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
$ mkdir d1 d1/d11 d2
$ echo d1/a > d1/a
$ echo d1/ba > d1/ba
$ echo d1/a1 > d1/d11/a1
$ echo d1/b > d1/b
$ echo d2/b > d2/b
$ hg add d1/a d1/b d1/ba d1/d11/a1 d2/b
$ hg commit -m "intial"
Test single file
# One recorded copy, one copy to record after commit
$ hg cp d1/b d1/c
$ cp d1/b d1/d
$ hg add d1/d
$ hg ci -m 'copy d1/b to d1/c and d1/d'
$ hg st -C --change .
A d1/c
d1/b
A d1/d
# Errors out without --after for now
$ hg cp --at-rev . d1/b d1/d
abort: --at-rev requires --after
[10]
# Errors out with non-existent source
$ hg cp -A --at-rev . d1/non-existent d1/d
d1/non-existent: no such file in rev 55d1fd85ef0a
abort: no files to copy
[10]
# Errors out with non-existent destination
$ hg cp -A --at-rev . d1/b d1/non-existent
abort: d1/non-existent: copy destination does not exist in 8a9d70fa20c9
[10]
# Successful invocation
$ hg cp -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/8a9d70fa20c9-973ae357-copy.hg
# New copy is recorded, and previously recorded copy is also still there
$ hg st -C --change .
A d1/c
d1/b
A d1/d
d1/b
# Should get helpful message if we try to copy or rename after commit
$ hg cp --forget --at-rev . d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/3f7c325d3f9e-46f377bb-uncopy.hg
$ hg cp d1/b d1/d
d1/d: not overwriting - file already committed
('hg copy --at-rev .' to record the copy in the parent of the working copy)
[1]
$ hg mv d1/b d1/d
d1/d: not overwriting - file already committed
('hg rename --at-rev .' to record the rename in the parent of the working copy)
[1]
Test moved file (not copied) using 'hg cp' command
$ hg co 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ mv d1/b d1/d
$ hg rm -A d1/b
$ hg add d1/d
$ hg ci -m 'move d1/b to d1/d'
created new head
$ hg cp -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/519850c3ea27-153c8fbb-copy.hg
$ hg st -C --change .
A d1/d
d1/b
R d1/b
Test moved file (not copied) using 'hg mv' command
$ hg co 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mv d1/b d1/d
$ hg rm -A d1/b
$ hg add d1/d
$ hg ci -m 'move d1/b to d1/d'
created new head
$ hg mv -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/519850c3ea27-153c8fbb-copy.hg
$ hg st -C --change .
A d1/d
d1/b
R d1/b
Test moved file (not copied) for which source still exists
$ hg co 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cp d1/b d1/d
$ hg add d1/d
$ hg ci -m 'copy d1/b to d1/d'
created new head
$ hg mv -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/c8d0f6bcf7ca-1c9bb53e-copy.hg
$ hg st -C --change .
A d1/d
d1/b
Test using directory as destination
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cp -R d1 d3
$ hg add d3
adding d3/a
adding d3/b
adding d3/ba
adding d3/d11/a1
$ hg ci -m 'copy d1/ to d3/'
created new head
$ hg cp -A --at-rev . d1 d3
abort: d3: --at-rev does not support a directory as destination
[10]