localrepo: create new function for instantiating a local repo object
Today, there is a single local repository class - localrepository. Its
__init__ is responsible for loading the .hg/requires file and taking
different actions depending on what is present.
In addition, extensions may define a "reposetup" function that
monkeypatches constructed repository instances, often by implementing
a derived type and changing the __class__ of the repo instance.
Work around alternate storage backends and partial clone has made it
clear to me that shoehorning all this logic into __init__ and operating
on an existing instance is too convoluted. For example, localrepository
assumes revlog storage and swapping in non-revlog storage requires
overriding e.g. file() to return something that isn't a revlog. I've
authored various patches that either:
a) teach various methods (like file()) about different states and
taking the appropriate code path at run-time
b) create methods/attributes/callables used for instantiating things
and populating these in __init__
"a" incurs run-time performance penalties and makes code more
complicated since various functions have a bunch of "if storage is X"
branches.
"b" makes localrepository quickly explode in complexity.
My plan for tackling this problem is to make the local repository type
more dynamic. Instead of a static localrepository class/type that
supports all of the local repository configurations (revlogs vs other,
revlogs with ellipsis, revlog v1 versus revlog v2, etc), we'll
dynamically construct a type providing the implementations that are
needed for the repository on disk, derived from the .hg/requires file
and configuration options. The constructed repository type will be
specialized and methods won't need to be taught about different
implementations nor overloaded.
We may also leverage this functionality for building types that don't
implement all attributes. For example, the "intents" feature allows
commands to declare that they are read only. By dynamically
constructing a repository type, we could return a repository instance
with no attributes related to mutating the repository. This could
include things like a "changelog" property implementation that doesn't
check whether it needs to invalidate the hidden revisions set on every
access.
This commit establishes a function for building a local repository
instance. Future commits will start moving functionality from
localrepository.__init__ to this function. Then we'll start dynamically
changing the returned type depending on options that are present.
This change may seem radical. But it should be fully compatible with
the reposetup() model - at least for now.
Differential Revision: https://phab.mercurial-scm.org/D4563
from __future__ import absolute_import, print_function
import itertools
from mercurial import pycompat
from hgext import absorb
class simplefctx(object):
def __init__(self, content):
self.content = content
def data(self):
return self.content
def insertreturns(x):
# insert "\n"s after each single char
if isinstance(x, bytes):
return b''.join(ch + b'\n' for ch in pycompat.bytestr(x))
else:
return pycompat.maplist(insertreturns, x)
def removereturns(x):
# the revert of "insertreturns"
if isinstance(x, bytes):
return x.replace(b'\n', b'')
else:
return pycompat.maplist(removereturns, x)
def assertlistequal(lhs, rhs, decorator=lambda x: x):
if lhs != rhs:
raise RuntimeError('mismatch:\n actual: %r\n expected: %r'
% tuple(map(decorator, [lhs, rhs])))
def testfilefixup(oldcontents, workingcopy, expectedcontents, fixups=None):
"""([str], str, [str], [(rev, a1, a2, b1, b2)]?) -> None
workingcopy is a string, of which every character denotes a single line.
oldcontents, expectedcontents are lists of strings, every character of
every string denots a single line.
if fixups is not None, it's the expected fixups list and will be checked.
"""
expectedcontents = insertreturns(expectedcontents)
oldcontents = insertreturns(oldcontents)
workingcopy = insertreturns(workingcopy)
state = absorb.filefixupstate(pycompat.maplist(simplefctx, oldcontents))
state.diffwith(simplefctx(workingcopy))
if fixups is not None:
assertlistequal(state.fixups, fixups)
state.apply()
assertlistequal(state.finalcontents, expectedcontents, removereturns)
def buildcontents(linesrevs):
# linesrevs: [(linecontent : str, revs : [int])]
revs = set(itertools.chain(*[revs for line, revs in linesrevs]))
