Hi brian, On Mon, 29 Apr 2019, brian m. carlson wrote:
> On Mon, Apr 29, 2019 at 03:04:36PM -0700, Thomas Braun via GitGitGadget wrote: > > From: Thomas Braun <thomas.br...@byte-physics.de> > > > > Since commit 0c499ea60f (send-pack: demultiplex a sideband stream with > > status data, 2010-02-05) the built-in send-pack uses the side-band-64k > > capability if advertised by the server. > > > > Unfortunately this breaks pushing over the dump git protocol if used > > over a network connection when using MinGW (but *not* when using > > mingw-w64). > > > > The detailed reasons for this, are courtesy of Jeff Preshing, quoted > > from https://groups.google.com/d/msg/msysgit/at8D7J-h7mw/eaLujILGUWoJ: > > > > MinGW wraps Windows sockets in CRT file descriptors in order to > > mimic the functionality of POSIX sockets. This causes msvcrt.dll > > to treat sockets as Installable File System (IFS) handles, > > calling ReadFile, WriteFile, DuplicateHandle and CloseHandle on > > them. This approach works well in simple cases on recent > > versions of Windows, but does not support all usage patterns. > > In particular, using this approach, any attempt to read & write > > concurrently on the same socket (from one or more processes) > > will deadlock in a scenario where the read waits for a response > > from the server which is only invoked after the write. This is > > what send_pack currently attempts to do in the use_sideband > > codepath. > > Since this is a platform-specific issue, can we address this using a > compile-time constant instead of a config option? It would be better to > do the right thing automatically in this case and not have to have > people set a config option. It will also allow us to not to have to > maintain a config option indefinitely if MinGW becomes more capable in > the future. I was really not sure at the time whether this would be fixed in MinGW at some stage, and with the switch to mingw-w64 (by moving from MSys to MSYS2 as of Git for Windows 2.x) we do not really have any concrete need for it anymore. I just thought that it might benefit somebody (it was my impression that Hannes Sixt still built his own copy with MSys/MinGW, and we do have a track record of maintaining certain things even for single users, see e.g. our insistence on creating the .git/branches/ directory upon `git init`). But if the consensus is that we do not need this at all anymore, I'll be just as happy to drop that patch. Ciao, Dscho
