From: Marius Storm-Olsen <mstormo@gmail.com>
Date: Fri, 28 Jul 2017 15:26:48 GMT
Subject: Re: requesting permission to use some Git for Windows code
Message-ID: <d8fc1fdb-f326-d71d-f496-8293ed14bf68@gmail.com>
In-Reply-To: <CA+sFfMcAtStAfoc6Zaq7zW3cmYLu1QMX9_mmrRWe=M_GJYDeyw@mail.gmail.com>

Ditto, on any of my portions, if any left :)

-- 
.marius

On 7/28/2017 00:31, Brandon Casey wrote:
> Hi Philippe,
>
> Please feel free to use my portions of the mentioned works under the GPLv3.
>
> -Brandon
>
> On Tue, Jul 25, 2017 at 6:53 AM, Johannes Schindelin
> <Johannes.Schindelin@gmx.de> wrote:
>> Hi Philippe,
>>
>> I am not quite certain whether I have replied to this earlier or not.
>> Under the assumption that I did not, I'll send this mail; Cc:ed to the
>> mailing lists as discussed privately.
>>
>> On Fri, 23 Jun 2017, Philippe Joyez wrote:
>>
>>> This message is to request the permission to use code chunks from Git
>>> for Windows in GNU TeXmacs <http://texmacs.org/>, to which I contribute.
>>> The main developer of TeXmacs is Joris van der Hoeven (in cc).
>>>
>>> Context:
>>>
>>> Just like Git, TeXmacs originated on *nix platforms and was subsequently
>>> ported to windows using MinGW. Naturally, some issues we have in that
>>> port are the very same Git for Windows has faced.
>>>
>>> One specific problem you have solved and that TeXmacs still hasn't, is
>>> dealing with unicode filenames. By taking relevant pieces of code in Git
>>> for windows, I could easily come up with a patch that enables TeXmacs to
>>> handle unicode filenames in windows.
>>>
>>> Now, the problem is that Git code is GPL V2, while TeXmacs is GPL V3:
>>> Incorporating my patch in TeXmacs' trunk would be a violation of GPL
>>> V2... /unless/ we are granted the permission to do so by the authors of
>>> the code. This is precisely the reason for this message.
>> It is great that you can make use of the code!
>>
>> As to the licensing problem, I agree it is a hassle. The biggest obstacle
>> is that you have to have the consent of all the authors.
>>
>> You hereby have mine.
>>
>>> The chunks of code we would like to reuse are from these Git for Windows
>>> files:
>>> git-compat-util.h
>> This file is quite large, maybe you can cut down on the authors to contact
>> by restricting the `git annotate`/`git log`/`git shortlog` calls to
>> specific parts, using the `-L <start-line-no>,<end-line-no>` option?
>>
>>> ctype.c
>> $ git shortlog -nse ctype.c
>>       5  Junio C Hamano <gitster@pobox.com>
>>       4  René Scharfe <l.s.r@web.de>
>>       2  Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>>       1  Ben Walton <bdwalton@gmail.com>
>>       1  Brandon Casey <drafnel@gmail.com>
>>       1  Gary V. Vaughan <git@mlists.thewrittenword.com>
>>       1  Linus Torvalds <torvalds@linux-foundation.org>
>>       1  Namhyung Kim <namhyung@gmail.com>
>>
>> I *think* Ben Walton's change (189c860c9ec (kwset: use unsigned char to
>> store values with high-bit set, 2015-03-02)) is not copyright-able, as it
>> only changes the type from signed to unsigned. But I am not a lawyer ;-)
>>
>> Likewise, Namhyung Kim's change (1a191a22959 (ctype.c only wants
>> git-compat-util.h, 2012-02-10)) only changes which header is included.
>> That seems to be a too-obvious/too-trivial change to me.
>>
>> Also, it looks as if removing a comma as was done in 4b05548fc05 (enums:
>> omit trailing comma for portability, 2010-05-14) by Gary V. Vaughan would
>> not merit any copyright.
>>
>> If in doubt, you could simply take the version of ctype.c with those
>> changes reverted as basis of your work.
>>
>> You still have to get the consent of Junio, René, Duy, Brandon and Linus
>> to relicense the file's contents.
>>
>>> compat ¬
>>>     mingw.c
>> I count 35 authors other than myself for that file... Maybe you can narrow
>> down what you need?
>>
>>>     mingw.h
>> Still 29 authors other than me...
>>
>>>     win32.h
>> This is more manageable, as it only saw three authors. But then, you could
