From 13755c09036aefe9209360bf0a94c3e2a83e12b8 Mon Sep 17 00:00:00 2001
From: lat9nq <22451773+lat9nq@users.noreply.github.com>
Date: Wed, 12 Jul 2023 02:34:02 -0400
Subject: time_zone: Account for leap years

Protects against invalid hour offsets during transitions to years
following leap years.
---
 src/common/time_zone.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/common/time_zone.cpp b/src/common/time_zone.cpp
index a25f8b040..1ee63bf80 100644
--- a/src/common/time_zone.cpp
+++ b/src/common/time_zone.cpp
@@ -35,11 +35,13 @@ std::string GetDefaultTimeZone() {
 
 // Results are not comparable to seconds since Epoch
 static std::time_t TmSpecToSeconds(const struct std::tm& spec) {
+    const int year = spec.tm_year - 1; // Years up to now
+    const int leap_years = year / 4 - year / 100;
     std::time_t cumulative = spec.tm_year;
-    cumulative = cumulative * 365 + spec.tm_yday; // Years to days
-    cumulative = cumulative * 24 + spec.tm_hour;  // Days to hours
-    cumulative = cumulative * 60 + spec.tm_min;   // Hours to minutes
-    cumulative = cumulative * 60 + spec.tm_sec;   // Minutes to seconds
+    cumulative = cumulative * 365 + leap_years + spec.tm_yday; // Years to days
+    cumulative = cumulative * 24 + spec.tm_hour;               // Days to hours
+    cumulative = cumulative * 60 + spec.tm_min;                // Hours to minutes
+    cumulative = cumulative * 60 + spec.tm_sec;                // Minutes to seconds
     return cumulative;
 }
 
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