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.
Create a repository:
#if no-extraextensions
$ hg config
chgserver.idletimeout=60
devel.all-warnings=true
devel.default-date=0 0
extensions.fsmonitor= (fsmonitor !)
format.use-dirstate-v2=1 (dirstate-v2 !)
largefiles.usercache=$TESTTMP/.cache/largefiles
lfs.usercache=$TESTTMP/.cache/lfs
ui.slash=True
ui.interactive=False
ui.detailed-exit-code=True
ui.merge=internal:merge
ui.mergemarkers=detailed
ui.promptecho=True
ui.ssh=* (glob)
ui.timeout.warn=15
web.address=localhost
web\.ipv6=(?:True|False) (re)
web.server-header=testing stub value
#endif
$ hg init t
$ cd t
Prepare a changeset:
$ echo a > a
$ hg add a
$ hg status
A a
Writes to stdio succeed and fail appropriately
#if devfull
$ hg status 2>/dev/full
A a
$ hg status >/dev/full
abort: No space left on device* (glob)
[255]
#endif
#if devfull
$ hg status >/dev/full 2>&1
[255]
$ hg status ENOENT 2>/dev/full
[255]
#endif
On Python 3, stdio may be None:
$ hg debuguiprompt --config ui.interactive=true 0<&-
abort: Bad file descriptor (no-rhg !)
abort: response expected (rhg !)
[255]
$ hg version -q 0<&-
Mercurial Distributed SCM * (glob)
#if py3 no-rhg
$ hg version -q 1>&-
abort: Bad file descriptor
[255]
#else
$ hg version -q 1>&-
#endif
$ hg unknown -q 1>&-
hg: unknown command 'unknown'
(did you mean debugknown?)
[10]
$ hg version -q 2>&-
Mercurial Distributed SCM * (glob)
$ hg unknown -q 2>&-
[10]
$ hg commit -m test
This command is ancient:
$ hg history
changeset: 0:acb14030fe0a
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: test
Verify that updating to revision 0 via commands.update() works properly
$ cat <<EOF > update_to_rev0.py
> from mercurial import commands, hg, ui as uimod
> myui = uimod.ui.load()
> repo = hg.repository(myui, path=b'.')
> commands.update(myui, repo, rev=b"0")
> EOF
$ hg up null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ "$PYTHON" ./update_to_rev0.py
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg identify -n
0
Poke around at hashes:
$ hg manifest --debug
b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644 a
$ hg cat a
a
Verify should succeed:
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 1 changesets with 1 changes to 1 files
Repository root:
$ hg root
$TESTTMP/t
$ hg log -l1 -T '{reporoot}\n'
$TESTTMP/t
$ hg root -Tjson | sed 's|\\\\|\\|g'
[
{
"hgpath": "$TESTTMP/t/.hg",
"reporoot": "$TESTTMP/t",
"storepath": "$TESTTMP/t/.hg/store"
}
]
At the end...
$ cd ..
Status message redirection:
$ hg init empty
status messages are sent to stdout by default:
$ hg outgoing -R t empty -Tjson 2>/dev/null
comparing with empty
searching for changes
[
{
"bookmarks": [],
"branch": "default",
"date": [0, 0],
"desc": "test",
"node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
"parents": ["0000000000000000000000000000000000000000"],
"phase": "draft",
"rev": 0,
"tags": ["tip"],
"user": "test"
}
]
which can be configured to send to stderr, so the output wouldn't be
interleaved:
$ cat <<'EOF' >> "$HGRCPATH"
> [ui]
> message-output = stderr
> EOF
$ hg outgoing -R t empty -Tjson 2>/dev/null
[
{
"bookmarks": [],
"branch": "default",
"date": [0, 0],
"desc": "test",
"node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
"parents": ["0000000000000000000000000000000000000000"],
"phase": "draft",
"rev": 0,
"tags": ["tip"],
"user": "test"
}
]
$ hg outgoing -R t empty -Tjson >/dev/null
comparing with empty
searching for changes
this option should be turned off by HGPLAIN= since it may break scripting use:
$ HGPLAIN= hg outgoing -R t empty -Tjson 2>/dev/null
comparing with empty
searching for changes
[
{
"bookmarks": [],
"branch": "default",
"date": [0, 0],
"desc": "test",
"node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
"parents": ["0000000000000000000000000000000000000000"],
"phase": "draft",
"rev": 0,
"tags": ["tip"],
"user": "test"
}
]
but still overridden by --config:
$ HGPLAIN= hg outgoing -R t empty -Tjson --config ui.message-output=stderr \
> 2>/dev/null
[
{
"bookmarks": [],
"branch": "default",
"date": [0, 0],
"desc": "test",
"node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
"parents": ["0000000000000000000000000000000000000000"],
"phase": "draft",
"rev": 0,
"tags": ["tip"],
"user": "test"
}
]
Invalid ui.message-output option:
$ hg log -R t --config ui.message-output=bad
abort: invalid ui.message-output destination: bad
[255]
Underlying message streams should be updated when ui.fout/ferr are set:
$ cat <<'EOF' > capui.py
> import io
> from mercurial import registrar
> cmdtable = {}
> command = registrar.command(cmdtable)
> @command(b'capui', norepo=True)
> def capui(ui):
> out = ui.fout
> ui.fout = io.BytesIO()
> ui.status(b'status\n')
> ui.ferr = io.BytesIO()
> ui.warn(b'warn\n')
> out.write(b'stdout: %s' % ui.fout.getvalue())
> out.write(b'stderr: %s' % ui.ferr.getvalue())
> EOF
$ hg --config extensions.capui=capui.py --config ui.message-output=stdio capui
stdout: status
stderr: warn