>> simply reimplement the functionality, it's just two functions, and I do
>> not think that get_file_attr() is implemented in the best way: we have a
>> function called err_win_to_posix() in compat/mingw.c which is much more
>> complete.
>>
>> Having said that, err_win_to_posix() is still not implemented in the best
>> way. The best way is to abuse Windows' own (undocumented) _doserrmap()
>> function along with the information in the header files winerror.h and
>> errno.h to generate the mapping. Those two files, as per mingw-w64's
>> headers, have the very nice preamble:
>>
>>          /**
>>           * This file has no copyright assigned and is placed in the Public Domain.
>>           * This file is part of the mingw-w64 runtime package.
>>           * No warranty is given; refer to the file DISCLAIMER.PD within this
>>           * package.
>>           */
>>
>> Therefore, the result has no copyright assigned and is placed in the
>> Public Domain and we can do the very same, too.
>>
>> As I wanted to have a Windows error -> errno mapping that I could
>> relicense as I see fit, anyway, I took this as an excellent opportunity to
>> generate exactly that.
>>
>> Please find the header attached. Here is how I generated that header file:
>>
>> -- snip --
>> cat >/tmp/generrmap.c <<EOF &&
>> #include <windows.h>
>> #include <stdio.h>
>>
>> static void map_code(unsigned long code, const char *id);
>>
>> int _main(int argc, char **argv)
>> {
>>          printf("/* This file has no copyright assigned and is placed in the "
>>                  "Public Domain. */\\n"
>>                  "\\n"
>>                  "#ifndef WINERR2ERRNO_H\\n"
>>                  "#define WINERR2ERRNO_H\\n"
>>                  "\\n"
>>                  "static int winerror2errno(long code)\\n"
>>                  "{\\n");
>> $(sed -n 's/^#define \([^ ]*\) __MSABI_LONG([1-9].*/\tmap_code(\1, "\1");/p' \
>>          </mingw64/x86_64-w64-mingw32/include/winerror.h)
>>          printf("\\tdefault: errno = EINVAL;\\n"
>>                  "\\t}\\n"
>>                  "\\n"
>>                  "\\treturn -1; /* Typical return value when errno was set */\\n"
>>                  "}\\n"
>>                  "\\n"
>>                  "#endif /* WINERR2ERRNO_H */\\n");
>>          fflush(stdout);
>>          return 0;
>> }
>>
>> /* Undocumented function in the MSVCRT */
>> extern void _dosmaperr(unsigned long code);
>>
>> static const char *errno2constant(int err, const char *id)
>> {
>>          switch (err) {
>> $(sed -n 's/^#define \([^ ]*\) \([0-9]*\)$/\tcase \2: return "\1";/p' \
>>          </mingw64/x86_64-w64-mingw32/include/errno.h)
>>          default:
>>                  fprintf(stderr, "Unhandled err: %d (for %s)\\n", err, id);
>>                  exit(1);
>>          }
>> }
>>
>> static void map_code(unsigned long code, const char *id)
>> {
>>          errno = 0;
>>          _dosmaperr(code);
>>          if (!errno) {
>>                  fprintf(stderr, "Unhandled id: '%s' (%ld)\\n", id, code);
>>                  exit(1);
>>          }
>>          if (errno != EINVAL)
>>                  printf("\\tcase %s: errno = %s;\\n",
>>                          id, errno2constant(errno, id));
>> }
>> EOF
>> gcc -g -nostdlib -o /tmp/generrmap.exe /tmp/generrmap.c -lmsvcr120 &&
>> /tmp/generrmap
>> -- snap --
>>
>>>     win32 ¬
>>>          dirent.c
>>>          dirent.h
>> I encourage you to have a look whether you really need that full-fledged
>> functionality.
>>
>> For vaguely related work, I recently reimplemented this differently, for
>> use in BusyBox-w32, where we really only need to have the file names. The
>> implementation is a lot cleaner, and I am happy to relicense this to
>> whatever license you see fit (even BSD):
>>
>>          https://github.com/git-for-windows/busybox-w32/commit/b76eee3aca
>>
>>>          lazyload.h
>> This one was authored by me, and I am happy to relicense it to GPLv3. Or
>> whatever license, really.
>>
>> Ciao,
>> Johannes