Issue parsing timestamp with timezone having offset of format +hh:mm:ss

[khlopkov]

Feature Request

Is your feature request related to a problem? Please describe

tested on postgres:10-alpine docker image

I have an issue when trying to parse timestamp with timezone in format of 0001-01-01 08:20:53+02:30:17 to LocalDateTime/OffsetDateTime/ZonedDateTime. Here is an example test code on groovy:

def temp() {
        Function<Row, OffsetDateTime> fn = note -> note.get("datetime", OffsetDateTime)

        expect:
        def datetime = databaseClient.sql("SELECT '0001-01-01 08:20:53+02:30:17'::timestamptz as datetime")
            .map(fn).first()
            .block()
    }

which giving following stacktrace:

Text '0001-01-01 08:20:53+02:30:17' could not be parsed, unparsed text found at index 25
java.time.format.DateTimeParseException: Text '0001-01-01 08:20:53+02:30:17' could not be parsed, unparsed text found at index 25
	at java.base/java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:2055)
	at java.base/java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1954)
	at io.r2dbc.postgresql.codec.AbstractTemporalCodec.decodeTemporal(AbstractTemporalCodec.java:135)
	at io.r2dbc.postgresql.codec.AbstractTemporalCodec.decodeTemporal(AbstractTemporalCodec.java:95)

Describe the solution you'd like

it seems that for year which is lower then 1920 postgres does not convert timestamp with timezone to format of +hh:00:00 and leaves it in unformatted way (e. g. +02:30:17).
This could be fixed by adding following change to PostgresqlDateTimeFormatter

-            .appendOffset("+HH:mm", "+00:00")
+            .appendOffset("+HH:mm:ss", "+00:00:00")

Describe alternatives you've considered

Conversion of offset could be fixed in postgresql which will take more time, I suppose

Teachability, Documentation, Adoption, Migration Strategy

Nothing to document