Update states in DMs

Author: Thomas Stromberg

cmd/server/main.go

@@ -159,12 +159,14 @@ func run(ctx context.Context, cancel context.CancelFunc, cfg *config.ServerConfi
 	// Tokens are fetched from GSM based on team_id from org configs.
 	slackManager := slack.NewManager(cfg.SlackSigningSecret)
 
-	// Initialize state store (Datastore + JSON fallback).
+	// Initialize state store (in-memory + Datastore or JSON for persistence).
 	var stateStore interface {
 		Thread(owner, repo string, number int, channelID string) (state.ThreadInfo, bool)
 		SaveThread(owner, repo string, number int, channelID string, info state.ThreadInfo) error
 		LastDM(userID, prURL string) (time.Time, bool)
 		RecordDM(userID, prURL string, sentAt time.Time) error
+		DMMessage(userID, prURL string) (state.DMInfo, bool)
+		SaveDMMessage(userID, prURL string, info state.DMInfo) error
 		LastDigest(userID, date string) (time.Time, bool)
 		RecordDigest(userID, date string, sentAt time.Time) error
 		WasProcessed(eventKey string) bool
@@ -196,35 +198,39 @@ func run(ctx context.Context, cancel context.CancelFunc, cfg *config.ServerConfi
 	}
 
 	if datastoreDB != "" && projectID != "" {
-		slog.Info("initializing Cloud Datastore for persistent state",
+		slog.Info("initializing Cloud Datastore for persistent state (with in-memory cache)",
 			"project_id", projectID,
-			"database", datastoreDB)
+			"database", datastoreDB,
+			"cache", "in-memory")
 		var err error
 		stateStore, err = state.NewDatastoreStore(ctx, projectID, datastoreDB)
 		if err != nil {
 			// FATAL: If DATASTORE is explicitly configured, fail startup on initialization errors.
-			// This prevents silent fallback to JSON-only mode which causes duplicate messages
+			// This prevents silent fallback to memory-only mode which causes duplicate messages
 			// during rolling deployments (no cross-instance event deduplication).
 			slog.Error("FATAL: failed to initialize Cloud Datastore - DATASTORE variable is set but initialization failed",
 				"project_id", projectID,
 				"database", datastoreDB,
-				"error", err)
+				"error", err,
+				"note", "Set DATASTORE='' to use JSON files instead")
 			cancel()
 			return 1
 		}
-		slog.Info("successfully initialized Cloud Datastore",
+		slog.Info("successfully initialized Cloud Datastore with in-memory cache",
 			"project_id", projectID,
-			"database", datastoreDB)
+			"database", datastoreDB,
+			"mode", "hybrid: in-memory + Datastore")
 	} else {
 		var reason string
 		if datastoreDB == "" {
 			reason = "DATASTORE not set"
 		} else {
 			reason = "GCP_PROJECT not set and could not auto-detect"
 		}
-		slog.Info("using JSON files for state storage",
+		slog.Info("using JSON files for persistent state (with in-memory cache)",
 			"path", "os.UserCacheDir()/slacker/state",
-			"reason", reason)
+			"reason", reason,
+			"mode", "hybrid: in-memory + JSON files")
 		var err error
 		stateStore, err = state.NewJSONStore()
 		if err != nil {
@@ -241,6 +247,10 @@ func run(ctx context.Context, cancel context.CancelFunc, cfg *config.ServerConfi
 		}
 	}()
 
+	// Set state store on Slack manager for DM message tracking
+	slackManager.SetStateStore(stateStore)
+	slog.Info("configured Slack manager with state store for DM tracking")
+
 	// Initialize notification manager for multi-workspace notifications.
 	notifier := notify.New(slackManager, configManager)
 
@@ -672,6 +682,8 @@ func runBotCoordinators(
 		SaveThread(owner, repo string, number int, channelID string, info state.ThreadInfo) error
 		LastDM(userID, prURL string) (time.Time, bool)
 		RecordDM(userID, prURL string, sentAt time.Time) error
+		DMMessage(userID, prURL string) (state.DMInfo, bool)
+		SaveDMMessage(userID, prURL string, info state.DMInfo) error
 		LastDigest(userID, date string) (time.Time, bool)
 		RecordDigest(userID, date string, sentAt time.Time) error
 		WasProcessed(eventKey string) bool

internal/bot/bot.go

@@ -793,6 +793,86 @@ func (*Coordinator) extractBlockedUsersFromTurnclient(checkResult *turn.CheckRes
 	return blockedUsers
 }
 
