shared/calendarspec: fix printing of second ranges which start with 0

0..3 is not the same as 0..infinity, we need to check both ends of the range.
This logic was added in 3215e35c40, and back then
the field was called .value. .stop was added later and apparently wasn't taken
into account here.

src/shared/calendarspec.c

@@ -298,7 +298,7 @@ static void format_chain(FILE *f, int space, const CalendarComponent *c, bool us
                 return;
         }
 
-        if (usec && c->start == 0 && c->repeat == USEC_PER_SEC && !c->next) {
+        if (usec && c->start == 0 && c->stop < 0 && c->repeat == USEC_PER_SEC && !c->next) {
                 fputc('*', f);
                 return;
         }

src/test/test-calendarspec.c

@@ -162,6 +162,8 @@ TEST(calendar_spec_one) {
         test_one("00:00:1.0..3.8", "*-*-* 00:00:01..03");
         test_one("00:00:01..03", "*-*-* 00:00:01..03");
         test_one("00:00:01/2,02..03", "*-*-* 00:00:01/2,02..03");
+        test_one("*:4,30:0..3", "*-*-* *:04,30:00..03");
+        test_one("*:4,30:0/1", "*-*-* *:04,30:*");
         test_one("*-*~1 Utc", "*-*~01 00:00:00 UTC");
         test_one("*-*~05,3 ", "*-*~03,05 00:00:00");
         test_one("*-*~* 00:00:00", "*-*-* 00:00:00");
@@ -252,6 +254,9 @@ TEST(calendar_spec_from_string) {
         assert_se(calendar_spec_from_string("00:00:2300", &c) == -ERANGE);
         assert_se(calendar_spec_from_string("00:00:18446744073709551615", &c) == -ERANGE);
         assert_se(calendar_spec_from_string("@88588582097858858", &c) == -ERANGE);
+        assert_se(calendar_spec_from_string("*:4,30:*,5", &c) == -EINVAL);
+        assert_se(calendar_spec_from_string("*:4,30:5,*", &c) == -EINVAL);
+        assert_se(calendar_spec_from_string("*:4,30:*\n", &c) == -EINVAL);
 }
 
 DEFINE_TEST_MAIN(LOG_INFO);

test/fuzz/fuzz-calendarspec/cant-parse-printed

@@ -0,0 +1 @@
+*:4,30:0..5,0

test/fuzz/fuzz-calendarspec/print-loses-spec

@@ -0,0 +1 @@
+*:4,30:0..3