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 tla symlink
$ tla my-id "mercurial <mercurial@mercurial-scm.org>"
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert=" >> $HGRCPATH
create tla archive
$ tla make-archive tla@mercurial--convert `pwd`/hg-test-convert-tla
initialize tla repo
$ mkdir tla-repo
$ cd tla-repo/
$ tla init-tree tla@mercurial--convert/tla--test--0
$ tla import
* creating version tla@mercurial--convert/tla--test--0
* imported tla@mercurial--convert/tla--test--0
create initial files
$ echo 'this is a file' > a
$ tla add a
$ mkdir src
$ tla add src
$ cd src
$ dd count=1 if=/dev/zero of=b > /dev/null 2> /dev/null
$ tla add b
$ tla commit -s "added a file, src and src/b (binary)"
A/ .arch-ids
A/ src
A/ src/.arch-ids
A .arch-ids/a.id
A a
A src/.arch-ids/=id
A src/.arch-ids/b.id
A src/b
* update pristine tree (tla@mercurial--convert/tla--test--0--base-0 => tla--test--0--patch-1)
* committed tla@mercurial--convert/tla--test--0--patch-1
create link file and modify a
$ ln -s ../a a-link
$ tla add a-link
$ echo 'this a modification to a' >> ../a
$ tla commit -s "added link to a and modify a"
A src/.arch-ids/a-link.id
A src/a-link
M a
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-1 => tla--test--0--patch-2)
* committed tla@mercurial--convert/tla--test--0--patch-2
create second link and modify b
$ ln -s ../a a-link-2
$ tla add a-link-2
$ dd count=1 seek=1 if=/dev/zero of=b > /dev/null 2> /dev/null
$ tla commit -s "added second link and modify b"
A src/.arch-ids/a-link-2.id
A src/a-link-2
Mb src/b
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-2 => tla--test--0--patch-3)
* committed tla@mercurial--convert/tla--test--0--patch-3
b file to link and a-link-2 to regular file
$ rm -f a-link-2
$ echo 'this is now a regular file' > a-link-2
$ ln -sf ../a b
$ tla commit -s "file to link and link to file test"
fl src/b
lf src/a-link-2
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-3 => tla--test--0--patch-4)
* committed tla@mercurial--convert/tla--test--0--patch-4
move a-link-2 file and src directory
$ cd ..
$ tla mv src/a-link-2 c
$ tla mv src test
$ tla commit -s "move and rename a-link-2 file and src directory"
D/ src/.arch-ids
A/ test/.arch-ids
/> src test
=> src/.arch-ids/a-link-2.id .arch-ids/c.id
=> src/a-link-2 c
=> src/.arch-ids/=id test/.arch-ids/=id
=> src/.arch-ids/a-link.id test/.arch-ids/a-link.id
=> src/.arch-ids/b.id test/.arch-ids/b.id
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-4 => tla--test--0--patch-5)
* committed tla@mercurial--convert/tla--test--0--patch-5
$ cd ..
converting tla repo to Mercurial
$ hg convert tla-repo tla-repo-hg
initializing destination tla-repo-hg repository
analyzing tree version tla@mercurial--convert/tla--test--0...
scanning source...
sorting...
converting...
5 initial import
4 added a file, src and src/b (binary)
3 added link to a and modify a
2 added second link and modify b
1 file to link and link to file test
0 move and rename a-link-2 file and src directory
$ tla register-archive -d tla@mercurial--convert
$ glog()
> {
> hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@"
> }
show graph log
$ glog -R tla-repo-hg
o 5 "move and rename a-link-2 file and src directory" files: c src/a-link src/a-link-2 src/b test/a-link test/b
|
o 4 "file to link and link to file test" files: src/a-link-2 src/b
|
o 3 "added second link and modify b" files: src/a-link-2 src/b
|
o 2 "added link to a and modify a" files: a src/a-link
|
o 1 "added a file, src and src/b (binary)" files: a src/b
|
o 0 "initial import" files:
$ hg up -q -R tla-repo-hg
$ hg -R tla-repo-hg manifest --debug
c4072c4b72e1cabace081888efa148ee80ca3cbb 644 a
0201ac32a3a8e86e303dff60366382a54b48a72e 644 c
c0067ba5ff0b7c9a3eb17270839d04614c435623 644 @ test/a-link
375f4263d86feacdea7e3c27100abd1560f2a973 644 @ test/b