From 096c8e061c8e99d0dbf7a6f0a7a5399239790b3b Mon Sep 17 00:00:00 2001
From: Rohan Yadav <rohany@alumni.cmu.edu>
Date: Tue, 28 May 2019 15:28:11 -0400
Subject: [PATCH] sql: Allow 24:00 and variants to be parsed

Fixes: #36118

Release note (sql change): Add support for the time value 24:00 and variants.
---
 pkg/sql/logictest/testdata/logic_test/time | 19 ++++++++++++++++++-
 pkg/sql/sem/tree/datum.go                  | 11 +++++++++++
 pkg/sql/sem/tree/datum_test.go             |  6 +++++-
 pkg/util/timeofday/time_of_day.go          | 11 +++++++++--
 4 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/pkg/sql/logictest/testdata/logic_test/time b/pkg/sql/logictest/testdata/logic_test/time
index 4abbf001e9b3..7b2c6a9bf6dc 100644
--- a/pkg/sql/logictest/testdata/logic_test/time
+++ b/pkg/sql/logictest/testdata/logic_test/time
@@ -23,8 +23,25 @@ SELECT '23:59:59.999999':::TIME;
 ----
 0000-01-01 23:59:59.999999 +0000 UTC
 
+query T
+select ('24:00'::TIME)::STRING
+----
+24:00:00
+
+query T
+SELECT ('24:00:00'::TIME)::STRING
+----
+24:00:00
+
 statement error could not parse
-SELECT '24:00:00':::TIME;
+SELECT '124:00'::TIME;
+
+statement error could not parse
+SELECT '24:00:01'::TIME;
+
+statement error could not parse
+SELECT '24:00:00.001'::TIME;
+
 
 # Timezone should be ignored.
 query T
diff --git a/pkg/sql/sem/tree/datum.go b/pkg/sql/sem/tree/datum.go
index 4cc771e272b9..6cab07ef4780 100644
--- a/pkg/sql/sem/tree/datum.go
+++ b/pkg/sql/sem/tree/datum.go
@@ -20,6 +20,7 @@ import (
 	"math"
 	"math/big"
 	"net"
+	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -64,6 +65,9 @@ var (
 
 	// DZero is the zero-valued integer Datum.
 	DZero = NewDInt(0)
+
+	// DTimeRegex is a compiled regex for parsing the 24:00 time value
+	DTimeRegex = regexp.MustCompile("^24:00($|(:00$)|(:00.0+$))")
 )
 
 // Datum represents a SQL value.
@@ -1817,6 +1821,13 @@ func MakeDTime(t timeofday.TimeOfDay) *DTime {
 // provided string, or an error if parsing is unsuccessful.
 func ParseDTime(ctx ParseTimeContext, s string) (*DTime, error) {
 	now := relativeParseTime(ctx)
+
+	// special case on 24:00 and 24:00:00 as the parser
+	// does not handle these correctly.
+	if DTimeRegex.MatchString(s) {
+		return MakeDTime(timeofday.Time2400), nil
+	}
+
 	t, err := pgdate.ParseTime(now, 0 /* mode */, s)
 	if err != nil {
 		// Build our own error message to avoid exposing the dummy date.
diff --git a/pkg/sql/sem/tree/datum_test.go b/pkg/sql/sem/tree/datum_test.go
index 21bce9b6e34d..b914b5e1b40d 100644
--- a/pkg/sql/sem/tree/datum_test.go
+++ b/pkg/sql/sem/tree/datum_test.go
@@ -105,6 +105,8 @@ func TestDatumOrdering(t *testing.T) {
 			`'00:00:00'`, `'23:59:59.999999'`},
 		{`'23:59:59.999999':::time`, `'23:59:59.999998'`, valIsMax,
 			`'00:00:00'`, `'23:59:59.999999'`},
+		{`'24:00':::time`, `'23:59:59.999999'`, `'00:00:00.000001'`,
+			`'00:00:00'`, `'23:59:59.999999'`},
 
 		// Intervals
 		{`'1 day':::interval`, noPrev, noNext,
@@ -484,6 +486,9 @@ func TestParseDTime(t *testing.T) {
 		{"04:05:06.000001", timeofday.New(4, 5, 6, 1)},
 		{"04:05:06-07", timeofday.New(4, 5, 6, 0)},
 		{"4:5:6", timeofday.New(4, 5, 6, 0)},
+		{"24:00:00", timeofday.Time2400},
+		{"24:00:00.000", timeofday.Time2400},
+		{"24:00:00.000000", timeofday.Time2400},
 	}
 	for _, td := range testData {
 		actual, err := tree.ParseDTime(nil, td.str)
@@ -502,7 +507,6 @@ func TestParseDTimeError(t *testing.T) {
 		"",
 		"foo",
 		"01",
-		"24:00:00",
 	}
 	for _, s := range testData {
 		actual, _ := tree.ParseDTime(nil, s)
diff --git a/pkg/util/timeofday/time_of_day.go b/pkg/util/timeofday/time_of_day.go
index f53fcef429a1..1156d7df4738 100644
--- a/pkg/util/timeofday/time_of_day.go
+++ b/pkg/util/timeofday/time_of_day.go
@@ -31,9 +31,13 @@ type TimeOfDay int64
 const (
 	// Min is the minimum TimeOfDay value (midnight).
 	Min = TimeOfDay(0)
-	// Max is the maximum TimeOfDay value (1 microsecond before midnight).
+
+	// Max is the maximum TimeOfDay value (1 second before midnight)
 	Max = TimeOfDay(microsecondsPerDay - 1)
 
+	// Time2400 is a special value to represent the 24:00 input time
+	Time2400 = TimeOfDay(microsecondsPerDay)
+
 	microsecondsPerSecond = 1e6
 	microsecondsPerMinute = 60 * microsecondsPerSecond
 	microsecondsPerHour   = 60 * microsecondsPerMinute
@@ -107,8 +111,11 @@ func Difference(t1 TimeOfDay, t2 TimeOfDay) duration.Duration {
 	return duration.MakeDuration(int64(t1-t2)*nanosPerMicro, 0, 0)
 }
 
-// Hour returns the hour specified by t, in the range [0, 23].
+// Hour returns the hour specified by t, in the range [0, 24].
 func (t TimeOfDay) Hour() int {
+	if t == Time2400 {
+		return 24
+	}
 	return int(int64(t)%microsecondsPerDay) / microsecondsPerHour
 }