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 cvs no-root
$ filterpath()
> {
> eval "$@" | sed "s:$CVSROOT:*REPO*:g"
> }
$ cvscall()
> {
> cvs -f "$@"
> }
output of 'cvs ci' varies unpredictably, so discard most of it
-- just keep the part that matters
$ cvsci()
> {
> cvs -f ci -f "$@" > /dev/null
> }
$ hgcat()
> {
> hg --cwd src-hg cat -r tip "$1"
> }
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert = " >> $HGRCPATH
create cvs repository
$ mkdir cvsmaster
$ cd cvsmaster
$ CVSROOT=`pwd`
$ export CVSROOT
$ CVS_OPTIONS=-f
$ export CVS_OPTIONS
$ cd ..
$ rmdir cvsmaster
$ filterpath cvscall -Q -d "$CVSROOT" init
checkout #1: add foo.txt
$ cvscall -Q checkout -d cvsworktmp .
$ cd cvsworktmp
$ mkdir foo
$ cvscall -Q add foo
$ cd foo
$ echo foo > foo.txt
$ cvscall -Q add foo.txt
$ cvsci -m "add foo.txt" foo.txt
$ cd ../..
$ rm -rf cvsworktmp
checkout #2: create MYBRANCH1 and modify foo.txt on it
$ cvscall -Q checkout -d cvswork foo
$ cd cvswork
$ cvscall -q rtag -b -R MYBRANCH1 foo
$ cvscall -Q update -P -r MYBRANCH1
$ echo bar > foo.txt
$ cvsci -m "bar" foo.txt
$ echo baz > foo.txt
$ cvsci -m "baz" foo.txt
create MYBRANCH1_2 and modify foo.txt some more
$ cvscall -q rtag -b -R -r MYBRANCH1 MYBRANCH1_2 foo
$ cvscall -Q update -P -r MYBRANCH1_2
$ echo bazzie > foo.txt
$ cvsci -m "bazzie" foo.txt
create MYBRANCH1_1 and modify foo.txt yet again
$ cvscall -q rtag -b -R MYBRANCH1_1 foo
$ cvscall -Q update -P -r MYBRANCH1_1
$ echo quux > foo.txt
$ cvsci -m "quux" foo.txt
merge MYBRANCH1 to MYBRANCH1_1
$ filterpath cvscall -Q update -P -jMYBRANCH1
rcsmerge: warning: conflicts during merge
RCS file: *REPO*/foo/foo.txt,v
retrieving revision 1.1
retrieving revision 1.1.2.2
Merging differences between 1.1 and 1.1.2.2 into foo.txt
carefully placed sleep to dodge cvs bug (optimization?) where it
sometimes ignores a "commit" command if it comes too fast (the -f
option in cvsci seems to work for all the other commits in this
script)
$ sleep 1
$ echo xyzzy > foo.txt
$ cvsci -m "merge1+clobber" foo.txt
#if unix-permissions
return to trunk and merge MYBRANCH1_2
$ cvscall -Q update -P -A
$ filterpath cvscall -Q update -P -jMYBRANCH1_2
RCS file: *REPO*/foo/foo.txt,v
retrieving revision 1.1
retrieving revision 1.1.2.2.2.1
Merging differences between 1.1 and 1.1.2.2.2.1 into foo.txt
$ cvsci -m "merge2" foo.txt
$ REALCVS=`which cvs`
$ echo "for x in \$*; do if [ \"\$x\" = \"rlog\" ]; then echo \"RCS file: $CVSROOT/foo/foo.txt,v\"; cat \"$TESTDIR/test-convert-cvsnt-mergepoints.rlog\"; exit 0; fi; done; $REALCVS \$*" > ../cvs
$ chmod +x ../cvs
$ PATH=..:${PATH} hg debugcvsps --parents foo
collecting CVS rlog
7 log entries
creating changesets
7 changeset entries
---------------------
PatchSet 1
Date: * (glob)
Author: user
Branch: HEAD
Tag: (none)
Branchpoints: MYBRANCH1, MYBRANCH1_1
Log:
foo.txt
Members:
foo.txt:INITIAL->1.1
---------------------
PatchSet 2
Date: * (glob)
Author: user
Branch: MYBRANCH1
Tag: (none)
Parent: 1
Log:
bar
Members:
foo.txt:1.1->1.1.2.1
---------------------
PatchSet 3
Date: * (glob)
Author: user
Branch: MYBRANCH1
Tag: (none)
Branchpoints: MYBRANCH1_2
Parent: 2
Log:
baz
Members:
foo.txt:1.1.2.1->1.1.2.2
---------------------
PatchSet 4
Date: * (glob)
Author: user
Branch: MYBRANCH1_1
Tag: (none)
Parent: 1
Log:
quux
Members:
foo.txt:1.1->1.1.4.1
---------------------
PatchSet 5
Date: * (glob)
Author: user
Branch: MYBRANCH1_2
Tag: (none)
Parent: 3
Log:
bazzie
Members:
foo.txt:1.1.2.2->1.1.2.2.2.1
---------------------
PatchSet 6
Date: * (glob)
Author: user
Branch: HEAD
Tag: (none)
Parents: 1,5
Log:
merge
Members:
foo.txt:1.1->1.2
---------------------
PatchSet 7
Date: * (glob)
Author: user
Branch: MYBRANCH1_1
Tag: (none)
Parents: 4,3
Log:
merge
Members:
foo.txt:1.1.4.1->1.1.4.2
#endif
$ cd ..