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.
"""test line matching with some failing examples and some which warn
run-test.t only checks positive matches and can not see warnings
(both by design)
"""
import doctest
import os
import re
# this is hack to make sure no escape characters are inserted into the output
if 'TERM' in os.environ:
del os.environ['TERM']
run_tests = __import__('run-tests')
def prn(ex):
m = ex.args[0]
if isinstance(m, str):
print(m)
else:
print(m.decode('utf-8'))
def lm(expected, output):
r"""check if output matches expected
does it generally work?
>>> lm(b'H*e (glob)\n', b'Here\n')
True
fail on bad test data
>>> try: lm(b'a\n',b'a')
... except AssertionError as ex: print(ex)
missing newline
>>> try: lm(b'single backslash\n', b'single \backslash\n')
... except AssertionError as ex: prn(ex)
single backslash or unknown char
"""
assert expected.endswith(b'\n') and output.endswith(
b'\n'
), 'missing newline'
assert not re.search(
br'[^ \w\\/\r\n()*?]', expected + output
), b'single backslash or unknown char'
test = run_tests.TTest(b'test-run-test.t', b'.', b'.')
match, exact = test.linematch(expected, output)
if isinstance(match, str):
return 'special: ' + match
elif isinstance(match, bytes):
return 'special: ' + match.decode('utf-8')
else:
return bool(match) # do not return match object
def wintests():
r"""test matching like running on windows
enable windows matching on any os
>>> _osaltsep = os.altsep
>>> os.altsep = True
>>> _osname = os.name
>>> os.name = 'nt'
>>> _old_windows = run_tests.WINDOWS
>>> run_tests.WINDOWS = True
valid match on windows
>>> lm(b'g/a*/d (glob)\n', b'g\\abc/d\n')
True
direct matching, glob unnecessary
>>> lm(b'g/b (glob)\n', b'g/b\n')
'special: -glob'
missing glob
>>> lm(b'/g/c/d/fg\n', b'\\g\\c\\d/fg\n')
True
>>> lm(b'/g/c/d/fg\n', b'\\g\\c\\d\\fg\r\n')
True
restore os.altsep
>>> os.altsep = _osaltsep
>>> os.name = _osname
>>> run_tests.WINDOWS = _old_windows
"""
pass
def otherostests():
r"""test matching like running on non-windows os
disable windows matching on any os
>>> _osaltsep = os.altsep
>>> os.altsep = False
>>> _osname = os.name
>>> os.name = 'nt'
backslash does not match slash
>>> lm(b'h/a* (glob)\n', b'h\\ab\n')
False
direct matching glob can not be recognized
>>> lm(b'h/b (glob)\n', b'h/b\n')
True
missing glob can not not be recognized
>>> lm(b'/h/c/df/g/\n', b'\\h/c\\df/g\\\n')
False
restore os.altsep
>>> os.altsep = _osaltsep
>>> os.name = _osname
"""
pass
if __name__ == '__main__':
doctest.testmod()