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.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ tipparents() {
> hg parents --template "{rev}:{node|short} {desc|firstline}\n" -r tip
> }
Test import and merge diffs
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda
adding a
$ echo a >> a
$ hg ci -m changea
$ echo c > c
$ hg ci -Am addc
adding c
$ hg up 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo b > b
$ hg ci -Am addb
adding b
created new head
$ hg up 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg merge 3
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m merge
$ hg export . > ../merge.diff
$ grep -v '^merge$' ../merge.diff > ../merge.nomsg.diff
$ cd ..
$ hg clone -r2 repo repo2
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 2 files
new changesets 07f494440405:890ecaa90481
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd repo2
$ hg pull -r3 ../repo
pulling from ../repo
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 102a90ea7b4a
(run 'hg heads' to see heads, 'hg merge' to merge)
Test without --exact and diff.p1 == workingdir.p1
$ hg up 1
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cat > $TESTTMP/editor.sh <<EOF
> env | grep HGEDITFORM
> echo merge > \$1
> EOF
$ HGEDITOR="sh $TESTTMP/editor.sh" hg import --edit ../merge.nomsg.diff
applying ../merge.nomsg.diff
HGEDITFORM=import.normal.merge
$ tipparents
1:540395c44225 changea
3:102a90ea7b4a addb
$ hg strip --no-backup tip
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Test without --exact and diff.p1 != workingdir.p1
$ hg up 2
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import ../merge.diff
applying ../merge.diff
warning: import the patch as a normal revision
(use --exact to import the patch as a merge)
$ tipparents
2:890ecaa90481 addc
$ hg strip --no-backup tip
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Test with --exact
$ hg import --exact ../merge.diff
applying ../merge.diff
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ tipparents
1:540395c44225 changea
3:102a90ea7b4a addb
$ hg strip --no-backup tip
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Test with --bypass and diff.p1 == workingdir.p1
$ hg up 1
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --bypass ../merge.diff
applying ../merge.diff
$ tipparents
1:540395c44225 changea
3:102a90ea7b4a addb
$ hg strip --no-backup tip
Test with --bypass and diff.p1 != workingdir.p1
$ hg up 2
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --bypass ../merge.diff
applying ../merge.diff
warning: import the patch as a normal revision
(use --exact to import the patch as a merge)
$ tipparents
2:890ecaa90481 addc
$ hg strip --no-backup tip
Test with --bypass and --exact
$ hg import --bypass --exact ../merge.diff
applying ../merge.diff
$ tipparents
1:540395c44225 changea
3:102a90ea7b4a addb
$ hg strip --no-backup tip
$ cd ..
Test that --exact on a bad header doesn't corrupt the repo (issue3616)
$ hg init repo3
$ cd repo3
$ echo a>a
$ hg ci -Aqm0
$ echo a>>a
$ hg ci -m1
$ echo a>>a
$ hg ci -m2
$ echo a>a
$ echo b>>a
$ echo a>>a
$ hg ci -m3
$ hg export 2 | head -7 > ../a.patch
$ hg export tip > out
>>> apatch = open("../a.patch", "ab")
>>> apatch.write(b"".join(open("out", 'rb').readlines()[7:])) and None
$ cd ..
$ hg clone -qr0 repo3 repo3-clone
$ cd repo3-clone
$ hg pull -qr1 ../repo3
$ hg import --exact ../a.patch
applying ../a.patch
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
patching file a
Hunk #1 succeeded at 1 with fuzz 1 (offset -1 lines).
transaction abort!
rollback completed
abort: patch is damaged or loses information
[255]
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 2 changesets with 2 changes to 1 files