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
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ echo z > z
$ hg commit -qAm x1
$ echo x2 > x
$ echo z2 > z
$ hg commit -qAm x2
$ hg bookmark foo
$ cd ..
# prefetch a revision w/ a sparse checkout
$ hgcloneshallow ssh://user@dummy/master shallow --noupdate
streaming all changes
2 files to transfer, 527 bytes of data (no-zstd !)
transferred 527 bytes in * seconds (* */sec) (glob) (no-zstd !)
2 files to transfer, 534 bytes of data (zstd !)
transferred 534 bytes in * seconds (* */sec) (glob) (zstd !)
searching for changes
no changes found
$ cd shallow
$ printf "[extensions]\nsparse=\n" >> .hg/hgrc
$ hg debugsparse -I x
$ hg prefetch -r 0
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ hg cat -r 0 x
x
$ hg debugsparse -I z
$ hg prefetch -r 0
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ hg cat -r 0 z
z
# prefetch sparse only on pull when configured
$ printf "[remotefilelog]\npullprefetch=bookmark()\n" >> .hg/hgrc
$ hg strip tip
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/876b1317060d-b2e91d8d-backup.hg (glob)
2 files fetched over 2 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ hg debugsparse --delete z
$ clearcache
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
updating bookmark foo
added 1 changesets with 0 changes to 0 files
new changesets 876b1317060d
(run 'hg update' to get a working copy)
prefetching file contents
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
# Dont consider filtered files when doing copy tracing
## Push an unrelated commit
$ cd ../
$ hgcloneshallow ssh://user@dummy/master shallow2
streaming all changes
2 files to transfer, 527 bytes of data (no-zstd !)
transferred 527 bytes in * seconds (*) (glob) (no-zstd !)
2 files to transfer, 534 bytes of data (zstd !)
transferred 534 bytes in * seconds (* */sec) (glob) (zstd !)
searching for changes
no changes found
updating to branch default
2 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)
$ cd shallow2
$ printf "[extensions]\nsparse=\n" >> .hg/hgrc
$ hg up -q 0
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ touch a
$ hg ci -Aqm a
$ hg push -q -f
## Pull the unrelated commit and rebase onto it - verify unrelated file was not
pulled
$ cd ../shallow
$ hg up -q 1
$ hg pull -q
$ hg debugsparse -I z
$ clearcache
$ hg prefetch -r '. + .^' -I x -I z
4 files fetched over 1 fetches - (4 misses, 0.00% hit ratio) over * (glob)
$ hg rebase -d 2 --keep
rebasing 1:876b1317060d foo "x2"