git p4 test: wait longer for p4d to start and test its pid

Running tests at high parallelism on a slow machine, 5 sec is
not enough to wait for p4d to start.  Change it to 5 minutes,
adding an environment variable P4D_START_PATIENCE to shrink
that if needed in automated test environments.

Also check if the pid of the p4d that we started is still
around.  If not, quit waiting for it immediately.

Remove all the confusing && chaining and simplify the code.

Thanks-to: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-git-p4.sh

@@ -33,17 +33,42 @@ pidfile="$TRASH_DIRECTORY/p4d.pid"
 
 start_p4d() {
 	mkdir -p "$db" "$cli" "$git" &&
+	rm -f "$pidfile" &&
 	(
 		p4d -q -r "$db" -p $P4DPORT &
 		echo $! >"$pidfile"
 	) &&
-	for i in 1 2 3 4 5 ; do
-		p4 info >/dev/null 2>&1 && break || true &&
-		echo waiting for p4d to start &&
+
+	# This gives p4d a long time to start up, as it can be
+	# quite slow depending on the machine.  Set this environment
+	# variable to something smaller to fail faster in, say,
+	# an automated test setup.  If the p4d process dies, that
+	# will be caught with the "kill -0" check below.
+	i=${P4D_START_PATIENCE:-300}
+	pid=$(cat "$pidfile")
+	ready=
+	while test $i -gt 0
+	do
+		# succeed when p4 client commands start to work
+		if p4 info >/dev/null 2>&1
+		then
+			ready=true
+			break
+		fi
+		# fail if p4d died
+		kill -0 $pid 2>/dev/null || break
+		echo waiting for p4d to start
 		sleep 1
-	done &&
-	# complain if it never started
-	p4 info >/dev/null &&
+		i=$(( $i - 1 ))
+	done
+
+	if test -z "$ready"
+	then
+		# p4d failed to start
+		return 1
+	fi
+
+	# build a client
 	(
 		cd "$cli" &&
 		p4 client -i <<-EOF
@@ -53,6 +78,7 @@ start_p4d() {
 		View: //depot/... //client/...
 		EOF
 	)
+	return 0
 }
 
 kill_p4d() {