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 p4
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert = " >> $HGRCPATH
create p4 depot
$ P4ROOT=`pwd`/depot; export P4ROOT
$ P4AUDIT=$P4ROOT/audit; export P4AUDIT
$ P4JOURNAL=$P4ROOT/journal; export P4JOURNAL
$ P4LOG=$P4ROOT/log; export P4LOG
$ P4PORT=localhost:$HGPORT; export P4PORT
$ P4DEBUG=1; export P4DEBUG
start the p4 server
$ [ ! -d $P4ROOT ] && mkdir $P4ROOT
$ p4d -f -J off >$P4ROOT/stdout 2>$P4ROOT/stderr &
$ echo $! >> $DAEMON_PIDS
$ trap "echo stopping the p4 server ; p4 admin stop" EXIT
$ # wait for the server to initialize
$ while ! p4 ; do
> sleep 1
> done >/dev/null 2>/dev/null
create a client spec
$ P4CLIENT=hg-p4-import; export P4CLIENT
$ DEPOTPATH=//depot/test-mercurial-import/...
$ p4 client -o | sed '/^View:/,$ d' >p4client
$ echo View: >>p4client
$ echo " $DEPOTPATH //$P4CLIENT/..." >>p4client
$ p4 client -i <p4client
Client hg-p4-import saved.
populate the depot
$ echo a > a
$ mkdir b
$ echo c > b/c
$ p4 add a b/c
//depot/test-mercurial-import/a#1 - opened for add
//depot/test-mercurial-import/b/c#1 - opened for add
$ p4 submit -d initial
Submitting change 1.
Locking 2 files ...
add //depot/test-mercurial-import/a#1
add //depot/test-mercurial-import/b/c#1
Change 1 submitted.
change some files
$ p4 edit a
//depot/test-mercurial-import/a#1 - opened for edit
$ echo aa >> a
$ p4 submit -d "change a"
Submitting change 2.
Locking 1 files ...
edit //depot/test-mercurial-import/a#2
Change 2 submitted.
$ p4 edit b/c
//depot/test-mercurial-import/b/c#1 - opened for edit
$ echo cc >> b/c
$ p4 submit -d "change b/c"
Submitting change 3.
Locking 1 files ...
edit //depot/test-mercurial-import/b/c#2
Change 3 submitted.
convert
$ hg convert -s p4 $DEPOTPATH dst
initializing destination dst repository
scanning source...
reading p4 views
collecting p4 changelists
1 initial
2 change a
3 change b/c
sorting...
converting...
2 initial
1 change a
0 change b/c
$ hg -R dst log --template 'rev={rev} desc="{desc}" tags="{tags}" files="{files}"\n'
rev=2 desc="change b/c" tags="tip" files="b/c"
rev=1 desc="change a" tags="" files="a"
rev=0 desc="initial" tags="" files="a b/c"
change some files
$ p4 edit a b/c
//depot/test-mercurial-import/a#2 - opened for edit
//depot/test-mercurial-import/b/c#2 - opened for edit
$ echo aaa >> a
$ echo ccc >> b/c
$ p4 submit -d "change a b/c"
Submitting change 4.
Locking 2 files ...
edit //depot/test-mercurial-import/a#3
edit //depot/test-mercurial-import/b/c#3
Change 4 submitted.
convert again
$ hg convert -s p4 $DEPOTPATH dst
scanning source...
reading p4 views
collecting p4 changelists
4 change a b/c
sorting...
converting...
0 change a b/c
$ hg -R dst log --template 'rev={rev} desc="{desc}" tags="{tags}" files="{files}"\n'
rev=3 desc="change a b/c" tags="tip" files="a b/c"
rev=2 desc="change b/c" tags="" files="b/c"
rev=1 desc="change a" tags="" files="a"
rev=0 desc="initial" tags="" files="a b/c"
interesting names
$ echo dddd > "d d"
$ mkdir " e"
$ echo fff >" e/ f"
$ p4 add "d d" " e/ f"
//depot/test-mercurial-import/d d#1 - opened for add
//depot/test-mercurial-import/ e/ f#1 - opened for add
$ p4 submit -d "add d e f"
Submitting change 5.
Locking 2 files ...
add //depot/test-mercurial-import/ e/ f#1
add //depot/test-mercurial-import/d d#1
Change 5 submitted.
convert again
$ hg convert -s p4 $DEPOTPATH dst
scanning source...
reading p4 views
collecting p4 changelists
5 add d e f
sorting...
converting...
0 add d e f
$ hg -R dst log --template 'rev={rev} desc="{desc}" tags="{tags}" files="{files}"\n'
rev=4 desc="add d e f" tags="tip" files=" e/ f d d"
rev=3 desc="change a b/c" tags="" files="a b/c"
rev=2 desc="change b/c" tags="" files="b/c"
rev=1 desc="change a" tags="" files="a"
rev=0 desc="initial" tags="" files="a b/c"
empty commit message
$ p4 edit a
//depot/test-mercurial-import/a#3 - opened for edit
$ echo aaaaa >> a
$ p4 submit -d ""
Submitting change 6.
Locking 1 files ...
edit //depot/test-mercurial-import/a#4
Change 6 submitted.
$ hg convert -s p4 $DEPOTPATH dst
scanning source...
reading p4 views
collecting p4 changelists
6 **empty changelist description**
sorting...
converting...
0
exit trap:
stopping the p4 server