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 extension of unfinished states support.
$ mkdir chainify
$ cd chainify
$ cat >> chainify.py <<EOF
> from mercurial import cmdutil, error, extensions, exthelper, node, scmutil, state
> from hgext import rebase
>
> eh = exthelper.exthelper()
>
> extsetup = eh.finalextsetup
> cmdtable = eh.cmdtable
>
> # Rebase calls addunfinished in uisetup, so we have to call it in extsetup.
> # Ideally there'd by an 'extensions.afteruisetup()' just like
> # 'extensions.afterloaded()' to allow nesting multiple commands.
> @eh.extsetup
> def _extsetup(ui):
> state.addunfinished(
> b'chainify',
> b'chainify.state',
> continueflag=True,
> childopnames=[b'rebase'])
>
> def _node(repo, arg):
> return node.hex(scmutil.revsingle(repo, arg).node())
>
> @eh.command(
> b'chainify',
> [(b'r', b'revs', [], b'revs to chain', b'REV'),
> (b'', b'continue', False, b'continue op')],
> b'chainify [-r REV] +',
> inferrepo=True)
> def chainify(ui, repo, **opts):
> """Rebases r1, r2, r3, etc. into a chain."""
> with repo.wlock(), repo.lock():
> cmdstate = state.cmdstate(repo, b'chainify.state')
> if opts['continue']:
> if not cmdstate.exists():
> raise error.Abort(b'no chainify in progress')
> else:
> cmdutil.checkunfinished(repo)
> data = {
> b'tip': _node(repo, opts['revs'][0]),
> b'revs': b','.join(_node(repo, r) for r in opts['revs'][1:]),
> }
> cmdstate.save(1, data)
>
> data = cmdstate.read()
> while data[b'revs']:
> tip = data[b'tip']
> revs = data[b'revs'].split(b',')
> with state.delegating(repo, b'chainify', b'rebase'):
> ui.status(b'rebasing %s onto %s\n' % (revs[0][:12], tip[:12]))
> if state.ischildunfinished(repo, b'chainify', b'rebase'):
> rc = state.continuechild(ui, repo, b'chainify', b'rebase')
> else:
> rc = rebase.rebase(ui, repo, rev=[revs[0]], dest=tip)
> if rc and rc != 0:
> raise error.Abort(b'rebase failed (rc: %d)' % rc)
> data[b'tip'] = _node(repo, b'tip')
> data[b'revs'] = b','.join(revs[1:])
> cmdstate.save(1, data)
> cmdstate.delete()
> ui.status(b'done chainifying\n')
> EOF
$ chainifypath=`pwd`/chainify.py
$ echo '[extensions]' >> $HGRCPATH
$ echo "chainify = $chainifypath" >> $HGRCPATH
$ echo "rebase =" >> $HGRCPATH
$ cd $TESTTMP
$ hg init a
$ cd a
$ echo base > base.txt
$ hg commit -Aqm 'base commit'
$ echo foo > file1
$ hg commit -Aqm 'add file'
$ hg co -q ".^"
$ echo bar > file2
$ hg commit -Aqm 'add other file'
$ hg co -q ".^"
$ echo foo2 > file1
$ hg commit -Aqm 'add conflicting file'
$ hg co -q ".^"
$ hg log --graph --template '{rev} {files}'
o 3 file1
|
| o 2 file2
|/
| o 1 file1
|/
@ 0 base.txt
$ hg chainify -r 8430cfdf77c2 -r f8596309dff8 -r a858b338b3e9
rebasing f8596309dff8 onto 8430cfdf77c2
rebasing 2:f8596309dff8 "add other file"
saved backup bundle to $TESTTMP/* (glob)
rebasing a858b338b3e9 onto 83c722183a8e
rebasing 2:a858b338b3e9 "add conflicting file"
merging file1
warning: conflicts while merging file1! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg chainify --continue')
[240]
$ hg status --config commands.status.verbose=True
M file1
? file1.orig
# The repository is in an unfinished *chainify* state.
# Unresolved merge conflicts:
#
# file1
#
# To mark files as resolved: hg resolve --mark FILE
# To continue: hg chainify --continue
# To abort: hg chainify --abort
$ echo foo3 > file1
$ hg resolve --mark file1
(no more unresolved files)
continue: hg chainify --continue
$ hg chainify --continue
rebasing a858b338b3e9 onto 83c722183a8e
rebasing 2:a858b338b3e9 "add conflicting file"
saved backup bundle to $TESTTMP/* (glob)
done chainifying
$ hg log --graph --template '{rev} {files}'
o 3 file1
|
o 2 file2
|
o 1 file1
|
@ 0 base.txt