+// updateDMMessagesForPR updates DM messages for all blocked users on a PR.
+func (c *Coordinator) updateDMMessagesForPR(ctx context.Context, checkResult *turn.CheckResponse, owner, repo string, prNumber int, title, author, prState, prURL string) {
+	if checkResult == nil || len(checkResult.Analysis.NextAction) == 0 {
+		slog.Debug("no blocked users, skipping DM updates",
+			"pr", fmt.Sprintf("%s/%s#%d", owner, repo, prNumber))
+		return
+	}
+
+	// Format the DM message (same format as initial send)
+	prefix := notify.PrefixForState(prState)
+	var action string
+	switch prState {
+	case "tests_broken":
+		action = "fix tests"
+	case "awaiting_review":
+		action = "review"
+	case "changes_requested":
+		action = "address feedback"
+	case "approved":
+		action = "merge"
+	default:
+		action = "attention needed"
+	}
+
+	message := fmt.Sprintf(
+		"%s %s <%s|%s#%d> · %s → %s",
+		prefix,
+		title,
+		prURL,
+		repo,
+		prNumber,
+		author,
+		action,
+	)
+
+	// Update DM for each blocked user
+	updatedCount := 0
+	skippedCount := 0
+	domain := c.configManager.Domain(owner)
+
+	for githubUser := range checkResult.Analysis.NextAction {
+		// Skip _system user
+		if githubUser == "_system" {
+			continue
+		}
+
+		// Map GitHub user to Slack user
+		slackUserID, err := c.userMapper.SlackHandle(ctx, githubUser, owner, domain)
+		if err != nil || slackUserID == "" {
+			slog.Debug("no Slack mapping for GitHub user, skipping DM update",
+				"github_user", githubUser,
+				"pr", fmt.Sprintf("%s/%s#%d", owner, repo, prNumber),
+				"error", err)
+			skippedCount++
+			continue
+		}
+
+		// Update the DM message
+		if err := c.slack.UpdateDMMessage(ctx, slackUserID, prURL, message); err != nil {
+			slog.Debug("failed to update DM message",
+				"user", slackUserID,
+				"github_user", githubUser,
+				"pr", fmt.Sprintf("%s/%s#%d", owner, repo, prNumber),
+				"error", err,
+				"reason", "DM may not exist or too old")
+			skippedCount++
+		} else {
+			updatedCount++
+		}
+	}
+
+	if updatedCount > 0 {
+		slog.Info("updated DM messages for PR state change",
+			"pr", fmt.Sprintf("%s/%s#%d", owner, repo, prNumber),
+			"pr_state", prState,
+			"updated", updatedCount,
+			"skipped", skippedCount)
+	}
+}
+
 // formatNextActions formats NextAction map into a compact string like "fix tests: user1, user2; review: user3".
 // It groups users by action kind and formats each action as "action_name: user1, user2".
 // Multiple actions are separated by semicolons.
@@ -888,10 +968,23 @@ func (c *Coordinator) processChannelsInParallel(
 	var validChannels []string
 	for _, channelName := range channels {
 		channelID := c.slack.ResolveChannelID(ctx, channelName)
+
+		// Check if channel resolution failed (returns original name if not found)
+		if channelID == channelName || (channelName != "" && channelName[0] == '#' && channelID == channelName[1:]) {
+			slog.Warn("could not resolve channel - may not exist or bot lacks permissions",
+				"workspace", c.workspaceName,
+				logFieldPR, fmt.Sprintf(prFormatString, prCtx.Owner, prCtx.Repo, prCtx.Number),
+				"channel", channelName,
+				"action_required", "verify channel exists and bot has access")
+			continue
+		}
+
 		if c.slack.IsBotInChannel(ctx, channelID) {
 			validChannels = append(validChannels, channelName)
 		} else {
 			slog.Warn("skipping channel - bot not a member",
+				"workspace", c.workspaceName,
+				logFieldPR, fmt.Sprintf(prFormatString, prCtx.Owner, prCtx.Repo, prCtx.Number),
 				"channel", channelName,
 				"channel_id", channelID,
 				"action_required", "invite bot to channel")
@@ -960,6 +1053,16 @@ func (c *Coordinator) processPRForChannel(
 	// Resolve channel name to ID for API calls
 	channelID := c.slack.ResolveChannelID(ctx, channelName)
 
