Fixed bug #81458: Regression: Incorrect difference after timezone change

NEWS

@@ -7,6 +7,10 @@ PHP                                                                        NEWS
   . Fixed bug #78647 (SEGFAULT in zend_do_perform_implementation_check).
     (Nikita)
 
+- Date:
+  . Fixed bug #81458 (Regression Incorrect difference after timezone change).
+    (Derick)
+
 - GD:
   . Fixed bug #71316 (libpng warning from imagecreatefromstring). (cmb)
 

ext/date/lib/interval.c

@@ -59,7 +59,7 @@ timelib_rel_time *timelib_diff(timelib_time *one, timelib_time *two)
 	rt->s = two->s - one->s;
 	rt->us = two->us - one->us;
 
-	rt->days = fabs(floor((one->sse - two->sse - (dst_h_corr * 3600) - (dst_m_corr * 60)) / 86400));
+	rt->days = timelib_diff_days(one, two);
 
 	/* Fall Back: Cater for transition period, where rt->invert is 0, but there are negative numbers */
 	if (one->dst == 1 && two->dst == 0) {
@@ -147,6 +147,37 @@ timelib_rel_time *timelib_diff(timelib_time *one, timelib_time *two)
 	return rt;
 }
 
+
+int timelib_diff_days(timelib_time *one, timelib_time *two)
+{
+	int days = 0;
+
+	if (timelib_same_timezone(one, two)) {
+		timelib_time *earliest, *latest;
+		double earliest_time, latest_time;
+
+		if (timelib_time_compare(one, two) < 0) {
+			earliest = one;
+			latest = two;
+		} else {
+			earliest = two;
+			latest = one;
+		}
+		timelib_hmsf_to_decimal_hour(earliest->h, earliest->i, earliest->s, earliest->us, &earliest_time);
+		timelib_hmsf_to_decimal_hour(latest->h, latest->i, latest->s, latest->us, &latest_time);
+
+		days = llabs(timelib_epoch_days_from_time(one) - timelib_epoch_days_from_time(two));
+		if (latest_time < earliest_time && days > 0) {
+			days--;
+		}
+	} else {
+		days = fabs(floor(one->sse - two->sse) / 86400);
+	}
+
+	return days;
+}
+
+
 timelib_time *timelib_add(timelib_time *old_time, timelib_rel_time *interval)
 {
 	int bias = 1;

ext/date/lib/parse_tz.c

@@ -930,3 +930,23 @@ timelib_sll timelib_get_current_offset(timelib_time *t)
 			return 0;
 	}
 }
+
+int timelib_same_timezone(timelib_time *one, timelib_time *two)
+{
+    if (one->zone_type != two->zone_type) {
+        return 0;
+    }
+
+    if (one->zone_type == TIMELIB_ZONETYPE_ABBR || one->zone_type == TIMELIB_ZONETYPE_OFFSET) {
+        if ((one->z + (one->dst * 3600)) == (two->z + (two->dst * 3600))) {
+            return 1;
+        }
+        return 0;
+    }
+
+    if (one->zone_type == TIMELIB_ZONETYPE_ID && strcmp(one->tz_info->name, two->tz_info->name) == 0) {
+        return 1;
+    }
+
+    return 0;
+}

ext/date/lib/timelib.c

@@ -207,6 +207,15 @@ void timelib_hms_to_decimal_hour(int hour, int min, int sec, double *h)
 	}
 }
 
