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.
=========================================
Testing single head enforcement: Case A-4
=========================================
A repository is set to only accept a single head per name (typically named
branch). However, obsolete changesets can make this enforcement more
complicated, because they can be kept visible by other changeset on other
branch.
This case is part of a series of tests checking this behavior.
Category A: Involving obsolescence
TestCase 4: Partial rewrite of a branch to deinterleave it
.. old-state:
..
.. * 2 changesets on branch default
.. * 2 changesets on branch Z interleaved with the other one
..
.. new-state:
..
.. * 2 changesets on branch Z at the same location
.. * 1 changeset on default untouched (the lower one)
.. * 1 changeset on default moved on the other one
..
.. expected-result:
..
.. * only one head detected
..
.. graph-summary:
..
.. D ● (branch Z)
.. |
.. C ø⇠◔ C'
.. | |
.. B ● | (branch Z)
.. |/
.. A ●
.. |
.. ●
$ . $TESTDIR/testlib/push-checkheads-util.sh
$ cat >> $HGRCPATH << EOF
> [command-templates]
> log = "{node|short} [{branch}] ({phase}): {desc}\n"
> EOF
Test setup
----------
$ mkdir A4
$ cd A4
$ setuprepos single-head
creating basic server and client repo
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd client
$ hg branch Z
marked working directory as branch Z
(branches are permanent and global, did you want a bookmark?)
$ mkcommit B0
$ hg branch default --force
marked working directory as branch default
$ mkcommit C0
created new head
$ hg branch Z --force
marked working directory as branch Z
$ mkcommit D0
created new head
$ hg push --new-branch
pushing to $TESTTMP/A4/server
searching for changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 3 files
$ hg up 'desc("A0")'
0 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ mkcommit C1
created new head
$ hg debugobsolete `getid "desc(C0)"` `getid "desc(C1)"`
1 new obsolescence markers
obsoleted 1 changesets
1 new orphan changesets
$ hg heads
cfe9ed94fa4a [default] (draft): C1
78578c4306ce [Z] (draft): D0
$ hg log -G --hidden
@ cfe9ed94fa4a [default] (draft): C1
|
| * 78578c4306ce [Z] (draft): D0
| |
| x afc55ba2ce61 [default] (draft): C0
| |
| o 93e5c1321ece [Z] (draft): B0
|/
o 8aaa48160adc [default] (draft): A0
|
o 1e4be0697311 [default] (public): root
Actual testing
--------------
(force push to make sure we get the changeset on the remote)
$ hg push -r 'desc("C1")' --force
pushing to $TESTTMP/A4/server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
1 new obsolescence markers
obsoleted 1 changesets
1 new orphan changesets