On Fri, Jan 17, 2020 at 03:32:36PM +0100, SZEDER Gábor wrote: > On Mon, Jan 13, 2020 at 06:04:17PM +0100, SZEDER Gábor wrote: > > and 'GIT_TEST_ADD_I_USE_BUILTIN=1 ./t3701-add-interactive.sh -r 39,49' > > fails with: > > > > + test_must_fail force_color git add -p > > about to run diffFilter > > attempting to xwrite() 224 bytes to a fd with revents flags 0x4 > > test_must_fail: died by signal 13: force_color git add -p > > > > I don't understand why we get SIGPIPE right away instead of some error > > that we can act upon (ECONNRESET?). > > Doh', because it's a pipe, not a socket, that's why. pipe(7): > > "If all file descriptors referring to the read end of a pipe have > been closed, then a write(2) will cause a SIGPIPE signal to be > generated for the calling process." > > So ECONNRESET is definitely not the right error to set on POLLERR, > though I'm still not sure what the right one would be (perhaps > EPIPE?). Yes, if SIGPIPE is ignored, then that write() would produce EPIPE. So if you're trying to emulate it via POLLERR, that would be accurate. Of course it could fail for _other_ reasons, and I don't think we'd know what those are without actually calling write(). Practically speaking, though, if we know it's a pipe with a valid descriptor then any error is basically equivalent to EPIPE (we don't care how, but for whatever reason we couldn't write to the other end). -Peff
