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 repobundlerepo
$ cat <<EOF >> $HGRCPATH
> [extensions]
> mq=
> [alias]
> tlog = log --template "{rev}: {node|short} {desc}\\n"
> theads = heads --template "{rev}: {desc}\\n"
> tincoming = incoming --template "{rev}: {desc}\\n"
> EOF
Setup main:
$ hg init base
$ cd base
$ echo "One" > one
$ hg add
adding one
$ hg ci -m "main: one added"
$ echo "++" >> one
$ hg ci -m "main: one updated"
Bundle main:
$ hg bundle --base=null ../main.hg
2 changesets found
$ cd ..
Incoming to fresh repo:
$ hg init fresh
$ hg -R fresh tincoming main.hg
comparing with main.hg
0: main: one added
1: main: one updated
$ test -f ./fresh/.hg/hg-bundle* && echo 'temp. bundle file remained' || true
$ hg -R fresh tincoming bundle:fresh+main.hg
comparing with bundle:fresh+main.hg
0: main: one added
1: main: one updated
Setup queue:
$ cd base
$ hg qinit -c
$ hg qnew -m "patch: two added" two.patch
$ echo two > two
$ hg add
adding two
$ hg qrefresh
$ hg qcommit -m "queue: two.patch added"
$ hg qpop -a
popping two.patch
patch queue now empty
Bundle queue:
$ hg -R .hg/patches bundle --base=null ../queue.hgq
1 changesets found
$ test -f ./fresh/.hg/hg-bundle* && echo 'temp. bundle file remained' || true
$ cd ..
Clone base:
$ hg clone base copy
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd copy
$ hg qinit -c
Incoming queue bundle:
$ hg -R .hg/patches tincoming ../queue.hgq
comparing with ../queue.hgq
0: queue: two.patch added
$ test -f .hg/hg-bundle* && echo 'temp. bundle file remained' || true
Pull queue bundle:
$ hg -R .hg/patches pull --update ../queue.hgq
pulling from ../queue.hgq
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 3 changes to 3 files
new changesets d7553909353d (1 drafts)
merging series
2 files updated, 1 files merged, 0 files removed, 0 files unresolved
$ test -f .hg/patches/hg-bundle* && echo 'temp. bundle file remained' || true
$ hg -R .hg/patches theads
0: queue: two.patch added
$ hg -R .hg/patches tlog
0: d7553909353d queue: two.patch added
$ hg qseries
two.patch
$ cd ..
Clone base again:
$ hg clone base copy2
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd copy2
$ hg qinit -c
Unbundle queue bundle:
$ hg -R .hg/patches unbundle --update ../queue.hgq
adding changesets
adding manifests
adding file changes
added 1 changesets with 3 changes to 3 files
new changesets d7553909353d (1 drafts)
merging series
2 files updated, 1 files merged, 0 files removed, 0 files unresolved
$ hg -R .hg/patches theads
0: queue: two.patch added
$ hg -R .hg/patches tlog
0: d7553909353d queue: two.patch added
$ hg qseries
two.patch
$ cd ..