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.
$ hg init
$ echo foo > foo
$ echo bar > bar
$ hg ci -qAm 'add foo bar'
$ echo foo2 >> foo
$ echo bleh > bar
$ hg ci -m 'change foo bar'
$ hg up -qC 0
$ hg mv foo foo1
$ echo foo1 > foo1
$ hg cat foo >> foo1
$ hg ci -m 'mv foo foo1'
created new head
$ hg merge
merging foo1 and foo to foo1
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg debugstate --no-dates
m 0 -2 unset bar
m 0 -2 unset foo1
copy: foo -> foo1
$ hg st -q
M bar
M foo1
Removing foo1 and bar:
$ cp foo1 F
$ cp bar B
$ hg rm -f foo1 bar
$ hg debugstate --no-dates
r 0 -1 set bar
r 0 -1 set foo1
copy: foo -> foo1
$ hg st -qC
R bar
R foo1
Re-adding foo1 and bar:
$ cp F foo1
$ cp B bar
$ hg add -v foo1 bar
adding bar
adding foo1
$ hg debugstate --no-dates
m 0 -2 unset bar
m 0 -2 unset foo1
copy: foo -> foo1
$ hg st -qC
M bar
M foo1
foo
Reverting foo1 and bar:
$ hg revert -vr . foo1 bar
saving current version of bar as bar.orig
saving current version of foo1 as foo1.orig
reverting bar
reverting foo1
$ hg debugstate --no-dates
m 0 -2 unset bar
m 0 -2 unset foo1
copy: foo -> foo1
$ hg st -qC
M bar
M foo1
foo
$ hg diff
Merge should not overwrite local file that is untracked after remove
$ rm *
$ hg up -qC
$ hg rm bar
$ hg ci -m 'remove bar'
$ echo 'memories of buried pirate treasure' > bar
$ hg merge
bar: untracked file differs
abort: untracked files in working directory differ from files in requested revision
[20]
$ cat bar
memories of buried pirate treasure
Those who use force will lose
$ hg merge -f
file 'bar' was deleted in local [working copy] but was modified in other [merge rev].
You can use (c)hanged version, leave (d)eleted, or leave (u)nresolved.
What do you want to do? u
merging foo1 and foo to foo1
0 files updated, 1 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ cat bar
bleh
$ hg st
M bar
M foo1