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.
$ . "$TESTDIR/narrow-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [narrow]
> serveellipses=True
> EOF
$ for x in `$TESTDIR/seq.py 10`
> do
> echo $x > "f$x"
> hg add "f$x"
> hg commit -m "Commit f$x"
> done
$ cd ..
narrow clone a couple files, f2 and f8
$ hg clone --narrow ssh://user@dummy/master narrow --include "f2" --include "f8"
requesting all changes
adding changesets
adding manifests
adding file changes
added 5 changesets with 2 changes to 2 files
new changesets *:* (glob)
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd narrow
$ ls -A
.hg
f2
f8
$ cat f2 f8
2
8
$ cd ..
change every upstream file twice
$ cd master
$ for x in `$TESTDIR/seq.py 10`
> do
> echo "update#1 $x" >> "f$x"
> hg commit -m "Update#1 to f$x" "f$x"
> done
$ for x in `$TESTDIR/seq.py 10`
> do
> echo "update#2 $x" >> "f$x"
> hg commit -m "Update#2 to f$x" "f$x"
> done
$ cd ..
look for incoming changes
$ cd narrow
$ hg incoming --limit 3
comparing with ssh://user@dummy/master
searching for changes
changeset: 5:ddc055582556
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Update#1 to f1
changeset: 6:f66eb5ad621d
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Update#1 to f2
changeset: 7:c42ecff04e99
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Update#1 to f3
Interrupting the pull is safe
$ hg --config hooks.pretxnchangegroup.bad=false pull -q
transaction abort!
rollback completed
abort: pretxnchangegroup.bad hook exited with status 1
[40]
$ hg id
223311e70a6f tip
pull new changes down to the narrow clone. Should get 8 new changesets: 4
relevant to the narrow spec, and 4 ellipsis nodes gluing them all together.
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 9 changesets with 4 changes to 2 files
new changesets *:* (glob)
(run 'hg update' to get a working copy)
$ hg log -T '{rev}: {desc}\n'
13: Update#2 to f10
12: Update#2 to f8
11: Update#2 to f7
10: Update#2 to f2
9: Update#2 to f1
8: Update#1 to f8
7: Update#1 to f7
6: Update#1 to f2
5: Update#1 to f1
4: Commit f10
3: Commit f8
2: Commit f7
1: Commit f2
0: Commit f1
$ hg update tip
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
add a change and push it
$ echo "update#3 2" >> f2
$ hg commit -m "Update#3 to f2" f2
$ hg log f2 -T '{rev}: {desc}\n'
14: Update#3 to f2
10: Update#2 to f2
6: Update#1 to f2
1: Commit f2
$ hg push
pushing to ssh://user@dummy/master
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
$ cd ..
$ cd master
$ hg log f2 -T '{rev}: {desc}\n'
30: Update#3 to f2
21: Update#2 to f2
11: Update#1 to f2
1: Commit f2
$ hg log -l 3 -T '{rev}: {desc}\n'
30: Update#3 to f2
29: Update#2 to f10
28: Update#2 to f9
Can pull into repo with a single commit
$ cd ..
$ hg clone -q --narrow ssh://user@dummy/master narrow2 --include "f1" -r 0
$ cd narrow2
$ hg pull -q -r 1
remote: abort: unexpected error: unable to resolve parent while packing '00manifest' 1 for changeset 0
transaction abort!
rollback completed
abort: pull failed on remote
[100]