>From 5b8a58981d5958dc882cab254bef7a3ecf8819a2 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sun, 19 Jul 2015 14:55:05 -0700 Subject: [PATCH] Two rules can't take effect at the same time * NEWS: Document this. * zic.8: Document simultaneity constraints. * zic.c (outzone): Check for two rules taking effect at the same time. --- NEWS | 4 ++++ zic.8 | 5 +++++ zic.c | 10 ++++++++++ 3 files changed, 19 insertions(+) diff --git a/NEWS b/NEWS index da98b19..b7593e7 100644 --- a/NEWS +++ b/NEWS @@ -21,6 +21,10 @@ Unreleased, experimental changes work in the default installation, they are not used in the data, and they are now considered obsolescent. + zic now checks that two rules don't take effect at the same time. + (Thanks to Jon Skeet and Arthur David Olson.) Constraints on + simultaneity are now documented. + Changes affecting installed data files Data entries have been simplified for Atlantic/Canary, Europe/Simferopol, diff --git a/zic.8 b/zic.8 index fecedf8..dfb01db 100644 --- a/zic.8 +++ b/zic.8 @@ -381,6 +381,11 @@ Continuation lines may contain information, just as zone lines do, indicating that the next line is a further continuation. .PP +If a zone changes at the same instant that a rule would otherwise take +effect in the earlier zone or continuation line, the rule is ignored. +In a single zone it is an error if two rules take effect at the same +instant, or if two zone changes take effect at the same instant. +.PP A link line has the form .sp .nf diff --git a/zic.c b/zic.c index bbcc4ef..96ab0e7 100644 --- a/zic.c +++ b/zic.c @@ -2375,6 +2375,16 @@ outzone(const struct zone * const zpfirst, const int zonecount) if (k < 0 || jtime < ktime) { k = j; ktime = jtime; + } else if (jtime == ktime) { + char const *dup_rules_msg = + _("two rules for same instant"); + eats(zp->z_filename, zp->z_linenum, + rp->r_filename, rp->r_linenum); + warning(dup_rules_msg); + rp = &zp->z_rules[k]; + eats(zp->z_filename, zp->z_linenum, + rp->r_filename, rp->r_linenum); + error(dup_rules_msg); } } if (k < 0) -- 2.1.4