+	// Check if channel resolution failed
+	if channelID == channelName || (channelName != "" && channelName[0] == '#' && channelID == channelName[1:]) {
+		slog.Warn("could not resolve channel for PR processing",
+			"workspace", c.workspaceName,
+			logFieldPR, fmt.Sprintf(prFormatString, owner, repo, prNumber),
+			"channel", channelName,
+			"action_required", "verify channel exists and bot has access")
+		return
+	}
+
 	// For display purposes, show both name and ID
 	var channelDisplay string
 	switch {
@@ -1025,30 +1128,28 @@ func (c *Coordinator) processPRForChannel(
 	blockedUsers := c.extractBlockedUsersFromTurnclient(checkResult)
 	domain := c.configManager.Domain(owner)
 	if len(blockedUsers) > 0 {
-		// Run email lookups in background to avoid blocking message delivery
-		// SECURITY NOTE: Use detached context to complete email lookups even during shutdown.
-		// Operations bounded by 15-second timeout. This ensures reasonably fast shutdown while
-		// completing active lookups for accurate DM delivery (most lookups hit cache instantly,
-		// but occasional cold lookups can take 10+ seconds).
-		lookupCtx, lookupCancel := context.WithTimeout(context.WithoutCancel(ctx), 15*time.Second)
-		go func() {
-			defer lookupCancel()
-			for _, githubUser := range blockedUsers {
-				// Map GitHub username to Slack user ID
-				slackUserID, err := c.userMapper.SlackHandle(lookupCtx, githubUser, owner, domain)
-				if err == nil && slackUserID != "" {
-					// Track with channelID - this will only update on FIRST call per user/PR
-					c.notifier.Tracker.UpdateUserPRChannelTag(workspaceID, slackUserID, channelID, owner, repo, prNumber)
-					slog.Debug("tracked user tag in channel (async)",
-						"workspace", workspaceID,
-						"github_user", githubUser,
-						"slack_user", slackUserID,
-						"channel", channelDisplay,
-						"channel_id", channelID,
-						"pr", fmt.Sprintf(prFormatString, owner, repo, prNumber))
-				}
+		// Record tags for blocked users synchronously to prevent race with DM sending
+		// This must complete BEFORE DM notifications check tag info
+		// Note: Most lookups hit cache and are instant; occasional cold lookups may delay slightly
+		// but this is necessary for correct DM delay logic
+		lookupCtx, lookupCancel := context.WithTimeout(ctx, 5*time.Second)
+		defer lookupCancel()
+
+		for _, githubUser := range blockedUsers {
+			// Map GitHub username to Slack user ID
+			slackUserID, err := c.userMapper.SlackHandle(lookupCtx, githubUser, owner, domain)
+			if err == nil && slackUserID != "" {
+				// Track with channelID - this will only update on FIRST call per user/PR
+				c.notifier.Tracker.UpdateUserPRChannelTag(workspaceID, slackUserID, channelID, owner, repo, prNumber)
+				slog.Debug("tracked user tag in channel",
+					"workspace", workspaceID,
+					"github_user", githubUser,
+					"slack_user", slackUserID,
+					"channel", channelDisplay,
+					"channel_id", channelID,
+					"pr", fmt.Sprintf(prFormatString, owner, repo, prNumber))
 			}
-		}()
+		}
 	}
 
 	// Build what the message SHOULD be based on current PR state
@@ -1109,6 +1210,9 @@ func (c *Coordinator) processPRForChannel(
 					"channel_id", channelID,
 					"thread_ts", threadTS,
 					"pr_state", prState)
+
+				// Also update DM messages for blocked users
+				c.updateDMMessagesForPR(ctx, checkResult, owner, repo, prNumber, event.PullRequest.Title, event.PullRequest.User.Login, prState, event.PullRequest.HTMLURL)
 			}
 		} else {
 			slog.Debug("message already matches expected content, no update needed",
@@ -1291,10 +1395,21 @@ func (c *Coordinator) createPRThread(ctx context.Context, channel, owner, repo s
 
