Merge branch 'jk/no-sigpipe-during-network-transport'

On platforms where "git fetch" is killed with SIGPIPE (e.g. OSX),
the upload-pack that runs on the other end that hangs up after
detecting an error could cause "git fetch" to die with a signal,
which led to a flakey test.  "git fetch" now ignores SIGPIPE during
the network portion of its operation (this is not a problem as we
check the return status from our write(2)s).

* jk/no-sigpipe-during-network-transport:
  fetch: ignore SIGPIPE during network operation
  fetch: avoid calling write_or_die()

builtin/fetch.c

@@ -1556,7 +1556,9 @@ static int fetch_one(struct remote *remote, int argc, const char **argv, int pru
 
 	sigchain_push_common(unlock_pack_on_signal);
 	atexit(unlock_pack);
+	sigchain_push(SIGPIPE, SIG_IGN);
 	exit_code = do_fetch(gtransport, &rs);
+	sigchain_pop(SIGPIPE);
 	refspec_clear(&rs);
 	transport_disconnect(gtransport);
 	gtransport = NULL;

fetch-pack.c

@@ -191,8 +191,10 @@ static void send_request(struct fetch_pack_args *args,
 	if (args->stateless_rpc) {
 		send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 		packet_flush(fd);
-	} else
-		write_or_die(fd, buf->buf, buf->len);
+	} else {
+		if (write_in_full(fd, buf->buf, buf->len) < 0)
+			die_errno(_("unable to write to remote"));
+	}
 }
 
 static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
@@ -1163,7 +1165,8 @@ static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
 
 	/* Send request */
 	packet_buf_flush(&req_buf);
-	write_or_die(fd_out, req_buf.buf, req_buf.len);
+	if (write_in_full(fd_out, req_buf.buf, req_buf.len) < 0)
+		die_errno(_("unable to write request to remote"));
 
 	strbuf_release(&req_buf);
 	return ret;

pkt-line.c

@@ -88,13 +88,15 @@ static void packet_trace(const char *buf, unsigned int len, int write)
 void packet_flush(int fd)
 {
 	packet_trace("0000", 4, 1);
-	write_or_die(fd, "0000", 4);
+	if (write_in_full(fd, "0000", 4) < 0)
+		die_errno(_("unable to write flush packet"));
 }
 
 void packet_delim(int fd)
 {
 	packet_trace("0001", 4, 1);
-	write_or_die(fd, "0001", 4);
+	if (write_in_full(fd, "0001", 4) < 0)
+		die_errno(_("unable to write delim packet"));
 }
 
 int packet_flush_gently(int fd)