+void timelib_hmsf_to_decimal_hour(int hour, int min, int sec, int us, double *h)
+{
+	if (hour > 0) {
+		*h = ((double)hour + (double)min / MINS_PER_HOUR + (double)sec / SECS_PER_HOUR) + (double)us / USECS_PER_HOUR;
+	} else {
+		*h = ((double)hour - (double)min / MINS_PER_HOUR - (double)sec / SECS_PER_HOUR) - (double)us / USECS_PER_HOUR;
+	}
+}
+
 timelib_sll timelib_hms_to_seconds(timelib_sll h, timelib_sll m, timelib_sll s)
 {
 	return (h * SECS_PER_HOUR) + (m * 60) + s;

ext/date/lib/timelib.h

@@ -30,9 +30,9 @@
 # include "timelib_config.h"
 #endif
 
-#define TIMELIB_VERSION 202108
-#define TIMELIB_EXTENDED_VERSION 20210801
-#define TIMELIB_ASCII_VERSION "2021.08"
+#define TIMELIB_VERSION 202110
+#define TIMELIB_EXTENDED_VERSION 20211001
+#define TIMELIB_ASCII_VERSION "2021.10"
 
 #include <stdlib.h>
 #include <stdbool.h>
@@ -799,6 +799,16 @@ timelib_time_offset *timelib_get_time_zone_info(timelib_sll ts, timelib_tzinfo *
  */
 timelib_sll timelib_get_current_offset(timelib_time *t);
 
+/**
+ * Returns whether the timezone information in *one and *two are the same
+ *
+ * A timezone is considered the same if:
+ * - the ->zone_type values are the same for *one and *two
+ * - for TYPE_ABBR and TYPE_OFFSET, ->z + (->dst * 3600), is the same
+ * - for TYPE_ID, the zone's names are the same
+ */
+int timelib_same_timezone(timelib_time *one, timelib_time *two);
+
 /**
  * Displays debugging information about the time zone information in 'tz'.
  */
@@ -961,6 +971,11 @@ void timelib_decimal_hour_to_hms(double h, int *hour, int *min, int *sec);
  */
 void timelib_hms_to_decimal_hour(int hour, int min, int sec, double *h);
 
+/**
+ * Converts hour/min/sec/micro sec values into a decimal hour
+ */
+void timelib_hmsf_to_decimal_hour(int hour, int min, int sec, int us, double *h);
+
 /**
  * Converts hour/min/sec values into seconds
  */
@@ -1027,6 +1042,15 @@ int timelib_astro_rise_set_altitude(timelib_time *time, double lon, double lat,
  */
 timelib_rel_time *timelib_diff(timelib_time *one, timelib_time *two);
 
+/**
+ * Calculates the difference in full days between two times
+ *
+ * The result is the number of full days between 'one' and 'two'. It does take
+ * into account 23 and 25 hour (and variants) days when the zone_type
+ * is TIMELIB_ZONETYPE_ID and have the same TZID for 'one' and 'two'.
+ */
+int timelib_diff_days(timelib_time *one, timelib_time *two);
+
 /**
  * Adds the relative time information 'interval' to the base time 't'.
  *

ext/date/lib/timelib_private.h

@@ -84,9 +84,12 @@
 #define TIMELIB_TIME_PART_DONT_KEEP               0x00
 #define TIMELIB_TIME_PART_KEEP                    0x01
 
+#define MINS_PER_HOUR     60
 #define SECS_PER_ERA   TIMELIB_LL_CONST(12622780800)
 #define SECS_PER_DAY   86400
 #define SECS_PER_HOUR   3600
+#define USECS_PER_HOUR TIMELIB_LL_CONST(3600000000)
+
 #define DAYS_PER_WEEK      7
 #define DAYS_PER_YEAR    365
 #define DAYS_PER_LYEAR   366

ext/date/tests/bug81458.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Test for bug #81458: Regression in PHP 8.1: Incorrect difference after timezone change
+--FILE--
+<?php
+$first = (new DateTime('2018-07-01 00:00:00.000000 America/Toronto'))->setTimezone(new DateTimeZone('UTC'));
+$second = new DateTime('2018-07-02 00:00:00.000000 America/Toronto');
+
+var_dump($first->diff($second)->days);
+var_dump($first->diff($second)->d);
+?>
+--EXPECT--
+int(1)
+int(1)