pgdate: Improve handling of negative years

pkg/sql/logictest/testdata/logic_test/datetime

@@ -1193,3 +1193,33 @@ query T
 SELECT date_trunc('month', "date") AS date_trunc_month_created_at FROM "topics";
 ----
 2017-12-01 00:00:00 +0000 UTC
+
+
+# Test negative years to ensure they can round-trip through the parser.
+# Also ensure that we don't trigger any of the "convenience" rules.
+subtest regression_35255
+
+query T
+SELECT '-56325279622-12-26'::DATE
+----
+-56325279622-12-26 00:00:00 +0000 +0000
+
+query T
+SELECT '-5632-12-26'::DATE
+----
+-5632-12-26 00:00:00 +0000 +0000
+
+query T
+SELECT '-563-12-26'::DATE
+----
+-0563-12-26 00:00:00 +0000 +0000
+
+query T
+SELECT '-56-12-26'::DATE
+----
+-0056-12-26 00:00:00 +0000 +0000
+
+query T
+SELECT '-5-12-26'::DATE
+----
+-0005-12-26 00:00:00 +0000 +0000

pkg/util/timeutil/pgdate/field_extract.go

@@ -320,12 +320,13 @@ func (fe *fieldExtract) interpretNumber(chunk numberChunk, textMonth bool) error
 	case fe.Wants(fieldYear) && fe.Wants(fieldMonth) && fe.Wants(fieldDay):
 		// Example: All date formats, we're starting from scratch.
 		switch {
-		case chunk.magnitude >= 6:
+		case chunk.magnitude >= 6 && chunk.separator != '-':
 			// Example: "YYMMDD"
 			//           ^^^^^^
 			// Example: "YYYYMMDD"
 			//           ^^^^^^^^
-			// We're looking at some kind of concatenated date.
+			// We're looking at some kind of concatenated date. We do want
+			// to exclude large-magnitude, negative years from this test.
 
 			// Record whether or not it's a two-digit year.
 			fe.tweakYear = chunk.magnitude == 6
@@ -350,7 +351,9 @@ func (fe *fieldExtract) interpretNumber(chunk numberChunk, textMonth bool) error
 			// year-first mode, we'll accept the first chunk and possibly
 			// adjust a two-digit value later on.  This means that
 			// 99 would get adjusted to 1999, but 0099 would not.
-			if chunk.magnitude <= 2 {
+			if chunk.separator == '-' {
+				chunk.v *= -1
+			} else if chunk.magnitude <= 2 {
 				fe.tweakYear = true
 			}
 			return fe.SetChunk(fieldYear, chunk)

pkg/util/timeutil/pgdate/parsing.go

@@ -147,7 +147,7 @@ func ParseTimestamp(now time.Time, mode ParseMode, s string) (time.Time, error)
 
 // badFieldPrefixError constructs a CodeInvalidDatetimeFormatError pgerror.
 func badFieldPrefixError(field field, prefix rune) error {
-	return inputErrorf("unexpected separator '%v' for field %s", prefix, field.Pretty())
+	return inputErrorf("unexpected separator '%s' for field %s", string(prefix), field.Pretty())
 }
 
 // inputErrorf returns a CodeInvalidDatetimeFormatError pgerror.