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 unittest
from mercurial import error, mdiff
from mercurial.utils import stringutil
# for readability, line numbers are 0-origin
text1 = b'''
00 at OLD
01 at OLD
02 at OLD
02 at NEW, 03 at OLD
03 at NEW, 04 at OLD
04 at NEW, 05 at OLD
05 at NEW, 06 at OLD
07 at OLD
08 at OLD
09 at OLD
10 at OLD
11 at OLD
'''[
1:
] # strip initial LF
text2 = b'''
00 at NEW
01 at NEW
02 at NEW, 03 at OLD
03 at NEW, 04 at OLD
04 at NEW, 05 at OLD
05 at NEW, 06 at OLD
06 at NEW
07 at NEW
08 at NEW
09 at NEW
10 at NEW
11 at NEW
'''[
1:
] # strip initial LF
def filteredblocks(blocks, rangeb):
"""return `rangea` extracted from `blocks` coming from
`mdiff.blocksinrange` along with the mask of blocks within rangeb.
"""
filtered, rangea = mdiff.blocksinrange(blocks, rangeb)
skipped = [b not in filtered for b in blocks]
return rangea, skipped
class blocksinrangetests(unittest.TestCase):
def setUp(self):
self.blocks = list(mdiff.allblocks(text1, text2))
assert self.blocks == [
([0, 3, 0, 2], b'!'),
((3, 7, 2, 6), b'='),
([7, 12, 6, 12], b'!'),
((12, 12, 12, 12), b'='),
], self.blocks
def testWithinEqual(self):
"""linerange within an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^
linerange2 = (3, 5)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (4, 6))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualStrictly(self):
"""linerange matching exactly an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^
linerange2 = (2, 6)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (3, 7))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualLowerbound(self):
"""linerange at beginning of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^
linerange2 = (2, 4)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (3, 5))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualLowerboundOneline(self):
"""oneline-linerange at beginning of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
linerange2 = (2, 3)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (3, 4))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualUpperbound(self):
"""linerange at end of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^
linerange2 = (3, 6)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (4, 7))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualUpperboundOneLine(self):
"""oneline-linerange at end of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
linerange2 = (5, 6)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (6, 7))
self.assertEqual(skipped, [True, False, True, True])
def testWithinFirstBlockNeq(self):
"""linerange within the first "!" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
# | (empty)
# ^
# ^^
for linerange2 in [
(0, 1),
(1, 1),
(1, 2),
(0, 2),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (0, 3))
self.assertEqual(skipped, [False, True, True, True])
def testWithinLastBlockNeq(self):
"""linerange within the last "!" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
# ^
# | (empty)
# ^^^^^^
# ^
for linerange2 in [
(6, 7),
(7, 8),
(7, 7),
(6, 12),
(11, 12),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (7, 12))
self.assertEqual(skipped, [True, True, False, True])
def testAccrossTwoBlocks(self):
"""linerange accross two blocks"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^
linerange2 = (1, 5)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (0, 6))
self.assertEqual(skipped, [False, False, True, True])
def testCrossingSeveralBlocks(self):
"""linerange accross three blocks"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^^^^
linerange2 = (1, 8)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (0, 12))
self.assertEqual(skipped, [False, False, False, True])
def testStartInEqBlock(self):
"""linerange starting in an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^
# ^^^^^^^
for linerange2, expectedlinerange1 in [
((5, 9), (6, 12)),
((4, 11), (5, 12)),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, expectedlinerange1)
self.assertEqual(skipped, [True, False, False, True])
def testEndInEqBlock(self):
"""linerange ending in an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^
# ^^^^^
for linerange2, expectedlinerange1 in [
((1, 3), (0, 4)),
((0, 4), (0, 5)),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, expectedlinerange1)
self.assertEqual(skipped, [False, False, True, True])
def testOutOfRange(self):
"""linerange exceeding file size"""
exctype = error.Abort
for linerange2 in [
(0, 34),
(15, 12),
]:
# Could be `with self.assertRaises(error.Abort)` but python2.6
# does not have assertRaises context manager.
try:
mdiff.blocksinrange(self.blocks, linerange2)
except exctype as exc:
self.assertTrue(
b'line range exceeds file size'
in stringutil.forcebytestr(exc)
)
else:
self.fail('%s not raised' % exctype.__name__)
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)