view tests/bundles/rebase.sh @ 45095:8e04607023e5

procutil: ensure that procutil.std{out,err}.write() writes all bytes

Python 3 offers different kind of streams and it’s not guaranteed for all of
them that calling write() writes all bytes.

When Python is started in unbuffered mode, sys.std{out,err}.buffer are
instances of io.FileIO, whose write() can write less bytes for
platform-specific reasons (e.g. Linux has a 0x7ffff000 bytes maximum and could
write less if interrupted by a signal; when writing to Windows consoles, it’s
limited to 32767 bytes to avoid the "not enough space" error). This can lead to
silent loss of data, both when using sys.std{out,err}.buffer (which may in fact
not be a buffered stream) and when using the text streams sys.std{out,err}
(I’ve created a CPython bug report for that:
https://bugs.python.org/issue41221).

Python may fix the problem at some point. For now, we implement our own wrapper
for procutil.std{out,err} that calls the raw stream’s write() method until all
bytes have been written. We don’t use sys.std{out,err} for larger writes, so I
think it’s not worth the effort to patch them.

#!/usr/bin/env bash
hg init rebase
cd rebase

#  @  7: 'H'
#  |
#  | o  6: 'G'
#  |/|
#  o |  5: 'F'
#  | |
#  | o  4: 'E'
#  |/
#  | o  3: 'D'
#  | |
#  | o  2: 'C'
#  | |
#  | o  1: 'B'
#  |/
#  o  0: 'A'

echo A > A
hg ci -Am A
echo B > B
hg ci -Am B
echo C > C
hg ci -Am C
echo D > D
hg ci -Am D
hg up -q -C 0
echo E > E
hg ci -Am E
hg up -q -C 0
echo F > F
hg ci -Am F
hg merge -r 4
hg ci -m G
hg up -q -C 5
echo H > H
hg ci -Am H

hg bundle -a ../rebase.hg

cd ..
rm -Rf rebase