return [b''] + [
b''.join([l for l, rs in linesrevs if r in rs])
for r in sorted(revs)
]
# input case 0: one single commit
case0 = [b'', b'11']
# replace a single chunk
testfilefixup(case0, b'', [b'', b''])
testfilefixup(case0, b'2', [b'', b'2'])
testfilefixup(case0, b'22', [b'', b'22'])
testfilefixup(case0, b'222', [b'', b'222'])
# input case 1: 3 lines, each commit adds one line
case1 = buildcontents([
(b'1', [1, 2, 3]),
(b'2', [ 2, 3]),
(b'3', [ 3]),
])
# 1:1 line mapping
testfilefixup(case1, b'123', case1)
testfilefixup(case1, b'12c', [b'', b'1', b'12', b'12c'])
testfilefixup(case1, b'1b3', [b'', b'1', b'1b', b'1b3'])
testfilefixup(case1, b'1bc', [b'', b'1', b'1b', b'1bc'])
testfilefixup(case1, b'a23', [b'', b'a', b'a2', b'a23'])
testfilefixup(case1, b'a2c', [b'', b'a', b'a2', b'a2c'])
testfilefixup(case1, b'ab3', [b'', b'a', b'ab', b'ab3'])
testfilefixup(case1, b'abc', [b'', b'a', b'ab', b'abc'])
# non 1:1 edits
testfilefixup(case1, b'abcd', case1)
testfilefixup(case1, b'ab', case1)
# deletion
testfilefixup(case1, b'', [b'', b'', b'', b''])
testfilefixup(case1, b'1', [b'', b'1', b'1', b'1'])
testfilefixup(case1, b'2', [b'', b'', b'2', b'2'])
testfilefixup(case1, b'3', [b'', b'', b'', b'3'])
testfilefixup(case1, b'13', [b'', b'1', b'1', b'13'])
# replaces
testfilefixup(case1, b'1bb3', [b'', b'1', b'1bb', b'1bb3'])
# (confusing) replaces
testfilefixup(case1, b'1bbb', case1)
testfilefixup(case1, b'bbbb', case1)
testfilefixup(case1, b'bbb3', case1)
testfilefixup(case1, b'1b', case1)
testfilefixup(case1, b'bb', case1)
testfilefixup(case1, b'b3', case1)
# insertions at the beginning and the end
testfilefixup(case1, b'123c', [b'', b'1', b'12', b'123c'])
testfilefixup(case1, b'a123', [b'', b'a1', b'a12', b'a123'])
# (confusing) insertions
testfilefixup(case1, b'1a23', case1)
testfilefixup(case1, b'12b3', case1)
# input case 2: delete in the middle
case2 = buildcontents([
(b'11', [1, 2]),
(b'22', [1 ]),
(b'33', [1, 2]),
])
# deletion (optimize code should make it 2 chunks)
testfilefixup(case2, b'', [b'', b'22', b''],
fixups=[(4, 0, 2, 0, 0), (4, 2, 4, 0, 0)])
# 1:1 line mapping
testfilefixup(case2, b'aaaa', [b'', b'aa22aa', b'aaaa'])
# non 1:1 edits
# note: unlike case0, the chunk is not "continuous" and no edit allowed
testfilefixup(case2, b'aaa', case2)
# input case 3: rev 3 reverts rev 2
case3 = buildcontents([
(b'1', [1, 2, 3]),
(b'2', [ 2 ]),
(b'3', [1, 2, 3]),
])
# 1:1 line mapping
testfilefixup(case3, b'13', case3)
testfilefixup(case3, b'1b', [b'', b'1b', b'12b', b'1b'])
testfilefixup(case3, b'a3', [b'', b'a3', b'a23', b'a3'])
testfilefixup(case3, b'ab', [b'', b'ab', b'a2b', b'ab'])
# non 1:1 edits
testfilefixup(case3, b'a', case3)
testfilefixup(case3, b'abc', case3)
# deletion
testfilefixup(case3, b'', [b'', b'', b'2', b''])
# insertion
testfilefixup(case3, b'a13c', [b'', b'a13c', b'a123c', b'a13c'])
# input case 4: a slightly complex case
case4 = buildcontents([
(b'1', [1, 2, 3]),
(b'2', [ 2, 3]),
(b'3', [1, 2, ]),
(b'4', [1, 3]),
(b'5', [ 3]),
(b'6', [ 2, 3]),
(b'7', [ 2 ]),
(b'8', [ 2, 3]),
(b'9', [ 3]),
])
testfilefixup(case4, b'1245689', case4)
testfilefixup(case4, b'1a2456bbb', case4)
testfilefixup(case4, b'1abc5689', case4)
testfilefixup(case4, b'1ab5689', [b'', b'134', b'1a3678', b'1ab5689'])
testfilefixup(case4, b'aa2bcd8ee', [b'', b'aa34', b'aa23d78', b'aa2bcd8ee'])
testfilefixup(case4, b'aa2bcdd8ee',[b'', b'aa34', b'aa23678', b'aa24568ee'])
testfilefixup(case4, b'aaaaaa', case4)
testfilefixup(case4, b'aa258b', [b'', b'aa34', b'aa2378', b'aa258b'])
testfilefixup(case4, b'25bb', [b'', b'34', b'23678', b'25689'])
testfilefixup(case4, b'27', [b'', b'34', b'23678', b'245689'])
testfilefixup(case4, b'28', [b'', b'34', b'2378', b'28'])
testfilefixup(case4, b'', [b'', b'34', b'37', b''])
# input case 5: replace a small chunk which is near a deleted line
case5 = buildcontents([
(b'12', [1, 2]),
(b'3', [1]),
(b'4', [1, 2]),
])
testfilefixup(case5, b'1cd4', [b'', b'1cd34', b'1cd4'])
# input case 6: base "changeset" is immutable
case6 = [b'1357', b'0125678']
testfilefixup(case6, b'0125678', case6)
testfilefixup(case6, b'0a25678', case6)
testfilefixup(case6, b'0a256b8', case6)
testfilefixup(case6, b'abcdefg', [b'1357', b'a1c5e7g'])
testfilefixup(case6, b'abcdef', case6)
testfilefixup(case6, b'', [b'1357', b'157'])
testfilefixup(case6, b'0123456789', [b'1357', b'0123456789'])
# input case 7: change an empty file
case7 = [b'']
testfilefixup(case7, b'1', case7)