 	// Resolve channel name to ID for consistent API calls
 	resolvedChannel := c.slack.ResolveChannelID(ctx, channel)
-	if resolvedChannel != channel {
-		slog.Debug("resolved channel for thread creation", "original", channel, "resolved", resolvedChannel)
+
+	// Check if channel resolution failed (returns original name if not found)
+	if resolvedChannel == channel || (channel != "" && channel[0] == '#' && resolvedChannel == channel[1:]) {
+		// Only warn if it's not already a channel ID
+		if channel == "" || channel[0] != 'C' {
+			slog.Warn("could not resolve channel for thread creation",
+				"workspace", c.workspaceName,
+				logFieldPR, fmt.Sprintf(prFormatString, owner, repo, number),
+				"channel", channel,
+				"action_required", "verify channel exists and bot has access")
+			return "", "", fmt.Errorf("could not resolve channel: %s", channel)
+		}
+		slog.Debug("channel is already a channel ID", "channel_id", channel)
 	} else {
-		slog.Debug("channel resolution did not change value", "channel", channel, "might_be_channel_id_already", resolvedChannel[0] == 'C')
+		slog.Debug("resolved channel for thread creation", "original", channel, "resolved", resolvedChannel)
 	}
 
 	// Create thread with resolved channel ID - post immediately without waiting for user lookups

internal/bot/polling.go

@@ -267,10 +267,17 @@ func (c *Coordinator) updateClosedPRThread(ctx context.Context, pr *github.PRSna
 	n := 0
 	for _, ch := range channels {
 		id := c.slack.ResolveChannelID(ctx, ch)
-		if id == "" {
-			slog.Debug("could not resolve channel ID for closed PR thread update",
-				"channel_name", ch,
-				"pr", prKey)
+
+		// Check if channel resolution failed (returns original name if not found)
+		if id == ch || (ch != "" && ch[0] == '#' && id == ch[1:]) {
+			slog.Warn("could not resolve channel for closed PR thread update",
+				"workspace", c.workspaceName,
+				"pr", prKey,
+				"owner", pr.Owner,
+				"repo", pr.Repo,
+				"number", pr.Number,
+				"channel", ch,
+				"action_required", "verify channel exists and bot has access")
 			continue
 		}
 

internal/notify/notify.go

@@ -297,7 +297,8 @@ func (m *Manager) NotifyUser(ctx context.Context, workspaceID, userID, channelID
 	}
 
 	// Send DM to user.
-	if err := slackClient.SendDirectMessage(ctx, userID, message); err != nil {
+	dmChannelID, messageTS, err := slackClient.SendDirectMessage(ctx, userID, message)
+	if err != nil {
 		slog.Error("failed to send DM notification",
 			"user", userID,
 			"pr", fmt.Sprintf("%s/%s#%d", pr.Owner, pr.Repo, pr.Number),
@@ -309,12 +310,23 @@ func (m *Manager) NotifyUser(ctx context.Context, workspaceID, userID, channelID
 	// Update last DM notification time.
 	m.Tracker.UpdateDMNotification(workspaceID, userID)
 
+	// Save DM message info for future updates
+	if err := slackClient.SaveDMMessageInfo(ctx, userID, pr.HTMLURL, dmChannelID, messageTS, message); err != nil {
+		slog.Warn("failed to save DM message info",
+			"user", userID,
+			"pr", fmt.Sprintf("%s/%s#%d", pr.Owner, pr.Repo, pr.Number),
+			"error", err,
+			"impact", "DM won't be updated on state changes")
+	}
+
 	slog.Info("successfully sent DM notification",
 		"user", userID,
 		"pr", fmt.Sprintf("%s/%s#%d", pr.Owner, pr.Repo, pr.Number),
 		"pr_author", pr.Author,
 		"pr_state", pr.State,
 		"action_required", action,
-		"notification_updated", true)
+		"notification_updated", true,
+		"dm_channel_id", dmChannelID,
+		"message_ts", messageTS)
 	return nil
 }