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.
$ cat >> $HGRCPATH <<EOF
> [extensions]
> rebase=
> [phases]
> publish=False
> [merge]
> EOF
$ hg init repo
$ cd repo
$ echo a > a
$ echo b > b
$ hg commit -qAm ab
$ echo c >> a
$ echo c >> b
$ hg commit -qAm c
$ hg up -q ".^"
$ echo d >> a
$ echo d >> b
$ hg commit -qAm d
Testing on-failure=continue
$ echo on-failure=continue >> $HGRCPATH
$ hg rebase -s 1 -d 2 --tool false
rebasing 1:1f28a51c3c9b "c"
merging a
merging a failed!
merging b
merging b failed!
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg resolve --list
U a
U b
$ hg rebase --abort
rebase aborted
Testing on-failure=halt
$ echo on-failure=halt >> $HGRCPATH
$ hg rebase -s 1 -d 2 --tool false
rebasing 1:1f28a51c3c9b "c"
merging a
merging a failed!
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg resolve --list
U a
U b
$ hg rebase --abort
rebase aborted
Testing on-failure=prompt
$ cat <<EOS >> $HGRCPATH
> [merge]
> on-failure=prompt
> [ui]
> interactive=1
> EOS
$ cat <<EOS | hg rebase -s 1 -d 2 --tool false
> y
> n
> EOS
rebasing 1:1f28a51c3c9b "c"
merging a
merging a failed!
continue merge operation (yn)? y
merging b
merging b failed!
continue merge operation (yn)? n
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg resolve --list
U a
U b
$ hg rebase --abort
rebase aborted
Check that successful tool with failed post-check halts the merge
$ cat <<EOS >> $HGRCPATH
> [merge-tools]
> true.check=changed
> EOS
$ cat <<EOS | hg rebase -s 1 -d 2 --tool true
> y
> n
> n
> EOS
rebasing 1:1f28a51c3c9b "c"
merging a
output file a appears unchanged
was merge successful (yn)? y
merging b
output file b appears unchanged
was merge successful (yn)? n
merging b failed!
continue merge operation (yn)? n
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg resolve --list
R a
U b
$ hg rebase --abort
rebase aborted
Check that conflicts with conflict check also halts the merge
$ cat <<EOS >> $HGRCPATH
> [merge-tools]
> true.check=conflicts
> true.premerge=keep
> [merge]
> on-failure=halt
> EOS
$ hg rebase -s 1 -d 2 --tool true
rebasing 1:1f28a51c3c9b "c"
merging a
merging a failed!
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg resolve --list
U a
U b
$ hg rebase --abort
rebase aborted
Check that always-prompt also can halt the merge
$ cat <<EOS | hg rebase -s 1 -d 2 --tool true --config merge-tools.true.check=prompt
> y
> n
> EOS
rebasing 1:1f28a51c3c9b "c"
merging a
was merge of 'a' successful (yn)? y
merging b
was merge of 'b' successful (yn)? n
merging b failed!
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
$ hg resolve --list
R a
U b
$ hg rebase --abort
rebase aborted
Check that successful tool otherwise allows the merge to continue
$ hg rebase -s 1 -d 2 --tool echo --keep --config merge-tools.echo.premerge=keep
rebasing 1:1f28a51c3c9b "c"
merging a
$TESTTMP/repo/a *a~base* *a~other* (glob)
merging b
$TESTTMP/repo/b *b~base* *b~other* (glob)
Check that unshelve isn't broken by halting the merge
$ cat <<EOS >> $HGRCPATH
> [extensions]
> shelve =
> [merge-tools]
> false.check=conflicts
> false.premerge=false
> EOS
$ echo foo > shelve_file1
$ echo foo > shelve_file2
$ hg ci -qAm foo
$ echo bar >> shelve_file1
$ echo bar >> shelve_file2
$ hg shelve --list
$ hg shelve
shelved as default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo baz >> shelve_file1
$ echo baz >> shelve_file2
$ hg ci -m baz
$ hg unshelve --tool false --config merge-tools.false.premerge=keep
unshelving change 'default'
rebasing shelved changes
merging shelve_file1
merging shelve_file1 failed!
unresolved conflicts (see 'hg resolve', then 'hg unshelve --continue')
[240]
$ hg status --config commands.status.verbose=True
M shelve_file1
M shelve_file2
? shelve_file1.orig
# The repository is in an unfinished *unshelve* state.
# Unresolved merge conflicts:
#
# shelve_file1
# shelve_file2
#
# To mark files as resolved: hg resolve --mark FILE
# To continue: hg unshelve --continue
# To abort: hg unshelve --abort
$ hg resolve --tool false --all --re-merge
merging shelve_file1
merging shelve_file1 failed!
merge halted after failed merge (see hg resolve)
[240]
$ hg shelve --list
default (*s ago) * changes to: foo (glob)
$ hg unshelve --abort
unshelve of 'default' aborted