Apply channel_name_template to 1-to-1 DM rooms; track displayname template hash to force re-sync on change

pkg/connector/chatinfo.go

@@ -146,6 +146,8 @@ func (s *SlackClient) generateGroupDMName(ctx context.Context, members []string)
 			return "", err
 		}
 		ghost.UpdateInfoIfNecessary(ctx, s.UserLogin, bridgev2.RemoteEventUnknown)
+		// Use the ghost's name (output of displayname_template) so group DM names
+		// are consistent with individual DM names and puppet display names.
 		if ghost.Name != "" {
 			ghostNames = append(ghostNames, ghost.Name)
 		}
@@ -173,6 +175,18 @@ func (s *SlackClient) generateMemberList(ctx context.Context, info *slack.Channe
 	return
 }
 
+func (s *SlackClient) makeChannelNameHashExtraUpdates() func(ctx context.Context, portal *bridgev2.Portal) bool {
+	currentChannelHash := s.Main.Config.GetChannelNameTemplateHash()
+	return func(ctx context.Context, portal *bridgev2.Portal) bool {
+		meta := portal.Metadata.(*slackid.PortalMetadata)
+		if meta.ChannelNameTemplateHash != currentChannelHash {
+			meta.ChannelNameTemplateHash = currentChannelHash
+			return true
+		}
+		return false
+	}
+}
+
 func (s *SlackClient) wrapChatInfo(ctx context.Context, info *slack.Channel, isNew bool) (*bridgev2.ChatInfo, error) {
 	var members bridgev2.ChatMemberList
 	var avatar *bridgev2.Avatar
@@ -193,6 +207,7 @@ func (s *SlackClient) wrapChatInfo(ctx context.Context, info *slack.Channel, isN
 		if err != nil {
 			return nil, err
 		}
+		extraUpdates = s.makeChannelNameHashExtraUpdates()
 	case info.IsIM:
 		roomType = database.RoomTypeDM
 		members.IsFull = true
@@ -208,7 +223,11 @@ func (s *SlackClient) wrapChatInfo(ctx context.Context, info *slack.Channel, isN
 			return nil, err
 		}
 		ghost.UpdateInfoIfNecessary(ctx, s.UserLogin, bridgev2.RemoteEventUnknown)
+		// Use the ghost's name (i.e. the output of displayname_template) as the
+		// channel name input so that channel_name_template receives the same
+		// formatted name that is displayed on the puppet.
 		info.Name = ghost.Name
+		extraUpdates = s.makeChannelNameHashExtraUpdates()
 	case info.Name != "":
 		members = s.generateMemberList(ctx, info, !s.Main.Config.ParticipantSyncOnlyOnCreate || isNew)
 		if isNew && s.Main.Config.MuteChannelsByDefault {
@@ -228,10 +247,7 @@ func (s *SlackClient) wrapChatInfo(ctx context.Context, info *slack.Channel, isN
 		}
 	}
 	members.TotalMemberCount = info.NumMembers
-	var name *string
-	if roomType != database.RoomTypeDM || len(members.MemberMap) == 1 {
-		name = ptr.Ptr(s.formatChannelName(info))
-	}
+	name := ptr.Ptr(s.formatChannelName(info))
 	return &bridgev2.ChatInfo{
 		Name:         name,
 		Topic:        ptr.Ptr(info.Topic.Value),
@@ -307,9 +323,19 @@ func (s *SlackClient) GetChatInfo(ctx context.Context, portal *bridgev2.Portal)
 		return nil, fmt.Errorf("invalid portal ID %q", portal.ID)
 	} else if channelID == "" {
 		return s.getTeamInfo(), nil
-	} else {
-		return s.fetchChatInfo(ctx, channelID, portal.MXID == "")
 	}
+	// For DM and group DM portals, invalidate the chat info cache when the
+	// combined channel name template hash has changed so the portal name gets
+	// recomputed with the updated templates.
+	if portal.RoomType == database.RoomTypeDM || portal.RoomType == database.RoomTypeGroupDM {
+		meta := portal.Metadata.(*slackid.PortalMetadata)
+		if meta.ChannelNameTemplateHash != s.Main.Config.GetChannelNameTemplateHash() {
+			s.chatInfoCacheLock.Lock()
+			delete(s.chatInfoCache, channelID)
+			s.chatInfoCacheLock.Unlock()
+		}
+	}
+	return s.fetchChatInfo(ctx, channelID, portal.MXID == "")
 }
 
