Respect calendar type of Ruby and PostgreSQL - #736
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August 8, 2026 20:14
PostgreSQL uses gregorian calendar for all dates. It is described here: https://www.postgresql.org/docs/10/datetime-units-history.html Ruby treats dates before 1852-10-05 as julian calendar and after 1582-10-14 as gregorian calendar. It is described here: https://docs.ruby-lang.org/en/master/language/calendars_rdoc.html#argument-start In order to encode and decode the correct date, this PR encodes Date values send to the server as gregorian calendar. Non-gregorian dates are converted to gregorian calender before sent. The other way around, Date values decoded from the server are explicit interpret and labeled as gregorian calendar. The new behavior could be surprising when a julian date is passed through the server and changed to gregorian like so. But it is how the two parties represent one and the same date: ```ruby conn.exec_params("SELECT $1::date", [Date.new(1581, 5, 15)]).values => [[#<Date: 1581-05-25 ((2298653j,0s,0n),+0s,-Infj)>]] ``` So far the PG::BasicTypeMapForQueries didn't use the Date encoder. This was because it didn't have an advantage over standard `to_s` conversion. Now that the encoder ensures that the date is sent as gregorian calender value, it makes sense to enable it for query parameters. Fixes ged#725
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PostgreSQL uses gregorian calendar for all dates.
It is described here:
https://www.postgresql.org/docs/10/datetime-units-history.html
Ruby treats dates before 1852-10-05 as julian calendar and after 1582-10-14 as gregorian calendar. It is described here:
https://docs.ruby-lang.org/en/master/language/calendars_rdoc.html#argument-start
In order to encode and decode the correct date, this PR encodes Date values send to the server as gregorian calendar. Non-gregorian dates are converted to gregorian calender before sent. The other way around, Date values decoded from the server are explicit interpret and labeled as gregorian calendar.
The new behavior could be surprising when a julian date is passed through the server and changed to gregorian like so. But it is how the two parties represent one and the same date:
So far the PG::BasicTypeMapForQueries didn't use the Date encoder. This was because it didn't have an advantage over standard
to_sconversion. Now that the encoder ensures that the date is sent as gregorian calender value, it makes sense to enable it for query parameters.Fixes #725