MM-24674 Update channel members by group to look at distinct timezones correctly (#14673)

* MM-24674 Update channel members by group to look at distinct autoTimezone and manualTimezone.

Instead of just doing a blanket distinct on the column since that returns more entries than expected

* Use JSON extract instead of parsing text

* Use single quotes in mysql query too

* Dont need to prepend users on unambiguous column

* Use json extract instead of shorthand

* Dont count timezone if timezone default length

* CI

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

store/sqlstore/channel_store.go

@@ -1811,7 +1811,27 @@ func (s SqlChannelStore) GetMemberCountsByGroup(channelID string, includeTimezon
 	selectStr := "GroupMembers.GroupId, COUNT(ChannelMembers.UserId) AS ChannelMemberCount"
 
 	if includeTimezones {
-		selectStr = "GroupMembers.GroupId, COUNT(ChannelMembers.UserId) AS ChannelMemberCount, COUNT( DISTINCT Users.Timezone ) AS ChannelMemberTimezonesCount"
+		distinctTimezones := `
+			DISTINCT(
+				CASE WHEN JSON_EXTRACT(Timezone, '$.useAutomaticTimezone') = 'true' AND LENGTH(Timezone) > 74
+				THEN JSON_EXTRACT(Timezone, '$.automaticTimezone')
+				WHEN LENGTH(Timezone) > 74
+				THEN JSON_EXTRACT(Timezone, '$.manualTimezone')
+				END
+			)
+		`
+		if s.DriverName() == model.DATABASE_DRIVER_POSTGRES {
+			distinctTimezones = `
+				DISTINCT(
+					CASE WHEN Timezone::json->>'useAutomaticTimezone' = 'true' AND LENGTH(Timezone) > 74
+					THEN Timezone::json->>'automaticTimezone'
+					WHEN LENGTH(Timezone) > 74
+					THEN Timezone::json->>'manualTimezone'
+					END
+				)
+			`
+		}
+		selectStr = `GroupMembers.GroupId, COUNT(ChannelMembers.UserId) AS ChannelMemberCount, COUNT(` + distinctTimezones + `) AS ChannelMemberTimezonesCount`
 	}
 
 	query := s.getQueryBuilder().

store/storetest/channel_store.go

@@ -18,6 +18,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/services/timezones"
 	"github.com/mattermost/mattermost-server/v5/store"
+	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
 type SqlSupplier interface {
@@ -4335,13 +4336,13 @@ func testGetMemberCountsByGroup(t *testing.T, ss store.Store) {
 		require.Equal(t, expectedMemberCounts, memberCounts)
 	})
 
-	t.Run("returns memberCountsByGroup with timezones", func(t *testing.T) {
+	t.Run("returns memberCountsByGroup with timezones when no timezones set", func(t *testing.T) {
 		memberCounts, err = ss.Channel().GetMemberCountsByGroup(c1.Id, true)
 		expectedMemberCounts := []*model.ChannelMemberCountByGroup{
 			{
 				GroupId:                     g1.Id,
 				ChannelMemberCount:          1,
-				ChannelMemberTimezonesCount: 1,
+				ChannelMemberTimezonesCount: 0,
 			},
 		}
 		require.Nil(t, err)
@@ -4362,6 +4363,7 @@ func testGetMemberCountsByGroup(t *testing.T, ss store.Store) {
 		timeZone := timezones.DefaultUserTimezone()
 		if i == 1 {
 			timeZone["manualTimezone"] = "EDT"
+			timeZone["useAutomaticTimezone"] = "false"
 		}
 
 		u := &model.User{
@@ -4399,10 +4401,20 @@ func testGetMemberCountsByGroup(t *testing.T, ss store.Store) {
 	// create 10 different users with 3 different timezones for group 3
 	for i := 1; i <= 10; i++ {
 		timeZone := timezones.DefaultUserTimezone()
-		if i == 1 {
+
+		if i == 1 || i == 2 {
 			timeZone["manualTimezone"] = "EDT"
-		} else if i == 2 {
+			timeZone["useAutomaticTimezone"] = "false"
+		} else if i == 3 || i == 4 {
 			timeZone["manualTimezone"] = "PST"
+			timeZone["useAutomaticTimezone"] = "false"
+		} else if i == 5 || i == 6 {
+			timeZone["autoTimezone"] = "PST"
+			timeZone["useAutomaticTimezone"] = "true"
+		} else {
+			// Give every user with auto timezone set to true a random manual timezone to ensure that manual timezone is not looked at if auto is set
+			timeZone["useAutomaticTimezone"] = "true"
+			timeZone["manualTimezone"] = "PST" + utils.RandomName(utils.Range{Begin: 5, End: 5}, utils.ALPHANUMERIC)
 		}
 
 		u := &model.User{
@@ -4456,12 +4468,12 @@ func testGetMemberCountsByGroup(t *testing.T, ss store.Store) {
 			{
 				GroupId:                     g1.Id,
 				ChannelMemberCount:          1,
-				ChannelMemberTimezonesCount: 1,
+				ChannelMemberTimezonesCount: 0,
 			},
 			{
 				GroupId:                     g2.Id,
 				ChannelMemberCount:          5,
-				ChannelMemberTimezonesCount: 2,
+				ChannelMemberTimezonesCount: 1,
 			},
 			{
 				GroupId:                     g3.Id,