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.
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
Set up an extension to make sure remotefilelog clientsetup() runs
unconditionally even if we have never used a local shallow repo.
This mimics behavior when using remotefilelog with chg. clientsetup() can be
triggered due to a shallow repo, and then the code can later interact with
non-shallow repositories.
$ cat > setupremotefilelog.py << EOF
> from mercurial import extensions
> def extsetup(ui):
> remotefilelog = extensions.find(b'remotefilelog')
> remotefilelog.onetimeclientsetup(ui)
> EOF
Set up the master repository to pull from.
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ hg commit -qAm x
$ cd ..
$ hg clone ssh://user@dummy/master child -q
We should see the remotefilelog capability here, which advertises that
the server supports our custom getfiles method.
$ cd master
$ echo 'hello' | hg -R . serve --stdio | grep capa | identifyrflcaps
exp-remotefilelog-ssh-getfiles-1
x_rfl_getfile
x_rfl_getflogheads
$ echo 'capabilities' | hg -R . serve --stdio | identifyrflcaps ; echo
exp-remotefilelog-ssh-getfiles-1
x_rfl_getfile
x_rfl_getflogheads
Pull to the child repository. Use our custom setupremotefilelog extension
to ensure that remotefilelog.onetimeclientsetup() gets triggered. (Without
using chg it normally would not be run in this case since the local repository
is not shallow.)
$ echo y > y
$ hg commit -qAm y
$ cd ../child
$ hg pull --config extensions.setuprfl=$TESTTMP/setupremotefilelog.py
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets d34c38483be9
(run 'hg update' to get a working copy)
$ hg up
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat y
y
Test that bundle works in a non-remotefilelog repo w/ remotefilelog loaded
$ echo y >> y
$ hg commit -qAm "modify y"
$ hg bundle --base ".^" --rev . mybundle.hg --config extensions.setuprfl=$TESTTMP/setupremotefilelog.py
1 changesets found
$ cd ..