view mercurial/templates/map-cmdline.bisect @ 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.

%include map-cmdline.default

[templates]
changeset = '{cset}{lbisect}{branches}{bookmarks}{tags}{parents}{luser}{ldate}{summary}\n'
changeset_quiet = '{lshortbisect} {rev}:{node|short}\n'
changeset_verbose = '{cset}{lbisect}{branches}{bookmarks}{tags}{parents}{luser}{ldate}{lfiles}{lfile_copies_switch}{description}\n'
changeset_debug = '{fullcset}{lbisect}{branches}{bookmarks}{tags}{lphase}{parents}{manifest}{luser}{ldate}{lfile_mods}{lfile_adds}{lfile_dels}{lfile_copies_switch}{extras}{description}\n'

# We take the zeroth word in order to omit "(implicit)" in the label
bisectlabel = ' bisect.{word('0', bisect)}'

lbisect ='{label("log.bisect{if(bisect, bisectlabel)}",
                                "bisect:      {bisect}\n")}'
lshortbisect ='{label("log.bisect{if(bisect, bisectlabel)}",
                                    "{bisect|shortbisect}")}'