%s' % (str(wctx._status)))
print("== checking workingcommitctx.status:")
wcctx = context.workingcommitctx(repo,
scmutil.status([b'bar-m'],
[b'bar-a'],
[],
[], [], [], []),
text=b'', date=b'0 0')
print('wcctx._status=%s' % (str(wcctx._status)))
print('=== with "always match":')
print(actx1.status(other=wcctx))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx))
print('wcctx._status=%s' % (str(wcctx._status)))
print('=== with "always match" and "listclean=True":')
print(actx1.status(other=wcctx, listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx, listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))
print('=== with "pattern match":')
print(actx1.status(other=wcctx,
match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx,
match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wcctx._status=%s' % (str(wcctx._status)))
print('=== with "pattern match" and "listclean=True":')
print(actx1.status(other=wcctx,
match=scmutil.matchfiles(repo, [b'bar-r', b'foo']),
listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx,
match=scmutil.matchfiles(repo, [b'bar-r', b'foo']),
listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))
os.chdir('..')
# test manifestlog being changed
print('== commit with manifestlog invalidated')
repo = hg.repository(u, b'test2', create=1)
os.chdir('test2')
# make some commits
for i in [b'1', b'2', b'3']:
with open(i, 'wb') as f:
f.write(i)
status = scmutil.status([], [i], [], [], [], [], [])
ctx = context.workingcommitctx(repo, status, text=i, user=b'test@test.com',
date=(0, 0))
ctx.p1().manifest() # side effect: cache manifestctx
n = repo.commitctx(ctx)
printb(b'commit %s: %s' % (i, hex(n)))
# touch 00manifest.i mtime so storecache could expire.
# repo.__dict__['manifestlog'] is deleted by transaction releasefn.
st = repo.svfs.stat(b'00manifest.i')
repo.svfs.utime(b'00manifest.i',
(st[stat.ST_MTIME] + 1, st[stat.ST_MTIME] + 1))
# read the file just committed
try:
if repo[n][i].data() != i:
print('data mismatch')
except Exception as ex:
print('cannot read data: %r' % ex)
with repo.wlock(), repo.lock(), repo.transaction(b'test'):
with open(b'4', 'wb') as f:
f.write(b'4')
repo.dirstate.normal(b'4')
repo.commit(b'4')
revsbefore = len(repo.changelog)
repo.invalidate(clearfilecache=True)
revsafter = len(repo.changelog)
if revsbefore != revsafter:
print('changeset lost by repo.invalidate()')