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 behavior of propertycache and unfiltered propertycache
The repoview overlay is quite complex. We test the behavior of
property cache of both localrepo and repoview to prevent
regression."""
import os
import subprocess
from mercurial import (
hg,
localrepo,
pycompat,
ui as uimod,
util,
)
from mercurial.utils import procutil
# create some special property cache that trace they call
calllog = []
@util.propertycache
def testcachedfoobar(repo):
name = repo.filtername
if name is None:
name = ''
val = len(name)
calllog.append(val)
return val
unficalllog = []
@localrepo.unfilteredpropertycache
def testcachedunfifoobar(repo):
name = repo.filtername
if name is None:
name = ''
val = 100 + len(name)
unficalllog.append(val)
return val
# plug them on repo
localrepo.localrepository.testcachedfoobar = testcachedfoobar
localrepo.localrepository.testcachedunfifoobar = testcachedunfifoobar
# Create an empty repo and instantiate it. It is important to run
# these tests on the real object to detect regression.
repopath = pycompat.fsencode(os.path.join(os.environ['TESTTMP'], 'repo'))
assert (
subprocess.call(
pycompat.rapply(procutil.tonativestr, [b'hg', b'init', repopath])
)
== 0
)
ui = uimod.ui.load()
repo = hg.repository(ui, path=repopath).unfiltered()
print('')
print('=== property cache ===')
print('')
print('calllog:', calllog)
print(
'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print('')
print('= first access on unfiltered, should do a call')
print('access:', repo.testcachedfoobar)
print('calllog:', calllog)
print(
'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print('')
print('= second access on unfiltered, should not do call')
print('access', repo.testcachedfoobar)
print('calllog:', calllog)
print(
'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print('')
print('= first access on "visible" view, should do a call')
visibleview = repo.filtered('visible')
print(
'cached value ("visible" view):',
vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print(
'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print(
'cached value ("visible" view):',
vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)
print('')
print('= second access on "visible view", should not do call')
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print(
'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print(
'cached value ("visible" view):',
vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)
print('')
print('= no effect on other view')
immutableview = repo.filtered('immutable')
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedfoobar', 'NOCACHE'),
)
print('access:', immutableview.testcachedfoobar)
print('calllog:', calllog)
print(
'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print(
'cached value ("visible" view):',
vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedfoobar', 'NOCACHE'),
)
# unfiltered property cache test
print('')
print('')
print('=== unfiltered property cache ===')
print('')
print('unficalllog:', unficalllog)
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("visible" view): ',
vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('')
print('= first access on unfiltered, should do a call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print('')
print('= second access on unfiltered, should not do call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print('')
print('= access on view should use the unfiltered cache')
print('access (unfiltered): ', repo.testcachedunfifoobar)
print('access ("visible" view): ', visibleview.testcachedunfifoobar)
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("visible" view): ',
vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('')
print('= even if we clear the unfiltered cache')
del repo.__dict__['testcachedunfifoobar']
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("visible" view): ',
vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('unficalllog:', unficalllog)
print('access ("visible" view): ', visibleview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("visible" view): ',
vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("visible" view): ',
vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('access (unfiltered): ', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
'cached value (unfiltered): ',
vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("visible" view): ',
vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
'cached value ("immutable" view):',
vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)