data: Don't add a timezone when coercing to a date

If we're coercing a timestamp that has no timezone to a date, make sure
that the resulting date also doesn't have a timezone. This fixes a bug
where we wouldn't be able to do lookups into a date field using
timestamps that had the same date

Refs: ENG-2997
Change-Id: I86bc165fe40c2e19c650df707e852da4c9968526
Reviewed-on: https://gerrit.readyset.name/c/readyset/+/4868
Tested-by: Buildkite CI
Reviewed-by: Fran Noriega <fran@readyset.io>

logictests/date_params.test

@@ -0,0 +1,18 @@
+statement ok
+CREATE TABLE `table_1` (`column_2` INT, `column_1` DATE, PRIMARY KEY (`column_2`))
+
+
+statement ok
+INSERT INTO `table_1` (`column_2`, `column_1`) VALUES (0, '2020-01-01')
+
+onlyif readyset
+statement ok
+create cache from SELECT dayofweek(`table_1`.`column_1`) AS `alias_1` FROM `table_1` WHERE (`table_1`.`column_1` = ?)
+
+graphviz
+
+query  rowsort
+SELECT count(*) AS `alias_1` FROM `table_1` WHERE (`table_1`.`column_1` = ?)
+? = 2020-01-01 00:00:00
+----
+1

readyset-data/src/timestamp.rs

@@ -39,7 +39,7 @@ pub const DATE_FORMAT: &str = "%Y-%m-%d";
 ///
 /// Sadly the way chrono implements `DateTime<Tz>` occupies at least 16 bytes, and therefore
 /// overflows DfValue. So this type internally stores a [`NaiveDateTime`] with a 3 byte
-/// of extra data. Since 3 bytes allow us to store 24 bytes, this is how we use them:
+/// of extra data. Since 3 bytes allow us to store 24 bits, this is how we use them:
 ///
 /// 17 bits for the timezone offset (0 to 86_400)
 /// 1 bit to signify negative offset
@@ -350,7 +350,11 @@ impl TimestampTz {
                 ts.set_subsecond_digits(subsecond_digits as u8);
                 Ok(DfValue::TimestampTz(ts))
             }
-            DfType::Date => Ok(DfValue::TimestampTz(self.to_chrono().date().into())),
+            DfType::Date => Ok(if self.has_timezone() {
+                DfValue::TimestampTz(self.to_chrono().date().into())
+            } else {
+                DfValue::TimestampTz(self.to_chrono().date_naive().into())
+            }),
             // TODO(ENG-1833): Use `subsecond_digits` value.
             DfType::Time { .. } => Ok(self.to_chrono().naive_local().time().into()),