branch: elpa/datetime
commit ecc98a0b2d9b465c30f8417f2f532cc22881064b
Author: Paul Pogonyshev <pogonys...@gmail.com>
Commit: Paul Pogonyshev <pogonys...@gmail.com>
Fix several issues that would sometimes cause the library to pick wrong
timezone name variant (DST vs. normal).
---
datetime.el | 6 +++-
dev/HarvestData.java | 87 ++++++++++++++++++++++++++++++++++++++++++---------
test/format.el | 30 +++++++++++++++---
timezone-data.extmap | Bin 889713 -> 900579 bytes
4 files changed, 104 insertions(+), 19 deletions(-)
diff --git a/datetime.el b/datetime.el
index 7a6308347f..6596a4d6e1 100644
--- a/datetime.el
+++ b/datetime.el
@@ -798,7 +798,11 @@ to this function.
day-of-month -1))
(offset-before (plist-get rule :before)))
(unless transitions
- (push offset-before transitions))
+ ;; Preserve our DST "flag" across year boundary.
+ (push (if (floatp (car (last (aref all-year-transitions (1-
year-offset)))))
+ (float offset-before)
+ offset-before)
+ transitions))
(when day-of-week
(let ((current-weekday (% (+ year-day (aref
datetime--gregorian-first-day-of-year (mod year 400))) 7)))
(setq year-day (if (< day-of-month 0) (- year-day (mod (-
day-of-week current-weekday) 7)) (+ year-day (mod (- day-of-week
current-weekday) 7))))))
diff --git a/dev/HarvestData.java b/dev/HarvestData.java
index 7eb866dc55..8735a5d523 100644
--- a/dev/HarvestData.java
+++ b/dev/HarvestData.java
@@ -298,26 +298,52 @@ public class HarvestData
LocalDateTime first =
LocalDateTime.ofInstant (transitions.get (0).getInstant (), ZoneOffset.UTC);
int base_year = Year.of (first.get
(ChronoField.YEAR)).getValue ();
long base = Year.of (first.get
(ChronoField.YEAR)).atDay (1).atStartOfDay ().toInstant
(ZoneOffset.UTC).getEpochSecond ();
- int last_offset = transitions.get
(0).getOffsetBefore ().getTotalSeconds ();
+ Offset last_offset = new Offset
(transitions.get (0).getOffsetBefore ().getTotalSeconds (), false);
List <Object> zone_data = new ArrayList <> ();
List <List <Object>> transition_data = new ArrayList <> ();
- for (ZoneOffsetTransition transition : transitions) {
- int year_offset = (int) ((transition.getInstant
().getEpochSecond () - base) / AVERAGE_SECONDS_IN_YEAR);
- if ((transition.getInstant ().getEpochSecond () + 1 -
base) % AVERAGE_SECONDS_IN_YEAR < 1)
- System.err.printf ("*Warning*: timezone '%s', offset
transition at %s would be a potential rounding error\n", timezone.getId (),
transition.getInstant ());
+ for (int k = 0; k < transitions.size (); k++) {
+ var transition = transitions.get (k);
+ var instant = transition.getInstant ();
+ last_offset = addTransition (timezone, transition_data,
instant, base, last_offset, transition.getOffsetAfter ());
+
+ // Quite a few timezones have DST changes not covered by
the exposed transitions (see
+ // 'standardTransitions' in 'ZoneRules.java', no way to
extract those without hacks).
+ // Because of that, we'd sometimes use invalid DST/non-DST
timezone name variant. As a
+ // workaround, we scan instants between subsequent
"official" transitions with a day step
+ // (should be more than enough) and check if DST changes.
If yes, we use binary search to
+ // finally pinpoint the exact instant of the change.
+ Instant limit;
+ if (k + 1 < transitions.size ())
+ limit = transitions.get (k + 1).getInstant ();
+ else if (rules.getTransitionRules ().isEmpty ())
+ limit = instant.plusSeconds (86400 * 365 * 25);
+ else
+ continue;
+
+ while (true) {
+ var next = instant.plusSeconds (86400);
+ if (!next.isBefore (limit))
+ break;
+
+ if (!Objects.equals (Offset.at (rules, next),
last_offset)) {
+ var before = instant;
+ var after = next;
- while (year_offset >= transition_data.size ())
- transition_data.add (new ArrayList <> (Arrays.asList
(last_offset)));
+ while (after.getEpochSecond () -
before.getEpochSecond () > 1) {
+ var middle = Instant.ofEpochSecond
((after.getEpochSecond () + before.getEpochSecond ()) / 2);
+ if (Objects.equals (Offset.at (rules, middle),
last_offset))
+ before = middle;
+ else
+ after = middle;
+ }
- transition_data.get (year_offset).add
(transition.getInstant ().getEpochSecond () - (base + year_offset *
AVERAGE_SECONDS_IN_YEAR));
- last_offset = transition.getOffsetAfter ().getTotalSeconds
();
+ last_offset = addTransition (timezone,
transition_data, after, base, last_offset, rules.getOffset (next));
+ next = after;
+ }
- // Floating-point offset is our internal mark of a
transition to DST.
- // Java is over-eager to convert ints to float for us, so
we format
- // them as strings manually now and add '.0' if
appropriate.
