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 no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ echo treemanifest >> .hg/requires
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
# uppercase directory name to test encoding
$ mkdir -p A/B
$ echo x > A/B/x
$ hg commit -qAm x
$ cd ..
# shallow clone from full
$ hgcloneshallow ssh://user@dummy/master shallow --noupdate
streaming all changes
4 files to transfer, 449 bytes of data
transferred 449 bytes in * seconds (*/sec) (glob)
searching for changes
no changes found
$ cd shallow
$ hg debugrequires
dotencode
dirstate-v2 (dirstate-v2 !)
exp-remotefilelog-repo-req-1
fncache
generaldelta
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
treemanifest
$ find .hg/store/meta | sort
.hg/store/meta
.hg/store/meta/_a
.hg/store/meta/_a/00manifest.i
.hg/store/meta/_a/_b
.hg/store/meta/_a/_b/00manifest.i
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cat A/B/x
x
$ ls .hg/store/data
$ echo foo > A/B/F
$ hg add A/B/F
$ hg ci -m 'local content'
$ ls .hg/store/data
ca31988f085bfb945cb8115b78fabdee40f741aa
$ cd ..
# shallow clone from shallow
$ hgcloneshallow ssh://user@dummy/shallow shallow2 --noupdate
streaming all changes
5 files to transfer, 1008 bytes of data
transferred 1008 bytes in * seconds (*/sec) (glob)
searching for changes
no changes found
$ cd shallow2
$ hg debugrequires
dotencode
dirstate-v2 (dirstate-v2 !)
exp-remotefilelog-repo-req-1
fncache
generaldelta
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
treemanifest
$ ls .hg/store/data
ca31988f085bfb945cb8115b78fabdee40f741aa
$ hg update
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat A/B/x
x
$ cd ..
# full clone from shallow
# - send stderr to /dev/null because the order of stdout/err causes
# flakiness here
$ hg clone --noupdate ssh://user@dummy/shallow full 2>/dev/null
streaming all changes
[100]
# getbundle full clone
$ printf '[server]\npreferuncompressed=False\n' >> master/.hg/hgrc
$ hgcloneshallow ssh://user@dummy/master shallow3
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets 18d955ee7ba0
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ ls shallow3/.hg/store/data
$ hg debugrequires -R shallow3/
dotencode
dirstate-v2 (dirstate-v2 !)
exp-remotefilelog-repo-req-1
fncache
generaldelta
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
treemanifest