procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
import itertools
from mercurial import pycompat
from hgext import absorb
class simplefctx:
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), 'path'
)
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)