- boolean to_dst = !Objects.equals
(transition.getOffsetAfter (), rules.getStandardOffset (transition.getInstant
()));
- transition_data.get (year_offset).add (String.format
(to_dst ? "%d.0" : "%d", last_offset));
+ instant = next;
+ }
}
List <Object> transition_rule_data = new ArrayList <> ();
@@ -374,6 +400,22 @@ public class HarvestData
System.out.println (")");
}
+ protected static Offset addTransition (ZoneId timezone, List <List
<Object>> transition_data, Instant instant, long base, Offset last_offset,
ZoneOffset new_offset)
+ {
+ int year_offset = (int) ((instant.getEpochSecond () - base) /
AVERAGE_SECONDS_IN_YEAR);
+ if ((instant.getEpochSecond () + 1 - base) % AVERAGE_SECONDS_IN_YEAR <
1)
+ System.err.printf ("*Warning*: timezone '%s', offset transition at
%s would be a potential rounding error\n", timezone.getId (), instant);
+
+ while (year_offset >= transition_data.size ())
+ transition_data.add (new ArrayList <> (List.of (last_offset.toLisp
())));
+
+ transition_data.get (year_offset).add (instant.getEpochSecond () -
(base + year_offset * AVERAGE_SECONDS_IN_YEAR));
+
+ last_offset = new Offset (new_offset.getTotalSeconds (),
timezone.getRules ().isDaylightSavings (instant));
+ transition_data.get (year_offset).add (last_offset.toLisp ());
+ return last_offset;
+ }
+
protected static void printTimezoneNameData () throws Exception
{
@@ -574,4 +616,21 @@ public class HarvestData
{
return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
}
+
+
+ protected static record Offset (int seconds, boolean dst)
+ {
+ public static Offset at (ZoneRules rules, Instant instant)
+ {
+ return new Offset (rules.getOffset (instant).getTotalSeconds (),
rules.isDaylightSavings (instant));
+ }
+
+ // Floating-point offset is our internal Lisp-level mark of a
transition to DST.
+ // Java is over-eager to convert ints to float for us, so we format
them as
+ // strings manually now and add '.0' if appropriate.
+ public Object toLisp ()
+ {
+ return String.format (dst ? "%d.0" : "%d", seconds);
+ }
+ }
}
diff --git a/test/format.el b/test/format.el
index 40d79f8d9f..b8af6663d4 100644
--- a/test/format.el
+++ b/test/format.el
@@ -115,10 +115,32 @@
(datetime--test-formatter-around-transition 1412438400)))
(ert-deftest datetime-formatting-with-timezone-name-1 ()
- (datetime--test-set-up-formatter 'Europe/Berlin 'en "yyyy-MM-dd HH:mm:ss z"
- ;; Rule-based transition on 2014-10-26. Should also result in
- ;; timezone name changing between CEST and CET.
- (datetime--test-formatter-around-transition 1414285200)))
+ (dolist (timezone (datetime-list-timezones))
+ (datetime--test-set-up-formatter timezone 'en "yyyy-MM-dd HH:mm:ss z"
+ ;; Rule-based transition on 2014-10-26. In some timezones should also
result in name
+ ;; changing, e.g. between CEST and CET.
+ (datetime--test-formatter-around-transition 1414285200))))
+
+(ert-deftest datetime-formatting-with-timezone-name-2 ()
+ ;; Many timezones had special relations with DST (see comments in
'HarvestData.java'), so
+ ;; resulting name varies a lot. Make sure we handle all that correctly.
Too much to test all
+ ;; timezones, only some selected.
+ (dolist (timezone '(Africa/Algiers Africa/Tripoli Africa/Windhoek
+ America/Anchorage America/Argentina/Buenos_Aires
America/Argentina/Ushuaia America/Chihuahua America/Dawson America/Indiana/Knox
America/Iqaluit America/Kentucky/Louisville America/Whitehorse
+ Antarctica/McMurdo Antarctica/Palmer
+ Asia/Almaty Asia/Ashkhabad Asia/Baku Asia/Bishkek
Asia/Damascus Asia/Istanbul Asia/Kamchatka Asia/Omsk Asia/Singapore
Asia/Tashkent Asia/Tbilisi Asia/Vladivostok Asia/Yerevan
+ Atlantic/Azores
+ Canada/Yukon
+ Chile/EasterIsland
+ Europe/Belfast Europe/Kaliningrad Europe/Lisbon
Europe/Minsk Europe/Moscow Europe/Simferopol Europe/Tallinn Europe/Warsaw
+ GB Libya NZ
+ Pacific/Auckland Pacific/Norfolk
+ Poland Portugal
+ US/Alaska US/Aleutian US/Pacific
+ W-SU))
+ (datetime--test-set-up-formatter timezone 'en "yyyy-MM-dd HH:mm:ss z"
+ ;; Exact numbers don't matter much, we just need to skip a few months
each time.
+ (datetime--test-formatter (mapcar (lambda (k) (* k 7000000))
(number-sequence -300 400))))))
(ert-deftest datetime-formatting-day-periods ()
(let (times)
diff --git a/timezone-data.extmap b/timezone-data.extmap
index bf074b459f..731fd92781 100644
Binary files a/timezone-data.extmap and b/timezone-data.extmap differ
