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decode timestamp without timezone as local DateTime and decode timestamp with timezone respecting the timezone defined in the connection #342

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decode timestamp without timezone as local DateTime and decode timestamp with timezone respecting the timezone defined in the connection #342

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901c5c7
decode timestamp without timezone as local DateTime and decode timest…
Jul 19, 2024
485351f
add more flexibility on how timestamp and timestaptz types are decode…
Jul 22, 2024
0b1e037
add more flexibility on how timestamp and timestaptz types are decode…
Jul 22, 2024
558f2ef
fix define location for TZDateTime.toLocal()
Jul 23, 2024
ab75ea7
fix decode timestamp without timezone as local DateTime, ignore past …
Jul 26, 2024
f239799
extract method to create a PostgreSQL Epoch Base DateTime using the c…
Aug 5, 2024
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20 changes: 18 additions & 2 deletions lib/src/types/binary_codec.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -796,7 +796,15 @@ class PostgresBinaryDecoder {
if (dinput.timeZone.forceDecodeDateAsUTC) {
return DateTime.utc(2000).add(Duration(days: value));
}
return DateTime(2000).add(Duration(days: value));
// https://github.com/dart-lang/sdk/issues/56312
// ignore past timestamp transitions and use only current timestamp in local datetime
final nowDt = DateTime.now();
var baseDt = DateTime(2000);
if (baseDt.timeZoneOffset != nowDt.timeZoneOffset) {
final difference = baseDt.timeZoneOffset - nowDt.timeZoneOffset;
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I'm wondering, without fully seeing the context, if this operation is always valid. E.g. can this be close to or larger than a full day? Or instead of substracting a half hour, are we adding 23.5 hours, just because of a strange combination?

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I believe that there will not be this problem because the timezone transitions of the past are more related to the daylight saving time of countries that by law no longer have daylight saving time.

baseDt = baseDt.add(difference);
}
return baseDt.add(Duration(days: value));
case TypeOid.timestampWithoutTimezone:
final value = buffer.getInt64(0);
//infinity || -infinity
Expand All @@ -807,7 +815,15 @@ class PostgresBinaryDecoder {
if (dinput.timeZone.forceDecodeTimestampAsUTC) {
return DateTime.utc(2000).add(Duration(microseconds: value));
}
return DateTime(2000).add(Duration(microseconds: value));
// https://github.com/dart-lang/sdk/issues/56312
// ignore previous timestamp transitions and use only the current system timestamp in local date and time so that the behavior is correct on Windows and Linux
final nowDt = DateTime.now();
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Let's extract these two into a method that does the correction.

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yes definitely

var baseDt = DateTime(2000);
if (baseDt.timeZoneOffset != nowDt.timeZoneOffset) {
final difference = baseDt.timeZoneOffset - nowDt.timeZoneOffset;
baseDt = baseDt.add(difference);
}
return baseDt.add(Duration(microseconds: value));

case TypeOid.timestampWithTimezone:
final value = buffer.getInt64(0);
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