 func makeAvatar(avatarURL, slackAvatarHash string) *bridgev2.Avatar {
@@ -373,6 +399,7 @@ func (s *SlackClient) wrapUserInfo(userID string, info *slack.User, botInfo *sla
 		ExtraUpdates: func(ctx context.Context, ghost *bridgev2.Ghost) bool {
 			meta := ghost.Metadata.(*slackid.GhostMetadata)
 			meta.LastSync = jsontime.UnixNow()
+			meta.NameTemplateHash = s.Main.Config.GetDisplaynameTemplateHash()
 			if info != nil {
 				meta.SlackUpdatedTS = int64(info.Updated)
 			} else if botInfo != nil {
@@ -392,10 +419,15 @@ func (s *SlackClient) syncManyUsers(ctx context.Context, ghosts map[string]*brid
 		IncludeProfileOnlyUsers: true,
 		UpdatedIDs:              make(map[string]int64, len(ghosts)),
 	}
+	currentTemplateHash := s.Main.Config.GetDisplaynameTemplateHash()
 	for _, ghost := range ghosts {
 		meta := ghost.Metadata.(*slackid.GhostMetadata)
 		_, userID := slackid.ParseUserID(ghost.ID)
-		params.UpdatedIDs[userID] = meta.SlackUpdatedTS
+		lastUpdated := meta.SlackUpdatedTS
+		if meta.NameTemplateHash != currentTemplateHash {
+			lastUpdated = 0
+		}
+		params.UpdatedIDs[userID] = lastUpdated
 	}
 	zerolog.Ctx(ctx).Debug().Any("request_map", params.UpdatedIDs).Msg("Requesting user info")
 	infos, err := s.Client.GetUsersCacheContext(ctx, s.TeamID, params)
@@ -465,7 +497,8 @@ func (s *SlackClient) GetUserInfo(ctx context.Context, ghost *bridgev2.Ghost) (*
 		return nil, nil
 	}
 	meta := ghost.Metadata.(*slackid.GhostMetadata)
-	if time.Since(meta.LastSync.Time) < MinGhostSyncInterval {
+	templateChanged := meta.NameTemplateHash != s.Main.Config.GetDisplaynameTemplateHash()
+	if !templateChanged && time.Since(meta.LastSync.Time) < MinGhostSyncInterval {
 		return nil, nil
 	}
 	if s.IsRealUser && (ghost.Name != "" || time.Since(s.initialConnect) < 1*time.Minute) {

pkg/connector/config.go

@@ -18,6 +18,8 @@ package connector
 
 import (
 	_ "embed"
+	"crypto/sha256"
+	"fmt"
 	"strings"
 	"text/template"
 
@@ -42,9 +44,11 @@ type Config struct {
 
 	Backfill BackfillConfig `yaml:"backfill"`
 
-	displaynameTemplate *template.Template `yaml:"-"`
-	channelNameTemplate *template.Template `yaml:"-"`
-	teamNameTemplate    *template.Template `yaml:"-"`
+	displaynameTemplate     *template.Template `yaml:"-"`
+	channelNameTemplate     *template.Template `yaml:"-"`
+	teamNameTemplate        *template.Template `yaml:"-"`
+	displaynameTemplateHash  string             `yaml:"-"`
+	channelNameTemplateHash  string             `yaml:"-"`
 }
 
 type BackfillConfig struct {
@@ -64,10 +68,16 @@ func (c *Config) UnmarshalYAML(node *yaml.Node) error {
 	if err != nil {
 		return err
 	}
+	h := sha256.Sum256([]byte(c.DisplaynameTemplate))
+	c.displaynameTemplateHash = fmt.Sprintf("%x", h[:8])
 	c.channelNameTemplate, err = template.New("channel_name").Parse(c.ChannelNameTemplate)
 	if err != nil {
 		return err
 	}
+	// The channel name for DMs depends on both displayname_template (which determines ghost.Name,
+	// used as .Name input) and channel_name_template (the outer format). Hash both together.
+	ch := sha256.Sum256([]byte(c.ChannelNameTemplate + "\x00" + c.DisplaynameTemplate))
+	c.channelNameTemplateHash = fmt.Sprintf("%x", ch[:8])
 	c.teamNameTemplate, err = template.New("team_name").Parse(c.TeamNameTemplate)
 	if err != nil {
 		return err
@@ -90,6 +100,14 @@ func (c *Config) FormatDisplayname(user *DisplaynameParams) string {
 	return executeTemplate(c.displaynameTemplate, user)
 }
 
+func (c *Config) GetDisplaynameTemplateHash() string {
+	return c.displaynameTemplateHash
+}
+
+func (c *Config) GetChannelNameTemplateHash() string {
+	return c.channelNameTemplateHash
+}
+
 func (c *Config) FormatBotDisplayname(bot *slack.Bot, team *slack.TeamInfo) string {
 	return c.FormatDisplayname(&DisplaynameParams{
 		User: &slack.User{

pkg/connector/example-config.yaml

@@ -19,7 +19,9 @@
 #  .Profile.Phone - The formatted phone number of the user
 displayname_template: '{{or .Profile.DisplayName .Profile.RealName .Name}}{{if .IsBot}} (bot){{end}}'
 # Channel name template for Slack channels (all types). Available variables:
-#  .Name - The name of the channel
+#  .Name - The name of the channel; for DMs (.IsIM) the other user's name as formatted by
+#          displayname_template; for group DMs (.IsMpIM) a comma-separated list of members'
+#          names, each also formatted by displayname_template
 #  .Team.Name - The name of the team the channel is in
 #  .Team.Domain - The Slack subdomain of the team the channel is in
 #  .ID - The internal ID of the channel

pkg/slackid/dbmeta.go

@@ -25,11 +25,15 @@ type PortalMetadata struct {
 	TeamDomain  string `json:"team_domain,omitempty"`
 	EditMaxAge  *int   `json:"edit_max_age,omitempty"`
 	AllowDelete *bool  `json:"allow_delete,omitempty"`
+	// Hash of channel_name_template + displayname_template; used to detect when
+	// DM/group DM portal names need to be refreshed after a config change.
+	ChannelNameTemplateHash string `json:"channel_name_template_hash,omitempty"`
 }
 
 type GhostMetadata struct {
-	SlackUpdatedTS int64         `json:"slack_updated_ts"`
-	LastSync       jsontime.Unix `json:"last_sync"`
+	SlackUpdatedTS   int64         `json:"slack_updated_ts"`
+	LastSync         jsontime.Unix `json:"last_sync"`
+	NameTemplateHash string        `json:"name_template_hash,omitempty"`
 }
 
 type UserLoginMetadata struct {